Health Canada has completed a safety review confirming that the use of nonsteroidal anti-inflammatory drugs (NSAIDs) starting from approximately 20 weeks of pregnancy or later may cause rare but serious kidney problems in an unborn baby. This can lead to low levels of amniotic fluid and possible complications, such as impaired lung maturation and limb contractures in the newborn baby. Health Canada is advising that pregnant women not use NSAIDs from approximately 20 to 28 weeks of pregnancy unless advised to do so by their health care provider. If a health care provider decides the use of NSAIDs between 20 and 28 weeks of pregnancy is necessary, Health Canada recommends that they use the lowest effective dose for the shortest duration possible and consider monitoring amniotic fluid levels via ultrasound if treatment extends beyond 48 hours. The use of NSAIDs remains contraindicated in the last trimester of pregnancy. The recommendations do not apply to the use of low-dose (81 mg) aspirin, pediatric-only formulations (those indicated only for children younger than 12 years), or ophthalmic formulations. Prescription and nonprescription NSAID product labels will be updated with this new information.
Further information is available at https://healthycanadians.gc.ca/recall-alert-rappel-avis/hc-sc/2021/75763a-eng.php.
Nonsteroidal anti-inflammatory drugs (NSAIDs) cause an increased risk of serious cardiovascular thrombotic events, including myocardial infarction (MI) and stroke, which can be fatal. This risk may occur early in treatment and may increase with duration of use.
Mefenamic acid is contraindicated in the setting of coronary artery bypass graft (CABG) surgery.
NSAIDs cause an increased risk of serious gastrointestinal (GI) adverse events, including bleeding, ulceration, and perforation of the stomach or intestines, which can be fatal. These events can occur at any time during use and without warning symptoms. Elderly patients and patients with a prior history of peptic ulcer disease and/or GI bleeding are at greater risk for serious GI events.
Note: Safety: Use the lowest effective dose for the shortest duration of time. Avoid or use with caution in patients at risk for or with existing cardiovascular disease, GI disease, kidney impairment, chronic liver disease, or a bleeding diathesis due to greater risk for adverse events. Consider administering in combination with a proton pump inhibitor in patients at risk for GI bleeding (eg, taking dual antiplatelet therapy or an anticoagulant, ≥60 years of age, high doses) (ACCF/ACG/AHA [Abraham 2010]; ACCF/ACG/AHA [Bhatt 2008]).
Pain, mild to moderate: Oral: Initial: 500 mg, then 250 mg every 6 hours as needed; usually not to exceed 1 week.
Primary dysmenorrhea: Oral: Initial: 500 mg beginning at the onset of bleeding and associated symptoms, followed by 250 mg every 6 hours (manufacturer's labeling) or 500 mg 3 times daily (Delgado 1994; De Mello 2004; Langrick 1989); usually not to exceed 3 days.
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Avoid use in patients with preexisting renal disease and in patients with advanced renal disease.
KDIGO 2012 guidelines provide the following recommendations for NSAIDs:
eGFR 30 to <60 mL/minute/1.73 m2: Temporarily discontinue in patients with intercurrent disease that increases risk of acute kidney injury.
eGFR <30 mL/minute/1.73 m2: Avoid use.
Hepatic impairment prior to treatment initiation: There are no dosage adjustments provided in the manufacturer's labeling (has not been studied); however, adjustment may be necessary due to extensive hepatic metabolism.
Hepatotoxicity during treatment: Discontinue if clinical signs and symptoms of liver disease develop, or if systemic manifestations occur.
Pain, mild to moderate: Adolescents ≥14 years: Refer to adult dosing.
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Avoid use in patients with preexisting renal disease and in patients with advanced renal disease.
KDIGO 2012 guidelines provide the following recommendations for NSAIDs:
eGFR 30 to <60 mL/minute/1.73 m2: Temporarily discontinue in patients with intercurrent disease that increases risk of acute kidney injury.
eGFR <30 mL/minute/1.73 m2: Avoid use.
There are no dosage adjustments provided in the manufacturer’s labeling (has not been studied); however, adjustment may be necessary due to extensive hepatic metabolism.
Refer to adult dosing. Use with caution; initiate dose at lower end of the dosing range.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Capsule, Oral:
Generic: 250 mg
Yes
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Capsule, Oral:
Ponstan: 250 mg [contains brilliant blue fcf (fd&c blue #1), fd&c yellow #10 (quinoline yellow), fd&c yellow #6 (sunset yellow)]
Generic: 250 mg
An FDA-approved patient medication guide, which is available with the product information and at https://www.fda.gov/media/73125/download, must be dispensed with this medication.
Oral: May administer with food to reduce GI upset (Hamaguchi 1986).
Oral: May take with food if it causes an upset stomach.
Pain, mild to moderate: Relief of mild to moderate pain in patients ≥14 years, when therapy will not exceed 1 week.
Primary dysmenorrhea: Treatment of primary dysmenorrhea.
Ponstel may be confused with Pronestyl
Beers Criteria: Mefenamic acid is identified in the Beers Criteria as a potentially inappropriate medication to be avoided for chronic use in patients 65 years and older (unless alternative agents ineffective and patient can receive concomitant gastroprotective agent) due to increased risk of GI bleeding and peptic ulcer disease in older adults in high risk category (eg, older than 75 years or receiving concomitant oral/parenteral corticosteroids, anticoagulants, or antiplatelet agents) (Beers Criteria [AGS 2019]).
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.
1% to 10%:
Central nervous system: Dizziness (3% to 9%), headache, nervousness
Dermatologic: Pruritus, skin rash
Endocrine & metabolic: Fluid retention
Gastrointestinal: Abdominal cramps, abdominal distress, abdominal pain, constipation, diarrhea, duodenal ulcer (with bleeding or perforation), dyspepsia, flatulence, gastric ulcer (with bleeding or perforation), gastritis, heartburn, nausea, vomiting
Hematologic & oncologic: Hemorrhage
Hepatic: Increased liver enzymes
Otic: Tinnitus
<1%, postmarketing, and/or case reports: Acute renal failure, agranulocytosis, allergic rhinitis, anemia, angioedema, aseptic meningitis, auditory impairment, blurred vision, bone marrow depression, cardiac arrhythmia, cardiac failure, confusion, conjunctivitis, cystitis, depression, drowsiness, dyspnea, epistaxis, erythema multiforme, gastrointestinal ulcer, hallucination, hemolytic anemia, hepatitis, hepatotoxicity (idiosyncratic; Chalasani 2014), hot flash, hypertension, insomnia, leukopenia, peripheral neuropathy, polydipsia, polyuria, Stevens-Johnson syndrome, stomatitis, tachycardia, thrombocytopenia, toxic amblyopia, toxic epidermal necrolysis, urticaria, xerophthalmia
Hypersensitivity to mefenamic acid, or any component of the formulation; use in the setting of coronary artery bypass graft (CABG) surgery; history of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs.
Canadian labeling: Additional contraindications (not in US labeling): Pregnancy (third trimester); breast-feeding; severe uncontrolled heart failure; active gastric, duodenal, or peptic ulcer; active gastrointestinal bleeding; cerebrovascular bleeding or other bleeding disorders; inflammatory bowel disease; severe hepatic impairment or active hepatic disease; severe renal impairment (CrCl <30 mL/minute) or deteriorating renal disease; known hyperkalemia; adolescents <18 years of age
Concerns related to adverse effects:
• Anaphylactoid reactions: Even in patients without prior exposure anaphylactoid reactions may occur; patients with "aspirin triad" (bronchial asthma, aspirin intolerance, rhinitis) may be at increased risk. Contraindicated in patients who experience bronchospasm, asthma, rhinitis, or urticaria with nonsteroidal anti-inflammatory drug (NSAID) or aspirin therapy.
• Cardiovascular events: [US Boxed Warning]: NSAIDs cause an increased risk of serious (and potentially fatal) adverse cardiovascular thrombotic events, including MI and stroke. Risk may occur early during treatment and may increase with duration of use. Relative risk appears to be similar in those with and without known cardiovascular disease or risk factors for cardiovascular disease; however, absolute incidence of serious cardiovascular thrombotic events (which may occur early during treatment) was higher in patients with known cardiovascular disease or risk factors and in those receiving higher doses. New onset hypertension or exacerbation of hypertension may occur (NSAIDs may also impair response to ACE inhibitors, thiazide diuretics, or loop diuretics); may contribute to cardiovascular events; monitor blood pressure; use with caution in patients with hypertension. May cause sodium and fluid retention; use with caution in patients with edema. Avoid use in heart failure (ACCF/AHA [Yancy 2013]). Avoid use in patients with recent MI unless benefits outweigh risk of cardiovascular thrombotic events. Use the lowest effective dose for the shortest duration of time, consistent with individual patient goals, to reduce risk of cardiovascular events; alternate therapies should be considered for patients at high risk.
• CNS effects: May cause drowsiness, dizziness, blurred vision, and other neurologic effects which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).
• Drug reaction with eosinophilia and systemic symptoms: Potentially serious, sometimes fatal, drug reaction with eosinophilia and systemic symptoms (DRESS), also known as multiorgan hypersensitivity reactions, has been reported with NSAIDs. Monitor for signs and symptoms (eg, fever, rash, lymphadenopathy, eosinophilia) in association with other organ system involvement (eg, hepatitis, nephritis, hematological abnormalities, myocarditis, myositis). Early symptoms of hypersensitivity reaction (eg, lymphadenopathy, fever) may occur without rash; discontinue therapy and further evaluate if DRESS is suspected.
• GI events: [US Boxed Warning]: NSAIDs cause increased risk of serious GI inflammation, ulceration, bleeding, and perforation (may be fatal); elderly patients and patients with history of peptic ulcer disease and/or GI bleeding are at greater risk for serious GI events. These events may occur at any time during therapy and without warning. Avoid use in patients with active GI bleeding. In patients with a history of acute lower GI bleeding, avoid use of non-aspirin NSAIDs, especially if due to angioectasia or diverticulosis (Strate 2016). Use caution with a history of GI ulcers, concurrent therapy known to increase the risk of GI bleeding (eg, aspirin, anticoagulants and/or corticosteroids, selective serotonin reuptake inhibitors), advanced hepatic disease, coagulopathy, smoking, use of alcohol, or in the elderly or debilitated patients. Use the lowest effective dose for the shortest duration of time, consistent with individual patient goals, to reduce risk of GI adverse events; alternate therapies should be considered for patients at high risk. When used concomitantly with aspirin, a substantial increase in the risk of GI complications (eg, ulcer) occurs; concomitant gastroprotective therapy (eg, proton pump inhibitors) is recommended (ACCF/ACG/AHA [Bhatt 2008]).
• Hematologic effects: Platelet adhesion and aggregation may be decreased; may prolong bleeding time; patients with coagulation disorders or who are receiving anticoagulants should be monitored closely. Anemia may occur; patients on long-term NSAID therapy should be monitored for anemia. Rarely, NSAID use has been associated with potentially severe blood dyscrasias (eg, agranulocytosis, thrombocytopenia, aplastic anemia).
• Hepatic effects: Transaminase elevations have been reported with use; closely monitor patients with any abnormal LFT. Rare (sometimes fatal) severe hepatic reactions (eg, fulminant hepatitis, hepatic necrosis, hepatic failure) have occurred with NSAID use; discontinue immediately if clinical signs or symptoms of hepatic disease develop or if systemic manifestations occur.
• Hyperkalemia: NSAID use may increase the risk of hyperkalemia, particularly in the elderly, diabetics, renal disease, and with concomitant use of other agents capable of inducing hyperkalemia (eg, ACE-inhibitors). Monitor potassium closely.
• Renal effects: NSAID use may compromise existing renal function; dose-dependent decreases in prostaglandin synthesis may result from NSAID use, reducing renal blood flow which may cause renal decompensation (usually reversible). Patients with impaired renal function, dehydration, hypovolemia, heart failure, hepatic impairment, those taking diuretics, ACE inhibitors, and the elderly are at greater risk of renal toxicity. Rehydrate patient before starting therapy; monitor renal function closely. Long-term NSAID use may result in renal papillary necrosis and other renal injury.
• Skin reactions: NSAIDs may cause potentially fatal skin adverse events including exfoliative dermatitis, Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN); may occur without warning; discontinue use at first appearance of skin rash (or any other sign of hypersensitivity).
Disease-related concerns:
• Asthma: Contraindicated in patients with aspirin-sensitive asthma; severe and potentially fatal bronchospasm may occur. Use caution in patients with other forms of asthma.
• Coronary artery bypass graft surgery: [US Boxed Warning]: Use is contraindicated in the setting of coronary artery bypass graft (CABG) surgery. Risk of MI and stroke may be increased with use following CABG surgery.
• Hepatic impairment: Use with caution in patients with hepatic impairment; dosage adjustments may be necessary due to extensive hepatic metabolism. Patients with advanced hepatic disease are at an increased risk of GI bleeding with NSAIDs.
• Renal impairment: Avoid use in patients with preexisting renal disease and in patients with advanced renal disease; monitor renal function closely if therapy must be initiated.
Other warnings/precautions:
• Surgical/dental procedures: Withhold for at least 4 to 6 half-lives prior to surgical or dental procedures.
Substrate of CYP2C9 (minor); Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential; Inhibits UGT1A9
5-Aminosalicylic Acid Derivatives: Nonsteroidal Anti-Inflammatory Agents may enhance the nephrotoxic effect of 5-Aminosalicylic Acid Derivatives. Risk C: Monitor therapy
Abrocitinib: Agents with Antiplatelet Properties may enhance the antiplatelet effect of Abrocitinib. Management: Do not use antiplatelet drugs with abrocitinib during the first 3 months of abrocitinib therapy. The abrocitinib prescribing information lists this combination as contraindicated. This does not apply to low dose aspirin (81 mg/day or less). Risk X: Avoid combination
Acalabrutinib: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Acemetacin: May enhance the adverse/toxic effect of Nonsteroidal Anti-Inflammatory Agents. Risk X: Avoid combination
Agents with Antiplatelet Properties (e.g., P2Y12 inhibitors, NSAIDs, SSRIs, etc.): May enhance the antiplatelet effect of other Agents with Antiplatelet Properties. Risk C: Monitor therapy
Alcohol (Ethyl): May enhance the adverse/toxic effect of Nonsteroidal Anti-Inflammatory Agents. Specifically, the risk of GI bleeding may be increased with this combination. Risk C: Monitor therapy
Aliskiren: Nonsteroidal Anti-Inflammatory Agents may diminish the antihypertensive effect of Aliskiren. Nonsteroidal Anti-Inflammatory Agents may enhance the nephrotoxic effect of Aliskiren. Risk C: Monitor therapy
Aminoglycosides: Nonsteroidal Anti-Inflammatory Agents may decrease the excretion of Aminoglycosides. Data only in premature infants. Risk C: Monitor therapy
Aminolevulinic Acid (Systemic): Photosensitizing Agents may enhance the photosensitizing effect of Aminolevulinic Acid (Systemic). Risk X: Avoid combination
Aminolevulinic Acid (Topical): Photosensitizing Agents may enhance the photosensitizing effect of Aminolevulinic Acid (Topical). Risk C: Monitor therapy
Angiotensin II Receptor Blockers: May enhance the adverse/toxic effect of Nonsteroidal Anti-Inflammatory Agents. Specifically, the combination may result in a significant decrease in renal function. Nonsteroidal Anti-Inflammatory Agents may diminish the therapeutic effect of Angiotensin II Receptor Blockers. The combination of these two agents may also significantly decrease glomerular filtration and renal function. Risk C: Monitor therapy
Angiotensin-Converting Enzyme Inhibitors: May enhance the adverse/toxic effect of Nonsteroidal Anti-Inflammatory Agents. Specifically, the combination may result in a significant decrease in renal function. Nonsteroidal Anti-Inflammatory Agents may diminish the antihypertensive effect of Angiotensin-Converting Enzyme Inhibitors. Risk C: Monitor therapy
Anticoagulants: Agents with Antiplatelet Properties may enhance the anticoagulant effect of Anticoagulants. Risk C: Monitor therapy
Apixaban: Nonsteroidal Anti-Inflammatory Agents (Nonselective) may enhance the adverse/toxic effect of Apixaban. Specifically, the risk of bleeding may be increased. Management: A comprehensive risk to benefit assessment should be done for all patients before any concurrent use of apixaban and nonsteroidal anti-inflammatory drugs (NSAIDs). If combined, monitor patients extra closely for signs and symptoms of bleeding. Risk D: Consider therapy modification
Bemiparin: Nonsteroidal Anti-Inflammatory Agents may enhance the anticoagulant effect of Bemiparin. Management: Avoid concomitant use of bemiparin and nonsteroidal anti-inflammatory agents (NSAIDs) due to the increased risk of bleeding. If concomitant use is unavoidable, monitor closely for signs and symptoms of bleeding. Risk D: Consider therapy modification
Bemiparin: Agents with Antiplatelet Properties may enhance the anticoagulant effect of Bemiparin. Management: Avoid concomitant use of bemiparin with antiplatelet agents. If concomitant use is unavoidable, monitor closely for signs and symptoms of bleeding. Risk D: Consider therapy modification
Beta-Blockers: Nonsteroidal Anti-Inflammatory Agents may diminish the antihypertensive effect of Beta-Blockers. Risk C: Monitor therapy
Bile Acid Sequestrants: May decrease the absorption of Nonsteroidal Anti-Inflammatory Agents. Risk C: Monitor therapy
Bisphosphonate Derivatives: Nonsteroidal Anti-Inflammatory Agents may enhance the adverse/toxic effect of Bisphosphonate Derivatives. Both an increased risk of gastrointestinal ulceration and an increased risk of nephrotoxicity are of concern. Risk C: Monitor therapy
Cephalothin: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Cephalothin. Specifically, the risk for bleeding may be increased. Risk C: Monitor therapy
Collagenase (Systemic): Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Collagenase (Systemic). Specifically, the risk of injection site bruising and or bleeding may be increased. Risk C: Monitor therapy
Corticosteroids (Systemic): May enhance the adverse/toxic effect of Nonsteroidal Anti-Inflammatory Agents (Nonselective). Risk C: Monitor therapy
CycloSPORINE (Systemic): Nonsteroidal Anti-Inflammatory Agents may enhance the nephrotoxic effect of CycloSPORINE (Systemic). Nonsteroidal Anti-Inflammatory Agents may increase the serum concentration of CycloSPORINE (Systemic). CycloSPORINE (Systemic) may increase the serum concentration of Nonsteroidal Anti-Inflammatory Agents. Management: Consider alternatives to nonsteroidal anti-inflammatory agents (NSAIDs). Monitor for evidence of nephrotoxicity, as well as increased serum cyclosporine concentrations and systemic effects (eg, hypertension) during concomitant therapy with NSAIDs. Risk D: Consider therapy modification
Dabigatran Etexilate: Nonsteroidal Anti-Inflammatory Agents (Nonselective) may enhance the adverse/toxic effect of Dabigatran Etexilate. Specifically, the risk of bleeding may be increased. Management: A comprehensive risk to benefit assessment should be done for all patients before any concurrent use of dabigatran and nonsteroidal anti-inflammatory drugs (NSAIDs). If combined, monitor patients extra closely for signs and symptoms of bleeding. Risk D: Consider therapy modification
Dasatinib: May enhance the anticoagulant effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Deferasirox: Nonsteroidal Anti-Inflammatory Agents may enhance the adverse/toxic effect of Deferasirox. Specifically, the risk for GI ulceration/irritation or GI bleeding may be increased. Risk C: Monitor therapy
Deoxycholic Acid: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Deoxycholic Acid. Specifically, the risk for bleeding or bruising in the treatment area may be increased. Risk C: Monitor therapy
Desmopressin: Nonsteroidal Anti-Inflammatory Agents may enhance the hyponatremic effect of Desmopressin. Risk C: Monitor therapy
Digoxin: Nonsteroidal Anti-Inflammatory Agents may increase the serum concentration of Digoxin. Risk C: Monitor therapy
Drospirenone-Containing Products: May enhance the hyperkalemic effect of Nonsteroidal Anti-Inflammatory Agents. Risk C: Monitor therapy
Edoxaban: Nonsteroidal Anti-Inflammatory Agents (Nonselective) may enhance the adverse/toxic effect of Edoxaban. Specifically, the risk of bleeding may be increased. Management: A comprehensive risk to benefit assessment should be done for all patients before any concurrent use of edoxaban and nonsteroidal anti-inflammatory drugs (NSAIDs). If combined, monitor patients extra closely for signs and symptoms of bleeding. Risk D: Consider therapy modification
Enoxaparin: Nonsteroidal Anti-Inflammatory Agents may enhance the anticoagulant effect of Enoxaparin. Management: Discontinue nonsteroidal anti-inflammatory agents (NSAIDs) prior to initiating enoxaparin whenever possible. If concomitant administration is unavoidable, monitor closely for signs and symptoms of bleeding. Risk D: Consider therapy modification
Enoxaparin: Agents with Antiplatelet Properties may enhance the anticoagulant effect of Enoxaparin. Management: Discontinue antiplatelet agents prior to initiating enoxaparin whenever possible. If concomitant administration is unavoidable, monitor closely for signs and symptoms of bleeding. Risk D: Consider therapy modification
Eplerenone: Nonsteroidal Anti-Inflammatory Agents may diminish the antihypertensive effect of Eplerenone. Nonsteroidal Anti-Inflammatory Agents may enhance the hyperkalemic effect of Eplerenone. Risk C: Monitor therapy
Heparin: Nonsteroidal Anti-Inflammatory Agents may enhance the anticoagulant effect of Heparin. Management: Decrease the dose of heparin or nonsteroidal anti-inflammatory agents (NSAIDs) if coadministration is required. Risk D: Consider therapy modification
Heparin: Agents with Antiplatelet Properties may enhance the anticoagulant effect of Heparin. Management: Decrease the dose of heparin or agents with antiplatelet properties if coadministration is required. Risk D: Consider therapy modification
Herbal Products with Anticoagulant/Antiplatelet Effects (eg, Alfalfa, Anise, Bilberry): May enhance the adverse/toxic effect of Agents with Antiplatelet Properties. Bleeding may occur. Risk C: Monitor therapy
Herbal Products with Anticoagulant/Antiplatelet Effects (eg, Alfalfa, Anise, Bilberry): May enhance the adverse/toxic effect of Nonsteroidal Anti-Inflammatory Agents. Bleeding may occur. Risk C: Monitor therapy
HydrALAZINE: Nonsteroidal Anti-Inflammatory Agents may diminish the antihypertensive effect of HydrALAZINE. Risk C: Monitor therapy
Ibritumomab Tiuxetan: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Ibritumomab Tiuxetan. Both agents may contribute to impaired platelet function and an increased risk of bleeding. Risk C: Monitor therapy
Ibrutinib: May enhance the adverse/toxic effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Icosapent Ethyl: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Inotersen: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Ketorolac (Nasal): May enhance the adverse/toxic effect of Nonsteroidal Anti-Inflammatory Agents. Risk X: Avoid combination
Ketorolac (Systemic): Nonsteroidal Anti-Inflammatory Agents may enhance the adverse/toxic effect of Ketorolac (Systemic). Risk X: Avoid combination
Levothyroxine: Mefenamic Acid may decrease the protein binding of Levothyroxine. Risk C: Monitor therapy
Limaprost: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Lipid Emulsion (Fish Oil Based): May enhance the adverse/toxic effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Lithium: Nonsteroidal Anti-Inflammatory Agents may increase the serum concentration of Lithium. Management: Consider reducing the lithium dose when initiating a NSAID. Monitor for increased lithium therapeutic/toxic effects if a NSAID is initiated/dose increased, or decreased effects if a NSAID is discontinued/dose decreased. Risk D: Consider therapy modification
Loop Diuretics: Nonsteroidal Anti-Inflammatory Agents may diminish the diuretic effect of Loop Diuretics. Loop Diuretics may enhance the nephrotoxic effect of Nonsteroidal Anti-Inflammatory Agents. Management: Monitor for evidence of kidney injury or decreased therapeutic effects of loop diuretics with concurrent use of an NSAID. Consider avoiding concurrent use in CHF or cirrhosis. Concomitant use of bumetanide with indomethacin is not recommended. Risk D: Consider therapy modification
Macimorelin: Nonsteroidal Anti-Inflammatory Agents may diminish the diagnostic effect of Macimorelin. Risk X: Avoid combination
MetFORMIN: Nonsteroidal Anti-Inflammatory Agents may enhance the adverse/toxic effect of MetFORMIN. Risk C: Monitor therapy
Methotrexate: Nonsteroidal Anti-Inflammatory Agents may increase the serum concentration of Methotrexate. Management: Avoid coadministration of higher dose methotrexate (such as that used for the treatment of oncologic conditions) and NSAIDs. Use caution if coadministering lower dose methotrexate and NSAIDs. Risk D: Consider therapy modification
Methoxsalen (Systemic): Photosensitizing Agents may enhance the photosensitizing effect of Methoxsalen (Systemic). Risk C: Monitor therapy
Mifamurtide: Nonsteroidal Anti-Inflammatory Agents may diminish the therapeutic effect of Mifamurtide. Risk X: Avoid combination
Multivitamins/Fluoride (with ADE): May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Multivitamins/Minerals (with ADEK, Folate, Iron): May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Multivitamins/Minerals (with AE, No Iron): May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Naftazone: May enhance the antiplatelet effect of Nonsteroidal Anti-Inflammatory Agents. Risk C: Monitor therapy
Nonsteroidal Anti-Inflammatory Agents: May enhance the adverse/toxic effect of other Nonsteroidal Anti-Inflammatory Agents. Specifically, the risk for gastrointestinal toxicity is increased. Risk X: Avoid combination
Nonsteroidal Anti-Inflammatory Agents (Topical): May enhance the adverse/toxic effect of Nonsteroidal Anti-Inflammatory Agents. Specifically, the risk of gastrointestinal (GI) toxicity is increased. Management: Coadministration of systemic nonsteroidal anti-inflammatory drugs (NSAIDs) and topical NSAIDs is not recommended. If systemic NSAIDs and topical NSAIDs, ensure the benefits outweigh the risks and monitor for increased NSAID toxicities. Risk D: Consider therapy modification
Obinutuzumab: Agents with Antiplatelet Properties may enhance the adverse/toxic effect of Obinutuzumab. Specifically, the risk of serious bleeding-related events may be increased. Risk C: Monitor therapy
Omacetaxine: Nonsteroidal Anti-Inflammatory Agents may enhance the adverse/toxic effect of Omacetaxine. Specifically, the risk for bleeding-related events may be increased. Risk C: Monitor therapy
Omega-3 Fatty Acids: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Pentosan Polysulfate Sodium: May enhance the adverse/toxic effect of Agents with Antiplatelet Properties. Specifically, the risk of bleeding may be increased by concurrent use of these agents. Risk C: Monitor therapy
Pentoxifylline: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Phenylbutazone: May enhance the adverse/toxic effect of Nonsteroidal Anti-Inflammatory Agents. Risk X: Avoid combination
Porfimer: Photosensitizing Agents may enhance the photosensitizing effect of Porfimer. Risk C: Monitor therapy
Potassium Salts: Nonsteroidal Anti-Inflammatory Agents may enhance the hyperkalemic effect of Potassium Salts. Risk C: Monitor therapy
Potassium-Sparing Diuretics: Nonsteroidal Anti-Inflammatory Agents may diminish the antihypertensive effect of Potassium-Sparing Diuretics. Nonsteroidal Anti-Inflammatory Agents may enhance the hyperkalemic effect of Potassium-Sparing Diuretics. Risk C: Monitor therapy
PRALAtrexate: Nonsteroidal Anti-Inflammatory Agents may increase the serum concentration of PRALAtrexate. More specifically, NSAIDS may decrease the renal excretion of pralatrexate. Management: Avoid coadministration of pralatrexate with nonsteroidal anti-inflammatory drugs (NSAIDs). If coadministration cannot be avoided, closely monitor for increased pralatrexate serum levels or toxicity. Risk D: Consider therapy modification
Probenecid: May increase the serum concentration of Nonsteroidal Anti-Inflammatory Agents. Risk C: Monitor therapy
Prostacyclin Analogues: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Prostaglandins (Ophthalmic): Nonsteroidal Anti-Inflammatory Agents may diminish the therapeutic effect of Prostaglandins (Ophthalmic). Nonsteroidal Anti-Inflammatory Agents may also enhance the therapeutic effects of Prostaglandins (Ophthalmic). Risk C: Monitor therapy
Quinolones: Nonsteroidal Anti-Inflammatory Agents may enhance the neuroexcitatory and/or seizure-potentiating effect of Quinolones. Nonsteroidal Anti-Inflammatory Agents may increase the serum concentration of Quinolones. Risk C: Monitor therapy
Rivaroxaban: Nonsteroidal Anti-Inflammatory Agents (Nonselective) may enhance the adverse/toxic effect of Rivaroxaban. Specifically, the risk of bleeding may be increased. Management: A comprehensive risk to benefit assessment should be done for all patients before any concurrent use of rivaroxaban and nonsteroidal anti-inflammatory drugs (NSAIDs). If combined, monitor patients extra closely for signs and symptoms of bleeding. Risk D: Consider therapy modification
Salicylates: Nonsteroidal Anti-Inflammatory Agents (Nonselective) may enhance the adverse/toxic effect of Salicylates. An increased risk of bleeding may be associated with use of this combination. Nonsteroidal Anti-Inflammatory Agents (Nonselective) may diminish the cardioprotective effect of Salicylates. Salicylates may decrease the serum concentration of Nonsteroidal Anti-Inflammatory Agents (Nonselective). Management: Nonselective NSAIDs may reduce aspirin's cardioprotective effects. Administer ibuprofen 30-120 minutes after immediate-release aspirin, 2 to 4 hours after extended-release aspirin, or 8 hours before aspirin. Risk D: Consider therapy modification
Selective Serotonin Reuptake Inhibitors: May enhance the antiplatelet effect of Nonsteroidal Anti-Inflammatory Agents (Nonselective). Nonsteroidal Anti-Inflammatory Agents (Nonselective) may diminish the therapeutic effect of Selective Serotonin Reuptake Inhibitors. Management: Consider alternatives to NSAIDs. Monitor for evidence of bleeding and diminished antidepressant effects. It is unclear whether COX-2-selective NSAIDs reduce risk. Risk D: Consider therapy modification
Selumetinib: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Serotonin/Norepinephrine Reuptake Inhibitors: May enhance the antiplatelet effect of Nonsteroidal Anti-Inflammatory Agents (Nonselective). Risk C: Monitor therapy
Sincalide: Drugs that Affect Gallbladder Function may diminish the therapeutic effect of Sincalide. Management: Consider discontinuing drugs that may affect gallbladder motility prior to the use of sincalide to stimulate gallbladder contraction. Risk D: Consider therapy modification
Sodium Phosphates: May enhance the nephrotoxic effect of Nonsteroidal Anti-Inflammatory Agents. Specifically, the risk of acute phosphate nephropathy may be enhanced. Management: Consider avoiding this combination by temporarily suspending treatment with NSAIDs, or seeking alternatives to oral sodium phosphate bowel preparation. If the combination cannot be avoided, maintain adequate hydration and monitor renal function closely. Risk D: Consider therapy modification
Tacrolimus (Systemic): Nonsteroidal Anti-Inflammatory Agents may enhance the nephrotoxic effect of Tacrolimus (Systemic). Risk C: Monitor therapy
Tenofovir Products: Nonsteroidal Anti-Inflammatory Agents may enhance the nephrotoxic effect of Tenofovir Products. Management: Seek alternatives to these combinations whenever possible. Avoid use of tenofovir with multiple NSAIDs or any NSAID given at a high dose due to a potential risk of acute renal failure. Diclofenac appears to confer the most risk. Risk D: Consider therapy modification
Tenoxicam: May enhance the adverse/toxic effect of Nonsteroidal Anti-Inflammatory Agents. Risk X: Avoid combination
Thiazide and Thiazide-Like Diuretics: May enhance the nephrotoxic effect of Nonsteroidal Anti-Inflammatory Agents. Nonsteroidal Anti-Inflammatory Agents may diminish the therapeutic effect of Thiazide and Thiazide-Like Diuretics. Risk C: Monitor therapy
Thrombolytic Agents: Agents with Antiplatelet Properties may enhance the anticoagulant effect of Thrombolytic Agents. Risk C: Monitor therapy
Tipranavir: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Tolperisone: Nonsteroidal Anti-Inflammatory Agents may enhance the adverse/toxic effect of Tolperisone. Specifically, the risk of hypersensitivity reactions may be increased. Tolperisone may enhance the therapeutic effect of Nonsteroidal Anti-Inflammatory Agents. Risk C: Monitor therapy
Tricyclic Antidepressants (Tertiary Amine): May enhance the adverse/toxic effect of Nonsteroidal Anti-Inflammatory Agents (Nonselective). Specifically, the risk of major adverse cardiovascular events may be increased. Tricyclic Antidepressants (Tertiary Amine) may enhance the antiplatelet effect of Nonsteroidal Anti-Inflammatory Agents (Nonselective). Risk C: Monitor therapy
Urokinase: Agents with Antiplatelet Properties may enhance the anticoagulant effect of Urokinase. Risk X: Avoid combination
Vancomycin: Nonsteroidal Anti-Inflammatory Agents may increase the serum concentration of Vancomycin. Risk C: Monitor therapy
Verteporfin: Photosensitizing Agents may enhance the photosensitizing effect of Verteporfin. Risk C: Monitor therapy
Vitamin E (Systemic): May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Vitamin K Antagonists (eg, warfarin): Nonsteroidal Anti-Inflammatory Agents (Nonselective) may enhance the anticoagulant effect of Vitamin K Antagonists. Management: Consider alternatives to this combination when possible. If the combination must be used, monitor coagulation status closely and advise patients to promptly report any evidence of bleeding or bruising. Risk D: Consider therapy modification
Zanubrutinib: May enhance the antiplatelet effect of Agents with Antiplatelet Properties. Risk C: Monitor therapy
Nonsteroidal anti-inflammatory drugs may delay or prevent rupture of ovarian follicles. This may be associated with infertility that is reversible upon discontinuation of the medication. Consider discontinuing use in patients having difficulty conceiving or those undergoing investigation of fertility.
Mefenamic acid crosses the placenta (Mackenzie 1985).
The use of nonsteroidal anti-inflammatory drugs (NSAIDs) close to conception may be associated with an increased risk of miscarriage due to cyclooxygenase-2 inhibition interfering with implantation (Bermas 2014; Bloor 2013).
Birth defects have been observed following in utero NSAID exposure in some studies; however, data are conflicting (Bloor 2013). Nonteratogenic effects, including prenatal constriction of the ductus arteriosus, persistent pulmonary hypertension of the newborn, oligohydramnios, necrotizing enterocolitis, renal dysfunction or failure, and intracranial hemorrhage have been observed in the fetus/neonate following in utero NSAID exposure (Bermas 2014; Bloor 2013). Maternal NSAID use may cause fetal renal dysfunction leading to oligohydramnios. Although rare, this may occur as early as 20 weeks' gestation and is more likely to occur with prolonged maternal use. Oligohydramnios may be reversible following discontinuation of the NSAID (Dathe 2019; FDA 2020). In addition, nonclosure of the ductus arteriosus postnatally may occur and be resistant to medical management (Bermas 2014; Bloor 2013).
Maternal use of NSAIDs should be avoided beginning at 20 weeks' gestation. If NSAID use is necessary between 20 and 30 weeks' gestation, limit use to the lowest effective dose and shortest duration possible; consider ultrasound monitoring of amniotic fluid if treatment extends beyond 48 hours and discontinue the NSAID if oligohydramnios is found (FDA 2020). Because NSAIDs may cause premature closure of the ductus arteriosus, product labeling for mefenamic acid specifically states use should be avoided starting at 30 weeks' gestation.
Mefenamic acid may be present in breast milk.
The relative infant dose (RID) of mefenamic acid is 0.92% when calculated using the highest breast milk concentration located and compared to a weight-adjusted maternal dose of 750 mg/day.
In general, breastfeeding is considered acceptable when the RID is <10% (Anderson 2016; Ito 2000).
The RID of mefenamic acid was calculated using a breast milk concentration of 0.66 mcg/mL, providing an estimated infant dose via breast milk of 0.099 mg/kg/day. This milk concentration was obtained following maternal administration of oral mefenamic acid 500 mg followed by 250 mg 3 times a day to 10 lactating women; sampling occurred on postpartum days 2 through 4. Mefenamic acid concentration in breast milk ranged from 0.03 to 0.66 mcg/mL. The total concentration of mefenamic acid and metabolites in breast milk were measured in three patients (seven samples available) and ranged from 0.62 to 1.99 mcg/mL. Mefenamic acid was measurable in infant serum and urine with mean concentrations of 0.08 mcg/mL and 9.8 mcg/mL, respectively. In comparison, maternal serum samples ranged from 0.1 to 3.6 mcg/mL (Buchanan 1968).
Nonopioid analgesics, including nonsteroidal anti-inflammatory drugs (NSAIDs), are preferred for breastfeeding patients who require pain control peripartum or for surgery outside of the postpartum period (ABM [Martin 2018]; ABM [Reece-Stremtan 2017]).
Due to the potential for serious adverse reactions in the breastfeeding infant, the manufacturer recommends a decision be made whether to discontinue breastfeeding or to discontinue the drug, considering the importance of treatment to the mother. Maternal use of NSAIDs should be avoided if the breastfeeding infant has platelet dysfunction, thrombocytopenia, or a ductal-dependent cardiac lesion (ABM [Martin 2018]; ABM [Reece-Stremtan 2017]; Bloor 2013).
CBC, chemistry profile, occult blood loss, and periodic liver function tests; renal function (urine output, serum BUN and creatinine); signs or symptoms of GI bleeding; blood pressure.
Reversibly inhibits cyclooxygenase-1 and 2 (COX-1 and 2) enzymes, which results in decreased formation of prostaglandin precursors; has antipyretic, analgesic, and anti-inflammatory properties.
Other proposed mechanisms not fully elucidated (and possibly contributing to the anti-inflammatory effect to varying degrees) include inhibiting chemotaxis, altering lymphocyte activity, inhibiting neutrophil aggregation/activation, and decreasing proinflammatory cytokine levels.
Absorption: Rapidly absorbed
Distribution: Vd: 1.06 L/kg
Protein binding: >90% to albumin
Metabolism: Hepatic via CYP2C9 to metabolites (activity not known)
Half-life elimination: ~2 hours
Time to peak: 2 to 4 hours
Excretion: Urine (~52%) and feces (~20%) as unchanged drug and metabolites
Renal function impairment: The potential exists for mefenamic acid metabolites to accumulate.
Hepatic function impairment: The potential exists for mefenamic acid metabolites to accumulate.
Capsules (Mefenamic Acid Oral)
250 mg (per each): $17.33 - $29.50
Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.
