Polyene Antifungal Pregnancy: Safety in pregnancy not established; use only if possible benefits outweigh potential risks to mother and fetus. Unknown whether excreted in breast milk — weigh benefit/risk of breastfeeding.

Amphotericin B

Brand names: AmBisome (liposomal), Fungizone (conventional)

Amphotericin B is a polyene antifungal used for serious systemic and invasive fungal infections, available in conventional and lipid-based formulations.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 3 to 5 mg/kg of body weight daily (liposomal formulation)

Route: IV infusion over 30-60 minutes

Frequency: Once daily for a minimum of 14 days

Max: Up to 10 mg/kg/day used in mucormycosis (limited safety/efficacy data above 5 mg/kg)

FORMULATION-CRITICAL: this SPC is for the LIPOSOMAL product (Amphotericin B Gilead liposomal, previously AmBisome). Different amphotericin products (sodium deoxycholate, liposomal, lipid complex) are NOT equivalent in pharmacodynamics, pharmacokinetics or dosing and must not be used interchangeably — verify trade name, common name and dose before administration (risk of under-dose if a liposomal dose is given at a deoxycholate rate). Treatment of mycoses: 3-5 mg/kg/day for min 14 days, adjusted to each patient. Mucormycosis: starting dose 5-10 mg/kg/day (10 mg/kg/day if brain involvement or solid-organ transplant); courses of 6-8 weeks commonly used. HIV-associated cryptococcal meningitis: single 10 mg/kg dose on day 1 with daily flucytosine 100 mg/kg + fluconazole 1200 mg for 14 days. Visceral leishmaniasis: total dose 21.0-30.0 mg/kg given over 10-21 days. Empirical treatment of febrile neutropenia: 3-5 mg/kg/day. Every dose should be infused over 30-60 minutes with close monitoring (anaphylaxis/anaphylactoid reactions can occur at any point).

Paediatric dose

Route: IV infusion

Frequency: Once daily

UK SPC does not give a distinct paediatric per-kg regimen. US FDA label (fallback) states paediatric patients age 1 month to 16 years have received liposomal amphotericin B at doses comparable to adults on a per-kilogram basis with no dosage adjustment required; safety/effectiveness below 1 month of age not established. Verify against a children's formulary.

Dose adjustments

Renal

Substantially less nephrotoxic than conventional amphotericin B but renal adverse reactions may still occur; monitor serum electrolytes (esp. potassium and magnesium), renal, hepatic and haematopoietic function at least weekly. If clinically significant reduction in renal function occurs, consider dose reduction, treatment interruption or discontinuation.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substance or to any of the excipients (unless the condition is life-threatening and amenable only to this therapy, in the physician's opinion)

Side effects

Hypokalaemia (very common)
Nausea, vomiting (very common)
Rigors, pyrexia (very common)
Hyponatraemia, hypocalcaemia, hypomagnesaemia, hyperglycaemia, hyperkalaemia (common)
Headache, tachycardia, hypotension, dyspnoea, increased creatinine and blood urea (common)

Interactions

Antineoplastic agents — may enhance potential for renal toxicity, bronchospasm and hypotension (US label)
Corticosteroids and corticotropin (ACTH) — may potentiate hypokalaemia (US label)
Digitalis glycosides — hypokalaemia may potentiate digitalis toxicity; monitor serum potassium (US label)
Flucytosine — concurrent use may increase flucytosine toxicity (US label)
Azoles (e.g. ketoconazole, miconazole, fluconazole) — may induce fungal resistance to amphotericin B (US label)

Clinical monograph

How it works

It binds ergosterol in the fungal cell membrane, forming pores that increase permeability and cause leakage of intracellular contents and cell death.

Prescribing in practice

Nephrotoxicity and electrolyte disturbance (notably hypokalaemia and hypomagnesaemia) are major risks, so renal function and electrolytes must be monitored closely.
Different formulations are not interchangeable and prescriptions should specify the exact product to avoid serious dosing errors.
Infusion-related reactions are common, and a test dose and supportive measures may be used as directed by the SPC.

Monitoring

Monitor renal function, serum electrolytes (particularly potassium and magnesium), full blood count and liver function during therapy.

Counselling the patient

Tell the team if you develop fever, chills, breathlessness or other symptoms during the infusion.
Regular blood tests are needed to check your kidneys and salts.
Report reduced urine output or muscle weakness.

Evidence & guidelines

Amphotericin B remains a recommended option for many invasive fungal infections, with lipid formulations preferred where renal toxicity is a concern.

Reference: IDSA Invasive Candidiasis Guidelines (2016); ESCMID Cryptococcal Meningitis Guidelines (2018); NICE TA350 (AmBisome); BSAC antifungal guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Drugs

Nystatin · Polyene antifungal

Pathways