Ivermectin Dosing for a 65 kg Patient
For a 65 kg patient, the appropriate ivermectin dose is 13 mg (200 mcg/kg × 65 kg = 13,000 mcg or 13 mg), which equals 6.5 tablets of standard 2 mg ivermectin tablets.
Dosage Calculation
The recommended dosage of ivermectin for most parasitic conditions is 200 mcg/kg (micrograms per kilogram) as indicated in the guidelines 1. For a patient weighing 65 kg:
- Calculation: 200 mcg/kg × 65 kg = 13,000 mcg = 13 mg
- With standard 2 mg tablets: 13 mg ÷ 2 mg = 6.5 tablets
Administration Guidelines
- Ivermectin should be taken as a single oral dose with food to increase bioavailability 1
- For certain conditions like scabies, a second dose is recommended after 2 weeks 1
- The medication should be taken with water on an empty stomach
Specific Conditions and Dosing Considerations
Scabies Treatment
- Standard dose: 200 mcg/kg as a single dose 1
- A second dose should be administered 2 weeks after the first dose due to ivermectin's limited ovicidal activity 1
- For crusted (Norwegian) scabies: Higher and more frequent dosing may be required - 200 mcg/kg on days 1,2,8,9, and 15 1
Onchocerciasis
- Standard dose: 200 mcg/kg as a single dose 1
- Some research suggests higher doses (300 mcg/kg) may be more effective 2
Strongyloidiasis
- Standard dose: 200 mcg/kg as a single dose 1
- For immunocompromised patients: 200 mcg/kg on days 1,2,15, and 16 1
Safety Considerations
Pregnancy: Ivermectin is classified as "human data suggest low risk" in pregnancy and probably compatible with breastfeeding 1
Hepatic impairment: The safety of multiple doses in patients with severe liver disease is not known 1
Renal impairment: No dosage adjustments are required for patients with renal impairment 1
Drug interactions: Metabolism may be induced by anticonvulsants and steroids 1
Administration timing: Take with food to increase bioavailability 1
Potential Adverse Effects
- Common: Dizziness, nausea, fever, headache, muscle/joint pain 1
- In onchocerciasis: Mazzotti reaction (fever, urticaria, tender lymphadenopathy, headache) 1
- Rare: Abdominal pain, diarrhea, rash 1
Monitoring
- For scabies: Evaluate after 2 weeks if symptoms persist 1
- For crusted scabies: Close monitoring is required with potential for additional doses 1
- Monitor for adverse reactions, particularly in elderly or debilitated patients 1
Ivermectin has a wide therapeutic index, and studies have shown doses up to 2000 mcg/kg (10 times the standard dose) are well-tolerated 3, but the standard 200 mcg/kg dose is recommended for most indications to balance efficacy and safety.