Tolvaptan
Diuretic · Vasopressin antagonist
Indications
Treatment of clinically significant hypervolaemic and euvolemic hyponatraemia (serum sodium and has resisted correction with fluid restriction), including patients with heart failure and Syndrome of Inappropriate Antidiuretic Hormone (SIADH).
Dosage
Adults: 15 mg once daily. Dosage may be increased at intervals =24 hrs to 30 mg once daily, and to a max of 60 mg once daily as needed to raise serum sodium. Children: Not recommended.
Adverse Effects
Constipation, dry mouth, thirst, asthenia, polyuria or pollakiuria and hyperglycaemia.
Risk Factor (Pregnancy/Lactation)
Pregnancy: Contraindicated in pregnancy. Lactation: Contraindicated or not recommended. Contraindications: Autosomal dominant polycystic kidney disease. Patients unable to respond to thirst. Hypovolaemic hyponatraemia. Anuria. Underlying hepatic disease. Precautions: Hepatic injury. Dehydration and hypovolaemia. Monitor serum potassium in patients with potassium >5 mEq/L or on drugs known to increase potassium. Urinary outflow obstruction.
Interactions
Moderate to strong CYP3A inhibitors (e.g. ketoconazole, fluconazole, grapefruit juice), hypertonic saline, V2-receptor agonists (e.g. desmopressin); avoid. Monitor serum potassium during concomitant treatment with: Angiotensin receptor blockers, angiotensin converting enzyme inhibitors, potassium sparing diuretics. CYP3A4 inducers (e.g. Rifampin). Digoxin.
Advice to Patient
Report if you experience any of these symptoms during treatment: Trouble speaking, swallowing trouble or feeling like food or liquid gets stuck while swallowing, drowsiness, confusion, mood changes, trouble controlling body movement (involuntary movement) and weakness in muscles of the arms and legs, seizures, loss of appetite, nausea, vomiting, fever, feeling unwell, unusual tiredness, itching, yellowing of the skin or the whites of the eyes (jaundice), unusual darkening of the urine, right upper stomach area pain or discomfort. Lactating females must avoid nursing babies during treatment. Keep yourself hydrated during treatment. Avoid grapefruit juice during treatment.
Pharmacokinetics
Bioavailability: Absolute: 30 mg dose: 56%. Metabolism: Hepatic. Time to peak: 2-4 hrs.
Brands with this active ingredient
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