Isometamidium Chloride
Dosage & Administration Guidelines
| Species | Route | Dose | Frequency | Duration & Clinical Notes |
|---|---|---|---|---|
| Cattle | IM (deep intramuscular) | 1 mg/kg for treatment; 0.5-1 mg/kg for prophylaxis | Single dose; may be repeated after 3-6 months for prophylaxis | Duration: Single administration Notes: For prophylaxis, a dose of 0.5-1 mg/kg provides protection for up to 3-4 months. For treatment, a single dose of 1 mg/kg is typical. Do not exceed 1 mg/kg to minimize local reactions. |
| Sheep and Goats | IM (deep intramuscular) | 1 mg/kg | Single dose | Duration: Single administration Notes: Use with caution in small ruminants; monitor for local reactions. |
Clinical Indications & Species Uses
- Treatment and prophylaxis of trypanosomiasis in livestock, particularly in sub-Saharan Africa.
- Treatment and prophylaxis of bovine trypanosomiasis caused by Trypanosoma congolense, T. vivax, and T. brucei.
- Treatment and prophylaxis of trypanosomiasis in sheep and goats.
Pharmacology & Mechanism of Action
Drug Class: Antiprotozoal | Pharmacological Group: Diamidine derivative
Mechanism of Action: Isometamidium chloride is a diamidine compound that exerts its trypanocidal effect by binding to the minor groove of DNA in trypanosomes, thereby inhibiting nucleic acid synthesis and disrupting kinetoplast DNA replication. It also interferes with mitochondrial function and energy metabolism, leading to parasite death. The drug is primarily effective against extracellular trypanosomes in the blood and tissues.
Pharmacodynamics: Isometamidium chloride is a potent trypanocide with both prophylactic and therapeutic activity. It is effective against Trypanosoma congolense, T. vivax, and T. brucei species. The drug has a prolonged residual effect, providing protection against re-infection for several weeks to months depending on the species and dose. Its activity is dose-dependent, with higher doses providing longer prophylaxis but increased risk of local reactions.
β‘ Pharmacokinetics Summary
Available Formulations & Strengths
Contraindications & Clinical Warnings
- Known hypersensitivity to isometamidium chloride or other diamidines.
- Do not use in animals with severe hepatic or renal impairment.
- Do not use in lactating animals if milk is intended for human consumption (unless withdrawal times are observed).
- Do not use in animals with concurrent infections that may exacerbate toxicity.
- Administer by deep intramuscular injection only; subcutaneous or intravenous administration may cause severe tissue damage or systemic toxicity.
- Use with caution in debilitated or stressed animals.
- Avoid repeated injections at the same site to minimize local tissue damage.
- In cattle, local reactions at the injection site are common and may include swelling and pain.
- Do not use in animals intended for breeding within a short period after treatment, as the drug may affect fertility.
- Wear protective clothing and gloves when handling the drug; avoid self-injection.
- Keep out of reach of children and unauthorized personnel.
Adverse Effects & Reactions
Common:
- Local swelling and pain at injection site
- Transient salivation
- Mild gastrointestinal disturbances (e.g., diarrhea)
- Injection site abscess (if not administered properly)
Serious / Severe:
- Severe local tissue necrosis
- Anaphylactic reactions (rare but possible)
- Hepatotoxicity and nephrotoxicity with overdose
- Cardiotoxicity (arrhythmias) with high doses
Rare:
- Neurological signs (e.g., ataxia, tremors)
- Blood dyscrasias (e.g., leukopenia)
- Abortion in pregnant animals
Key Drug Interactions
| Interacting Drug / Class | Clinical Effect & Mechanism | Severity |
|---|---|---|
| Other trypanocidal drugs (e.g., diminazene aceturate) | Potential additive toxicity; avoid concurrent use or use with caution. | Moderate |
| Organophosphate insecticides | May increase toxicity; avoid concurrent use. | High |
| Neuromuscular blocking agents | Potential enhanced neuromuscular blockade; use with caution. | Moderate |
Overdose & Toxicity Management
Signs of Toxicity:
- Severe local tissue necrosis
- Hepatic and renal failure
- Cardiac arrhythmias
- Neurological signs (e.g., convulsions, paralysis)
- Death
Emergency Treatment Protocol: There is no specific antidote. Treatment is symptomatic and supportive. Induce emesis if oral ingestion occurs (not applicable for injectable). Provide intravenous fluids to maintain hydration and renal function. Monitor cardiac and hepatic function. Administer anti-inflammatory drugs for local reactions. In severe cases, consider blood transfusion or dialysis if available.
Food Animal Withdrawal Times
Withdrawal period for meat is 30 days. Not approved for use in lactating animals producing milk for human consumption; milk withdrawal is not established, so do not use in dairy animals. No egg withdrawal applicable as not used in poultry.
Storage, Handling & Regulatory Information
Storage Temperature: Store at controlled room temperature (15-30Β°C).
Light Sensitivity: Light-sensitive β protect from direct exposure.
Handling & Special Conditions: Protect from light. Keep container tightly closed. Do not freeze. Store in a cool, dry place away from direct sunlight.
Dispensing Status: Prescription Required (Rx Only)
Approval Status: Not approved by the FDA for veterinary use in the United States. Approved in many African and European countries for use in livestock.
Extra-Label (Off-Label) Use: In the US, isometamidium chloride is not approved for use in food animals; extra-label use is prohibited in food-producing animals. In other countries, it is available for veterinary use under prescription. Follow local regulations and withdrawal times.
Clinical Pearls & Practice Notes
References & Literature
- π Plumb's Veterinary Drug Handbook
- π Papich Veterinary Pharmacology and Therapeutics
- π Compendium of Veterinary Products (CVP)