Irritable bowel syndrome with constipation: Oral: 50 mg twice daily.
Missed dose: If a dose is missed, skip the missed dose and administer the next dose at the regular time. Do not administer 2 doses at the same time.
eGFR >30 mL/minute/1.73 m2: No dosage adjustment necessary.
eGFR <30 mL/minute/1.73 m2: There are no dosage adjustments provided in the manufacturer's labeling (has not been studied).
There are no dosage adjustments provided in the manufacturer's labeling (has not been studied).
Refer to adult dosing.
Severe diarrhea: Discontinue treatment.
No
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet, Oral:
Ibsrela: 50 mg
Not available in the US
Oral: Administer immediately prior to breakfast or the first meal of the day and immediately prior to dinner. Swallow whole; do not chew or crush.
Irritable bowel syndrome with constipation: Treatment of irritable bowel syndrome with constipation in adults.
Other safety concerns:
ALERT: Canadian Boxed Warning: Health Canada-approved labeling includes a boxed warning. See Warnings/Precautions section for a concise summary of this information. For verbatim wording of the boxed warning, consult the product labeling.
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.
>10%: Gastrointestinal: Diarrhea (15%; severe diarrhea: 3%)
1% to 10%:
Gastrointestinal: Abdominal distension (3%), abnormal bowel sounds (1%), flatulence (3%)
Nervous system: Dizziness (1%)
<1%:
Endocrine & metabolic: Decreased serum bicarbonate, dehydration, hyperkalemia, increased thirst
Gastrointestinal: Abdominal tenderness, bowel urgency, fecal incontinence, gastroesophageal reflux disease, viral gastroenteritis, vomiting
Hematologic & oncologic: Rectal hemorrhage
Hypersensitivity to tenapanor or any component of the formulation; patients <6 years of age; known or suspected mechanical GI obstruction.
Concerns related to adverse effects:
• Diarrhea: May cause diarrhea; discontinue and rehydrate if severe diarrhea occurs.
Disease-related concerns:
• Renal impairment: May increase the risk for adverse reactions, including diarrhea and hyperkalemia (requiring hospitalization).
Special populations:
• Pediatric patients: [Canadian Boxed Warning]: Tenapanor is contraindicated in patients <6 years of age. The use of tenapanor in patients between 6 to 18 years of age is not recommended. In nonclinical studies in young juvenile rats (approximate human age equivalent of <2 years of age), administration of tenapanor caused decreased body weight and deaths presumed to be due to dehydration.
Substrate of CYP3A4 (minor); Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential
There are no known significant interactions.
Administration 5 to 10 minutes before a meal increased the 24-hour stool sodium excretion compared to administration in the fasting state.
Pregnancy outcome information is limited from animal reproduction studies due to maternal toxicity at some doses. Patients who could become pregnant were not included in the initial clinical trials (Chey 2020). Tenapanor has limited systemic absorption following oral administration.
It is not known if tenapanor is present in breast milk. However, tenapanor has limited systemic absorption following oral administration.
Frequency of bowel movements; signs and symptoms of dehydration in patients with diarrhea; serum potassium in patients with renal impairment.
Tenapanor is a sodium/hydrogen exchanger 3 inhibitor, which acts locally to reduce sodium absorption from the small intestine and colon. Reduced sodium absorption results in increased intestinal lumen water secretion, accelerating intestinal transit time, and softening stool consistency. Tenapanor also decreases intestinal permeability and visceral hypersensitivity in animal models, which may reduce abdominal pain.
Absorption: Minimal.
Protein binding: ~99%.
Metabolism: Hepatic via CYP3A4/5 primarily to inactive metabolite M1.
Excretion: Feces (~79% as unchanged drug); urine (~9% as metabolites).
