Pentamidine
**Pentamidine** is an antiprotozoal agent primarily used in veterinary medicine as a second-line or salvage treatment for **leishmaniosis** in dogs, particularly when resistance to pentavalent antimony drugs (e.g., meglumine antimonate and sodium stibogluconate) has occurred. > **Warning:** Pentamidine is a highly toxic drug with a narrow therapeutic index. The potential to cause severe toxic damage, particularly to the kidneys and liver, must be carefully weighed against the benefits. **Clinical Pearl:** Due to its significant toxicity profile and the availability of safer alternatives (like allopurinol and miltefosine), pentamidine is rarely used as a first-line agent. Expert advice should always be sought prior to initiating therapy.
Mechanism: Pentamidine kills protozoans by interacting with **parasite DNA**. It is rapidly taken up by the parasites via a **high-affinity energy-dependent carrier** → disrupts DNA, RNA, and protein synthesis → leads to protozoal death.
Dosing by species
- Leishmaniosis (resistant cases) · 4 mg/kg · IM · q48-72h · Seek expert advice on treatment duration · Use only when resistance to pentavalent antimony drugs has occurred. Highly toxic.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Impaired liver function
- Impaired kidney function
- Rapid intravenous (IV) injection (due to severe cardiovascular effects)
Adverse effects
- Pain at the injection site
- Necrosis at the injection site
- Hypotension
- Nausea
- Salivation
- Vomiting
- Diarrhoea
- Hypoglycaemia
- Blood dyscrasias
Drug interactions
- Nephrotoxic drugs (e.g., Aminoglycosides, NSAIDs) · Increased risk of severe nephrotoxicity · major
Monitoring
- Renal function (BUN, Creatinine, Urinalysis)
- Liver enzymes (ALT, AST, ALP) and Bilirubin
- Blood glucose concentrations
- Blood pressure (especially around the time of administration)
- Complete Blood Count (CBC) for dyscrasias
- Injection site for signs of necrosis
Overdose
Overdosage significantly increases the risk of severe **hypotension**, **hypoglycaemia**, **acute renal failure**, and **hepatotoxicity**. Treatment is largely supportive and symptomatic, including IV fluid therapy to support blood pressure and renal perfusion, and dextrose supplementation for hypoglycaemia.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.