This page covers safety at standard therapeutic doses for FDA-approved indications. All safety decisions should be made in consultation with a licensed pharmacist or physician.
Contraindications (Do Not Take If…)
- ✗You are pregnant or may be pregnant. Ivermectin is teratogenic in animal studies at therapeutic doses.
- ✗You have a known hypersensitivity to ivermectin or any component of the formulation.
- ✗You are taking warfarin (Coumadin). Ivermectin can significantly increase INR. Use requires close monitoring.
- ✗You have heavy Loa loa infection (loiasis). Risk of serious encephalopathy.
- ✗You have a condition affecting the blood-brain barrier (e.g., bacterial meningitis). Ivermectin CNS penetration risk increases.
Common Side Effects
At therapeutic doses for approved indications, ivermectin is generally well-tolerated. Common side effects include:
- Dizziness or lightheadedness
- Nausea or stomach upset
- Diarrhea
- Pruritus (itching), skin rash
- Headache
- The Mazzotti reaction (when treating onchocerciasis) — fever, rash, tachycardia caused by dying parasites, not the drug
Key Drug Interactions
| Drug | Interaction |
|---|---|
| Warfarin (Coumadin) | Ivermectin significantly potentiates warfarin anticoagulation. INR must be monitored closely. |
| Certain antiretrovirals | Some HIV medications (ritonavir-boosted regimens) may increase ivermectin levels via CYP3A4 inhibition. |
| Alcohol | Avoid — may potentiate CNS effects. |
| Barbiturates, benzodiazepines | May increase CNS depression when combined with ivermectin. |
Discuss all current medications with your pharmacist or physician before taking ivermectin.