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Pharmacology · Antitrypanosomals

Pentamidine !

Parenteral diamidine for Pneumocystis pneumonia, leishmaniasis and early sleeping sickness; it can cause severe hypotension and hypoglycaemia.

Updated 2026-11-01

  • Class: Antitrypanosomals
  • Target: Several parasite targets (DNA, RNA, phospholipid and protein synthesis)
  • ATC code: P01CX01
  • WHO Model List of Essential Medicines

Also called: Pentamidine isethionate

Mechanism of action

A positively charged aromatic diamidine whose exact mechanism is unknown. It enters the parasite through several transporters (in T. brucei mainly an aquaglyceroporin) and disrupts nuclear metabolism, inhibiting DNA, RNA, phospholipid and protein synthesis. Loss of that transporter explains cross-resistance with melarsoprol.

  1. Enters the parasite through membrane transporters
  2. Accumulates because of its positive charge
  3. Inhibits DNA, RNA, phospholipid and protein synthesis
  4. The protozoan or the fungus Pneumocystis dies

Pharmacokinetics

Absorption
Barely absorbed orally: given IM or IV
Distribution
Very wide; concentrates in liver, kidney and lung; does not cross the blood-brain barrier
Elimination
Mostly unchanged in urine, for weeks after stopping
Half-life
Very long terminal half-life, days to weeks

Indications

  • Pneumocystis jirovecii pneumonia, as an alternative Pneumocystis pneumonia (PCP) →
  • Cutaneous leishmaniasis, as second line; also second-line for visceral leishmaniasis Leishmaniasis →
  • Early-stage African sleeping sickness due to T. b. gambiense (mainly in young children)

Adverse effects

Common

  • Impaired kidney function and raised creatinine, very common
  • Sterile abscesses, necrosis and pain at the IM injection site
  • Leucopenia and thrombocytopenia
  • Raised liver enzymes
  • Nausea, loss of appetite and bad taste
  • Rash

Contraindications

  • Electrocardiogram abnormalities (in leishmaniasis, per the Colombian guidance)
  • Pregnancy (not recommended in leishmaniasis)
  • Hypersensitivity to pentamidine

Key interactions

Aminoglycosides, amphotericin B, cisplatin, foscarnet or vancomycin
Additive nephrotoxicity; avoided or closely monitored
Fluconazole or foscarnet in the same line
Incompatible in solution

What is monitored

  • Blood pressure during and after each dose
  • Daily blood glucose
  • Daily creatinine and urea
  • Blood count with platelets, liver tests and calcium
  • Electrocardiogram

Administration and safety

  • IV as a slow infusion (rapid infusion causes hypotension) or deep IM; many prefer IV because of abscesses.
  • Not reconstituted with sodium chloride because it precipitates.
  • The patient lies down during the infusion, with resuscitation equipment at hand.
  • If extravasation occurs, stop at once and restart in another vein.

Nursing care

  • Before and during: patient lying down, frequent blood pressure until stable.
  • Check glucose: watch for sweating, tremor and confusion (hypoglycaemia) and, weeks or months later, thirst and heavy urination (diabetes).
  • Watch creatinine and urine output; report severe abdominal pain (pancreatitis).
  • Check the infusion or injection site for extravasation, necrosis or abscesses.

Pregnancy and breastfeeding

There are no animal reproduction studies; for leishmaniasis the Colombian guidance does not recommend it in pregnancy.

Test yourself

Think of the answer, then tap the question to see it.

Which glucose disturbance does pentamidine cause first, and which can follow?

First hypoglycaemia from islet cell damage; later, hyperglycaemia or diabetes.

Why must the patient lie down during IV pentamidine?

Because it can cause severe hypotension, especially with rapid infusion.

Why does pentamidine not work in late-stage sleeping sickness?

Because it does not cross the blood-brain barrier.

Which solution is pentamidine not reconstituted with?

Sodium chloride, because it precipitates.

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: DailyMed - PENTAMIDINE ISETHIONATE injection, powder, lyophilized, for solution (DailyMed (U.S. National Library of Medicine), 2026); Lineamientos de atención clínica integral para Leishmaniasis en Colombia (Ministerio de Salud y Protección Social (Colombia), 2023); Clinical Care of Leishmaniasis (Centers for Disease Control and Prevention (CDC), 2024); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 67 (McGraw Hill, 2023).

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