Amphotericin B
Indications
Amphotericin B is a powerful antifungal medicine used in hospital to treat serious, life-threatening fungal infections, such as invasive candidiasis, aspergillosis, cryptococcal meningitis, mucormycosis (black fungus), histoplasmosis and other deep fungal infections. It is also used to treat visceral leishmaniasis (kala-azar), a parasitic disease found in Bangladesh, and sometimes as empirical treatment in patients with low white cell counts and persistent fever. It is given by injection by a doctor or nurse.
How It Works
Amphotericin B binds to ergosterol, a building block of the fungal cell membrane. This creates holes in the membrane so the contents of the cell leak out and the fungus dies. Lipid-based forms (liposomal and lipid complex) deliver the medicine in fatty particles, which reduces kidney damage and infusion reactions.
Dosage and Administration
Amphotericin B is given only as a slow intravenous infusion in hospital, by a doctor or nurse. The dose and length of treatment are set by the doctor based on the type of infection, the formulation (conventional or lipid-based), body weight and kidney function. Conventional and lipid-based forms have very different doses and are not interchangeable. A test dose and pre-medication may be used to reduce infusion reactions.
Interactions
- Other medicines that can harm the kidneys, such as Aminoglycosides (Gentamicin, Amikacin), Ciclosporin, Tacrolimus, Vancomycin and some anticancer drugs: higher risk of kidney damage.
- Corticosteroids and diuretics: higher risk of low potassium.
- Digoxin: low potassium increases the risk of digoxin toxicity.
- Flucytosine: Amphotericin B may increase its toxicity; monitoring is needed.
- Muscle relaxants used in anaesthesia: low potassium may increase their effect.
Contraindications
- Known severe allergy to Amphotericin B or any ingredient, unless the doctor decides the infection is life-threatening and no alternative exists.
Side Effects
During or soon after the infusion, fever, chills, shaking, headache, nausea, vomiting and low blood pressure are common, especially with the conventional form. Other common effects include kidney impairment, low potassium and magnesium, anaemia, and pain or inflammation at the drip site. Lipid-based forms cause these effects less often. Rarely, serious allergic reactions, heart rhythm problems or liver changes occur.
Tell the nurse or doctor immediately if you have difficulty breathing, chest pain, swelling of the face or throat, severe shaking or fever during the infusion, palpitations, muscle weakness or cramps, or a big drop in urine output.
Pregnancy and Lactation
Amphotericin B is used in pregnancy when the infection is serious and the benefit outweighs the risk, as decided by the doctor. It is not known whether it passes into breast milk; the doctor will advise about breastfeeding.
Precautions and Warnings
- Kidney function, potassium, magnesium, blood counts and liver tests are checked regularly during treatment.
- Fluids and salt are often given before each dose to protect the kidneys.
- Check the product name and dose carefully: errors between conventional and lipid forms can be fatal.
- Used only under close medical supervision in hospital.
Overdose
Overdose, especially with the conventional form, can cause heart and breathing arrest. It is managed in hospital by stopping the infusion and giving supportive care.
Therapeutic Class
Polyene antifungal (also anti-leishmanial).
Storage
Hospital medicine: store as directed on the pack, usually in a refrigerator at 2 to 8°C, protected from light; do not freeze. Some lipid forms are stored below 25°C. Keep out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.
All brands of Amphotericin B