Pentamidine Injectable: Dosing and Precautions

Therapeutic action

Antiprotozoal active against Pneumocystis jiroveci (carinii).

Indications

Second-line treatment of pneumocystosis in the event of contra-indication, intolerance, or unresponsiveness to co-trimoxazole.

Forms and strengths, route of administration

Due to the numerous and potentially severe adverse effects of pentamidine, patients should be kept under close surveillance.

• Powder for injection, 200 mg and 300 mg vials, to be dissolved in 10 ml water for injection, for IM injection or infusion in 250 ml of 5% glucose.

Dose and duration

• Child and adult: 4 mg/kg once daily by IM injection or infusion over at least 60 minutes for 14 to 21 days.

Contra-indications, adverse effects, precautions

• Do not administer to patients with severe renal impairment. Reduce dosage in patients with renal impairment.
• May cause aseptic abscess by IM route and venous thrombosis by IV route.
• May cause malaise and hypotension, particularly if administered too rapidly by IV route.
• May also cause gastrointestinal disturbances, renal, hepatic and haematologic disorders, pancreatitis, arrhythmia, torsades de pointes, and hypoglycaemia followed by hyperglycaemia.
• Do not combine with drugs inducing torsades de pointes.
• Avoid combination with mefloquine, cardiac glycosides, azole antifungals, and drugs inducing hypokalaemia.
• Administer on an empty stomach and keep the patient supine during injection and for 30 minutes after.
• Monitor blood pressure, blood glucose, serum creatinine, and blood counts.
• Pregnancy and breast-feeding: contraindicated, except if vital and there is no therapeutic alternative.
• For prophylaxis of pneumocystosis, pentamidine may be used by inhalation of nebulised solution using suitable equipment.
• Pentamidine is also used in the treatment of African trypanosomiasis and leishmaniasis.