Ibsrela

1145

1144.306793

WYD79216A6

DTXSID40154016

A - Alimentary tract and metabolism

235

Practically insoluble

|Warning|H371 (100%): May cause damage to organs [Warning Specific target organ toxicity, single exposure]|P260, P264, P270, P309+P311, P405, and P501|The GHS information provided by 1 company from 1 notification to the ECHA C&L Inventory.

Symptoms of overdose are likely to be consistent with tenapanor's adverse effect profile, and may therefore include gastrointestinal effects such as diarrhea. Dehydration may occur depending on duration and severity of diarrhea. No specific management strategies have been proposed in cases of overdose.

Both tenapanor and its principle metabolite, M1, are highly plasma protein bound at approximately 99% and 97%, respectively. The specific proteins to which tenapanor and its metabolite binds have yet to be elucidated.

Tenapanor is indicated for the treatment of constipation-predominant irritable bowel syndrome (IBS-C) in adults. It is also currently being investigated as a treatment for hyperphosphatemia in chronic kidney disease patients undergoing dialysis (NCT02081534 and NCT02675998).

Through the inhibition of dietary sodium absorption tenapanor causes an increase in water secretion into the intestines, thereby decreasing transit time and softening stool consistency.

Tenapanor undergoes very minimal systemic absorption following oral administration. During clinical trials, plasma concentrations were below the limit of quantitation (i.e. less than 0.5 ng/mL) in the majority of samples from healthy subjects - for this reason, typical pharmacokinetic values related to absorption such as AUC and C_max were unable to be ascertained. The effects of tenapanor are greatest when administered 5 to 10 minutes before meals.|Following administration of a radio labeled dose of tenapanor, 70% of the radioactivity was excreted in the feces within 120 hours of administration and 79% within 240 hours. Approximately 65% of the total dose is excreted as unchanged parent drug within 144 hours of administration. Only 9% of the administered dose was found in the urine, existing primarily as metabolites. Tenapanor's M1 metabolite is excreted unchanged in the urine and accounts for approximately 1.5% of the total dose within 144 hours of administration.

The majority of tenapanor's metabolism to its primary metabolite, M1, is catalyzed via CYP3A4/5. Exposure of tenapanor to hepatic CYP enzymes is likely limited due to its minimal systemic absorption, so its metabolism may be due to intestinal CYP enzyme activity. The M1 metabolite of tenapanor is a P-glycoprotein substrate and, in contrast to its parent drug, can be detected in plasma, reaching a C_max of approximately 15 ng/mL at steady state. It is not considered active against NHE3.

Tenapanor's FDA label states that its half-life could not be determined during clinical trials due to its minimal systemic absorption resulting in plasma concentrations below the limit of quantitation (i.e. less than 0.5 ng/mL).

Tenapanor is a locally-acting small molecule inhibitor of the sodium/hydrogen exchanger isoform 3 (NHE3), an antiporter expressed on the apical surface of enterocytes in the small intestine and colon which is involved in sodium-fluid homeostasis. By inhibiting this antiporter tenapanor causes retention of sodium within the lumen of the intestine - this results in an osmotic gradient that draws water into the lumen and softens stool consistency. There is some evidence that tenapanor can inhibit the uptake of dietary phosphorus in the gastrointestinal tract, though the exact mechanism of this activity has yet to be elucidated.

AZD1722

Human Drugs -> FDA Approved Drug Products with Therapeutic Equivalence Evaluations (Orange Book) -> Active Ingredients