Formulary
Metolazone: Indications, Dosing, Side Effects and Interactions
Metolazone clinical drug profile including indications, dosing, side effects, cautions and interactions.
MedNext Academy | 5 min read
Metolazone: Indications, Dosing, Side Effects and Interactions
Metolazone clinical drug profile including indications, dosing, side effects, cautions and interactions.
Indications and dose
**Oedema in congestive heart failure [using Xaqua tablets],Oedema in renal disease [using Xaqua tablets],Hypertension [using Xaqua tablets]**
- **Adult** (By Mouth): Initially 2.5 mg once daily, increased if necessary to 5 mg once daily.
**Oedema [using metolazone preparations with different bioavailability to Xaqua tablets]**
- **Adult** (By Mouth): 5-10 mg daily, dose to be taken in the morning; increased if necessary to 20 mg daily, dose to be taken in the morning, dose increased in resistant oedema; maximum 80 mg per day.
**Hypertension [using metolazone preparations with different bioavailability to Xaqua tablets]**
- **Adult** (By Mouth): Initially 5 mg daily, dose to be taken in the morning; maintenance 5 mg once daily on alternate days, dose to be taken in the morning.
**Oedema resistant to loop diuretics in heart failure, renal disease and hepatic disease (under expert supervision), Pulmonary oedema (under expert supervision), Adjunct to loop diuretics to induce diuresis (under expert supervision) for metolazone**
- **Child 1 month-11 years** (By mouth): 100-200 micrograms/kg 1-2 times a day, dosing recommendations for children are based on metolazone preparations with different bioavailability to Xaqua tablets (licensed for use in adults).
- **Child 12-17 years** (By mouth): 5-10 mg once daily, dose to be taken in the morning, dose can be increased to twice daily in resistant oedema, if necessary. Dosing recommendations for children are based on metolazone preparations with different bioavailability to Xaqua tablets (licensed for use in adults).
Cautions
For all thiazides and related diuretics Diabetes; gout; risk of hypokalaemia; systemic lupus erythematosus Cautions, further information Existing conditions Thiazides and related diuretics can exacerbate diabetes, gout, and systemic lupus erythematosus. Potassium loss Hypokalaemia can occur with thiazides and related diuretics. Hypokalaemia is dangerous in severe cardiovascular disease and in patients also being treated with cardiac glycosides. Often the use of potassium-sparing diuretics avoids the need to take potassium supplements. In hepatic impairment, hypokalaemia caused by diuretics can precipitate encephalopathy. Elderly Lower initial doses of diuretics may be necessary in the elderly because they are particularly susceptible to the side-effects. The dose should then be adjusted according to renal function. M Screening Tool of Older Persons' potentially inappropriate Prescriptions (STOPP) criteria to aid medication reviews (see Prescribing in the elderly for information). Potentially inappropriate: with current significant hypokalaemia (serum potassium less than 3 mmol/L), hyponatraemia (serum sodium less than 130 mmol/L), or hypercalcaemia (corrected serum calcium greater than 2.65 mmol/L)-contra-indicated; hypokalaemia, hyponatraemia, and hypercalcaemia can be precipitated by a thiazide diuretic with a history of gout (gout can be precipitated by a thiazide diuretic) Cautions For metolazone Acute porphyrias
Contraindications
For all thiazides and related diuretics Addison's disease; hypercalcaemia; hyponatraemia; refractory hypokalaemia; symptomatic hyperuricaemia
Side effects
For all thiazides and related diuretics Common or very common Alkalosis hypochloraemic; constipation; diarrhoea; dizziness; electrolyte imbalance; erectile dysfunction; fatigue; headache; hyperglycaemia; hyperuricaemia; nausea; postural hypotension; skin reactions; vomiting Uncommon Agranulocytosis; aplastic anaemia; leucopenia; pancreatitis; photosensitivity reaction; thrombocytopenia Rare or very rare Paraesthesia Side-effects For metolazone Common or very common Azotaemia; glycosuria; hypotension; muscle complaints Uncommon Arthralgia; gout; vasculitis Rare or very rare Apathy; appetite decreased; asthenia; chest pain; chills; confusion; dehydration; drowsiness; gastrointestinal discomfort; haemoconcentration; hepatic disorders; hepatic encephalopathy; hypoplastic anaemia; palpitations; peripheral neuropathy; psychotic depression; renal impairment; restlessness; seizure; severe cutaneous adverse reactions (SCARs); syncope; tachycardia; venous thrombosis; vertigo; vision blurred
Interactions
**Severe interactions:**
- Loop Diuretics (e.g.
**Other interactions (16):**
- Accordingly, it is advisable to discontinue metolazone tablets three days before elective surgery.
- Cyclosporine Concurrent administration of metolazone and cyclosporine may lead to an increase in serum creatinine.
- Alcohol, barbiturates and narcotics Alcohol, barbiturates and narcotics may potentiate orthostatic hypotension which may occur during treatment with metolazone.
- Antidiabetic medicinal products (oral agents and insulins) Dosage adjustment of the antidiabetic medicinal product may be required (see section 4.4).
- Corticosteroids and ACTH Corticosteroids and ACTH may increase the risk of hypokalaemia and increase salt and water retention.
- Sotalol ) Hypokalaemia associated with thiazide therapy may increase the risk of sotalol- induced arrhythmia (syncope, prolonged QT interval).
Pregnancy
For all thiazides and related diuretics Thiazides and related diuretics should not be used to treat gestational hypertension. They may cause neonatal thrombocytopenia, bone marrow suppression, jaundice, electrolyte disturbances, and hypoglycaemia; placental perfusion may also be reduced. Stimulation of labour, uterine inertia, and meconium staining have also been reported.
Breast feeding
Specialist sources indicate that levels in milk have not been determined, but are likely to be too low to affect the infant. Large doses may suppress lactation.
Hepatic impairment
For all thiazides and related diuretics In general, manufacturer advises caution in mild to moderate impairment; avoid in severe impairment. Hepatic impairment For Xaqua Caution in severe impairment. M
Renal impairment
For all thiazides and related diuretics In general, manufacturers advise caution in mild to moderate impairment (risk of electrolyte imbalance and reduced renal function); avoid in severe impairment (ineffective if creatinine clearance less than 30 mL/minute). See Prescribing in renal impairment . Renal impairment For metolazone See Prescribing in renal impairment . Manufacturer advises metolazone remains effective if eGFR is less than 30 mL/minute/1.73 m 2 but is associated with a risk of excessive diuresis.
Medicinal forms
Tablet
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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