Metolazone

Source: US FDA prescribing information via openFDA/DailyMed for Metolazone tablets (Bryant Ranch Prepack, label date 2024-12-24, https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=194df449-f51d-462b-a916-d892e1cf1217). NO UK SPC POSOLOGY WAS AVAILABLE IN THIS BUNDLE — the dose above is US labelling and must be verified against the UK SPC before publication. Effective dosage should be individualised according to indication and patient response; titrate to gain an initial therapeutic response and then to the minimal dose that maintains it. OEDEMA: the time to effect of the initial dose may vary; diuresis and saluresis usually begin within one hour and persist for 24 hours or longer. Once the desired effect is obtained it may be advisable to reduce the dose. Daily dose depends on severity, sodium intake and responsiveness; changes should follow thorough clinical and laboratory evaluation. More careful dose adjustment may be necessary if antihypertensive drugs or other diuretics are given concurrently. For patients who tend to experience paroxysmal nocturnal dyspnoea a larger dose may be advisable to prolong diuresis and saluresis over a full 24 hours. HYPERTENSION: the interval to effect may vary from three or four days to three to six weeks; adjust doses at appropriate intervals for maximum therapeutic effect. FORMULATION WARNING (as stated in the label): formulations of metolazone are not interchangeable — for patients being switched from Zaroxolyn tablets or other formulations sharing its slow and incomplete bioavailability to Mykrox, the dose should be determined by titration starting at one tablet (0.5 mg) once daily, increasing to two tablets (1 mg) once daily if needed. Confirm which formulation is being prescribed. PAEDIATRIC (label wording, not a recommended regimen): safety and effectiveness in paediatric patients have not been established in controlled clinical trials; there is limited experience in children with congestive heart failure, hypertension, bronchopulmonary dysplasia, nephrotic syndrome and nephrogenic diabetes insipidus, in whom doses used generally ranged from 0.05 mg/kg to 0.1 mg/kg once daily, with variable response; prolonged use beyond a few days was generally associated with no further benefit and is not recommended. Limited experience with metolazone plus furosemide in children with furosemide-resistant oedema — some benefited, others had an exaggerated response with hypovolaemia, tachycardia and orthostatic hypotension requiring fluid replacement; severe hypokalaemia was reported and diuresis tended to persist for up to 24 hours after stopping. Close clinical and laboratory monitoring of all children treated with diuretics is indicated. Verify any under-18 use against a children's formulary. §4.5-equivalent drug interactions section was not retrieved in this bundle; the adverse reactions section was truncated at the source-fetch limit.