Prostate cancer, advanced: Oral: Initial: 360 mg on day 1, followed by 120 mg once daily thereafter (Shore 2020). Gonadotropin-releasing hormone receptor agonist or antagonist therapy is generally continued upon development of metastatic or nonmetastatic castration-resistant disease.
Missed dose: If a dose is missed, administer the missed dose as soon as possible. If the dose was missed by >12 hours, do not take the missed dose and resume with the next scheduled dose. If relugolix therapy is interrupted for >7 days, reinitiate therapy with a loading dose of 360 mg on day 1, followed by 120 mg once daily.
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
CrCl 15 to 89 mL/minute: There are no dosage adjustments provided in the manufacturer's labeling; however, no clinically meaningful differences in relugolix pharmacokinetics were observed in mild to severe renal impairment.
End-stage renal disease (with or without hemodialysis): There are no dosage adjustments provided in the manufacturer's labeling (has not been evaluated).
Mild to moderate impairment (Child-Pugh class A or B): There are no dosage adjustments provided in the manufacturer's labeling; however, no clinically meaningful differences in relugolix pharmacokinetics were observed in mild to moderate hepatic impairment.
Severe impairment (Child-Pugh class C): There are no dosage adjustments provided in the manufacturer's labeling (has not been evaluated).
Refer to adult dosing.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet, Oral:
Orgovyx: 120 mg
No
Oral: Administer at approximately the same time each day, with or without food. Swallow tablets whole; do not crush or chew.
This medication is not on the NIOSH (2016) list; however, it may meet the criteria for a hazardous drug. Relugolix may cause reproductive toxicity, teratogenicity, and has a structural and/or toxicity profile similar to existing hazardous agents.
Use appropriate precautions for receiving, handling, storage, preparation, dispensing, transporting, administration, and disposal. Follow NIOSH and USP 800 recommendations and institution-specific policies/procedures for appropriate containment strategy (NIOSH 2016; USP-NF 2020).
Note: Facilities may perform risk assessment of some hazardous drugs to determine if appropriate for alternative handling and containment strategies (USP-NF 2020). Refer to institution-specific handling policies/procedures.
Prostate cancer, advanced: Treatment of advanced prostate cancer.
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.
>10%:
Endocrine & metabolic: Hot flash (54%), increased serum glucose (44%), increased serum triglycerides (35%)
Gastrointestinal: Constipation (12%), diarrhea (12%, including colitis)
Hematologic & oncologic: Decreased hemoglobin (28%; grades 3/4: <1%)
Hepatic: Increased serum alanine aminotransferase (27%), increased serum aspartate aminotransferase (18%)
Nervous system: Fatigue (26%)
Neuromuscular & skeletal: Musculoskeletal pain (30%)
1% to 10%:
Cardiovascular: Acute myocardial infarction (≤3%), cerebrovascular accident (≤3%)
Dermatologic: Hyperhidrosis
Endocrine & metabolic: Decreased libido, gynecomastia, weight gain
Nervous system: Depression, insomnia
<1%:
Cardiovascular: Cardiac arrhythmia
Genitourinary: Urinary tract infection
Hematologic & oncologic: Hemorrhage
Renal: Acute kidney injury
Frequency not defined:
Cardiovascular: Atrioventricular block, cardiac failure
Endocrine & metabolic: Altered gonadal hormone levels (decreased)
Gastrointestinal: Abdominal pain
Respiratory: Pneumonia
There are no contraindications listed in the manufacturer's labeling.
Concerns related to adverse effects:
• QT/QTc prolongation: Androgen deprivation therapy may prolong the QT/QTc interval. Consider risk versus benefit of androgen deprivation therapy in patients with congenital long QT syndrome, heart failure, frequent electrolyte abnormalities, and concomitant use of medications known to prolong QT interval. Correct electrolyte abnormalities prior to use.
Disease-related concerns:
• Cardiovascular disease: Androgen deprivation therapy may increase the risk for cardiovascular disease (Levine 2010).
• Diabetes: Androgen deprivation therapy may be associated with an increased risk for insulin resistance and diabetes (Keating 2006).
Substrate of CYP2C8 (minor), CYP3A4 (minor), P-glycoprotein/ABCB1 (major); Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential
Asciminib: May increase the serum concentration of P-glycoprotein/ABCB1 Substrates (High risk with Inhibitors). Risk C: Monitor therapy
Erdafitinib: May increase the serum concentration of P-glycoprotein/ABCB1 Substrates (High risk with Inhibitors). Risk C: Monitor therapy
Gallium Ga 68 PSMA-11: Androgen Deprivation Therapy Agents may diminish the therapeutic effect of Gallium Ga 68 PSMA-11. Management: Androgen deprivation therapy (ADT) may result in changes in the uptake of gallium Ga 68 PSMA-11 in prostate cancer. The impact of ADT on the performance of gallium Ga 68 PSMA-11 is unknown, but use of alternative agents should be considered. Risk D: Consider therapy modification
Gilteritinib: May increase the serum concentration of P-glycoprotein/ABCB1 Substrates (High risk with Inhibitors). Risk C: Monitor therapy
Haloperidol: QT-prolonging Agents (Indeterminate Risk - Caution) may enhance the QTc-prolonging effect of Haloperidol. Risk C: Monitor therapy
Indium 111 Capromab Pendetide: Antigonadotropic Agents may diminish the diagnostic effect of Indium 111 Capromab Pendetide. Risk X: Avoid combination
Inducers of CYP3A4 (Moderate) and P-glycoprotein: May decrease the serum concentration of Relugolix. Risk C: Monitor therapy
Inducers of CYP3A4 (Strong) and P-glycoprotein: May decrease the serum concentration of Relugolix. Management: Avoid use of relugolix with drugs that are both strong CYP3A4 and P-glycoprotein (P-gp) inducer. If combined, increase the dose of relugolix to 240 mg once daily. Reduce back to 120 mg daily once the combined inducer is discontinued. Risk D: Consider therapy modification
Lasmiditan: May increase the serum concentration of P-glycoprotein/ABCB1 Substrates (High risk with Inhibitors). Risk X: Avoid combination
Lumacaftor and Ivacaftor: May increase the serum concentration of P-glycoprotein/ABCB1 Substrates (High risk with Inhibitors or Inducers). Lumacaftor and Ivacaftor may decrease the serum concentration of P-glycoprotein/ABCB1 Substrates (High risk with Inhibitors or Inducers). Risk C: Monitor therapy
Mitapivat: May increase the serum concentration of P-glycoprotein/ABCB1 Substrates (High risk with Inhibitors). Risk C: Monitor therapy
P-glycoprotein/ABCB1 Inhibitors: May increase the serum concentration of Relugolix. Management: Avoid coadministration of relugolix with oral P-gp inhibitors whenever possible. If combined, take relugolix at least 6 hours prior to the P-gp inhibitor and monitor patients more frequently for adverse reactions. Risk D: Consider therapy modification
Piflufolastat F18: Androgen Deprivation Therapy Agents may diminish the diagnostic effect of Piflufolastat F18. Management: Androgen deprivation therapy (ADT) may result in changes in the uptake of piflufolastat F18 in prostate cancer. The impact of ADT on the performance of piflufolastat F18 is unknown, but use of alternative agents should be considered. Risk D: Consider therapy modification
QT-prolonging Agents (Highest Risk): QT-prolonging Agents (Indeterminate Risk - Caution) may enhance the QTc-prolonging effect of QT-prolonging Agents (Highest Risk). Management: Monitor for QTc interval prolongation and ventricular arrhythmias when these agents are combined. Patients with additional risk factors for QTc prolongation may be at even higher risk. Risk C: Monitor therapy
Patients with partners who may become pregnant should use effective contraception during therapy and for 2 weeks after the last dose of relugolix. Based on the mechanism of action, male fertility may be impaired.
Based on the mechanism of action and data from animal reproduction studies, in utero exposure to relugolix may cause fetal harm and loss of pregnancy.
It is unknown if relugolix is present in breast milk.
Prostate-specific antigen at baseline and periodically; serum testosterone levels (if clinically necessary). Consider periodic monitoring of ECGs and electrolytes. Monitor adherence.
Relugolix is a nonpeptide gonadotropin-releasing hormone (GnRH) antagonist that competitively binds to pituitary GnRH receptors, blocking the receptor and decreasing secretion of luteinizing hormone and follicle stimulation hormone, resulting in decreased testosterone levels.
Onset: Testosterone concentrations at castrate levels (<50 ng/dL) were observed by day 4 in over half of patients; almost all maintained castrate testosterone levels through 48 weeks.
Protein binding: 68% to 71% (primarily to albumin).
Metabolism: Primarily hepatic via CYP3A and to a lesser extent by CYP2C8.
Bioavailability: ~12%.
Half-life elimination: Mean effective half-life: 25 hours; Mean terminal elimination half-life: ~61 hours.
Time to peak: 2.25 hours (range: 0.5 to 5 hours).
Excretion: Feces: ~81% (4.2% unchanged); Urine: ~4% (2.2% unchanged).
Clearance: Mean: 29.4 L/hour; renal: 8 L/hour.
Tablets (Orgovyx Oral)
120 mg (per each): $98.26
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