Products
Tenapanor was approved in the United States in tablet form in 2019 (Ibsrela).
Structure and properties
Tenapanor (C50H66Cl4N8O10S2, Mr = 1145 g/mol) is present in the drug as tenapanor hydrochloride, a white to light brown, amorphous, and hygroscopic substance that is practically insoluble in water. Because of its high molecular mass and polar surface area (PSA), the drug is poorly absorbed and excreted mainly in the stool.
Effects
Tenapanor counteracts constipation in irritable bowel syndrome. The effects are due to inhibition of sodium/hydrogen exchanger 3 (NHE3), an antiporter found on the apical surface of the small and large intestine and responsible for the absorption of sodium. Inhibition of the transporter increases the sodium concentration in the intestinal lumen and increases the secretion of water into the intestine. This speeds intestinal transit and softens stool. Tenapanor also reduces visceral hypersensitivity and has an antinociceptive effect.
Indications
For the treatment of irritable bowel syndrome with constipation (IBS-C).
Dosage
According to the prescribing information. Tablets are taken about 5 to 10 minutes before breakfast (or the first meal) and before dinner.
Contraindications
- Hypersensitivity
- Children under 6 years of age (risk of dehydration).
- Gastrointestinal obstruction of unknown cause or with a mechanical cause.
For complete precautions, see the drug label.
Adverse effects
The most common possible adverse effects include diarrhea, abdominal distension, flatulence, and dizziness.
