Metolazone oral
- Drugs List
- Therapeutic Indications
- Dosage
- Contraindications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
- Monograph
Presentation
Oral formulations of metolazone.
Drugs List
Therapeutic Indications
Uses
Hypertension - mild to moderate
Oedema due to congestive heart failure
Oedema due to renal disease
Unlicensed Uses
Forced diuresis
Oedema due to hepatic disease
Pulmonary oedema
Dosage
The bioavailability of some brands of tablets differs significantly from other metolazone products. Therefore, product literature must be consulted to determine the dosage before switching the patient to a different metolazone product.
Adults
Oedema due to kidney disease
Initial: 2.5mg once daily.
Maintenance: Dose may be increased up to 5mg depending on the patients response. It is recommended to reduce the maintenance dose if possible once the desired therapeutic effect has been achieved.
Oedema due to congestive heart failure
Initial: 2.5mg once daily.
Maintenance: Dose may be increased up to 5mg depending on the patients response. It is recommended to reduce the maintenance dose if possible once the desired therapeutic effect has been achieved.
Hypertension- mild to moderate
Initial: 2.5mg once daily.
Maintenance: Dose may be increased up to 5mg depending on the patients response. It is recommended to reduce the maintenance dose if possible once the desired therapeutic effect has been achieved.
Children
Oedema (unlicensed)
Children aged 12 to 18 years
5mg to 10mg each morning daily.
Dose may be increased to 5mg to 10mg twice daily in cases of resistant oedema.
Children aged 1 month to 12 years
100 to 200micrograms/kg bodyweight 1 to 2 times daily.
Contraindications
Neonates under 1 month
Addison's disease
Anuria
Breastfeeding
Galactosaemia
Hepatic coma
Hypercalcaemia
Hyponatraemia
Pre-coma associated with hepatic cirrhosis
Pregnancy
Refractory hypokalaemia
Severe electrolyte imbalance
Symptomatic hyperuricaemia
Precautions and Warnings
Children 1 month to 18 years
Elderly
Diabetes mellitus
Electrolyte imbalance
Glucose-galactose malabsorption syndrome
Gout
History of gout
Lactose intolerance
Porphyria
Severe hepatic impairment
Severe renal impairment
Systemic lupus erythematosus
May cause hepatic encephalopathy in patients with hepatic disease
May exacerbate or activate systemic lupus erythematosus
Advise ability to drive/operate machinery may be affected by side effects
Contains lactose
Consider the addition of a potassium sparing agent to correct hypokalaemia
Diabetic control may need adjustment
Monitor blood glucose periodically
Monitor fluid and electrolyte status
Monitor renal function regularly
Monitor serum potassium regularly
Progressive renal disease: discontinue if azotaemia and oliguria occurs
May precipitate diabetes mellitus
May precipitate gout
Discontinue before parathyroid function tests
May affect results of some laboratory tests
Discontinue if symptoms of acute angle closure glaucoma occur
Bioavailability differs with preparations;caution on changing formulations
Maintain treatment at the lowest effective dose
Advise patient not to take NSAIDs unless advised by clinician
Hypotensive effects may be potentiated by alcohol
Patients should have serum electrolytes monitored regularly to observe signs of electrolyte imbalance. Symptoms that may indicate electrolyte imbalance include dry mouth, weakness, lethargy, drowsiness, restlessness, muscle cramps or pains, muscular fatigue, hypotension, oliguria, tachycardia and gastrointestinal disturbances such as nausea and vomiting.
Pregnancy and Lactation
Pregnancy
Metolazone is contraindicated during pregnancy.
The manufacturer does not recommend using metolazone during pregnancy. The manufacturer states that metolazone may be used in the last trimester if absolutely necessary but it is recommended the lowest possible dose is used. Available reports indicate that thiazide diuretics, such as metolazone, may pass over to the foetus, causing electrolyte imbalance. Neonatal thrombocytopenia, bone marrow suppression, jaundice, hypoglycaemia and reduced placental perfusion have also been reported.
Exposure to metolazone may also cause stimulation of labour, uterine inertia, and meconium staining.
Lactation
Metolazone is contraindicated during breastfeeding.
Use of metolazone when breastfeeding is contraindicated by the manufacturer. Metolazone is present in human breast milk in levels which may cause adverse effects in the breastfed infant, even at therapeutic doses. Large doses are also suspected to decrease breast milk production and therefore other diuretics in low doses are preferred over metolazone (LactMed 2021).
Side Effects
Abdominal pain
Acute renal insufficiency
Agranulocytosis
Allergic reaction
Anaphylactic reaction
Anorexia
Apathy
Aplastic anaemia
Azotaemia
Bloating
Blurred vision (transient)
Chest pain
Chills
Choroidal effusion
Confusion
Constipation
Dehydration
Depression
Dermatitis
Diarrhoea
Dizziness
Drowsiness
Elevated serum LDL cholesterol
Elevated triglyceride levels
Erectile dysfunction
Exanthema
Fatigue
Glycosuria
Gout
Headache
Hepatic encephalopathy
Hepatitis
Hypercalcaemia
Hyperglycaemia
Hyperuricaemia
Hypochloraemia
Hypochloraemic alkalosis
Hypokalaemia
Hypomagnesaemia
Hyponatraemia
Hypophosphataemia
Hypotension
Increase in haematocrit
Insomnia
Intrahepatic cholestasis
Joint pain
Lethargy
Leukopenia
Muscle pain
Muscular cramps
Nausea
Neuropathy
Oliguria
Orthostatic hypotension
Palpitations
Pancreatitis
Paraesthesia
Photosensitivity
Purpura
Restlessness
Seizures
Serum creatinine increased
Serum urea increased
Stevens-Johnson syndrome
Syncope
Tachycardia
Thrombocytopenia
Toxic epidermal necrolysis
Urticaria
Vasculitis
Venous thrombosis
Vertigo
Visual field defects
Vomiting
Weakness
Effects on Laboratory Tests
Due to the effects of metolazone on serum calcium levels, metolazone should be discontinued before carrying out tests for parathyroid function.
An altered plasma lipid profile has been observed when taking thiazide-like diuretics.
Overdosage
It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.
The following number will direct the caller to the relevant local centre (0844) 892 0111
Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Further Information
Last Full Review Date: May 2022
Reference Sources
Summary of Product Characteristics: Xaqua 5mg Tablets. Renascience Pharma Ltd. Revised February 2021.
NICE Evidence Services Available at: www.nice.org.uk Last accessed: 10 May 2022
US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
Available at: https://www.ncbi.nlm.nih.gov/books/NBK501922/
Metolazone. Last revised: 18 January 2021
Last accessed: 09 May 2022
Medscape UK | Univadis prescription drug monographs & interactions are based on FDB Multilex Content
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