Ivermectin Dosage for a 196-Pound Patient
The recommended dose of ivermectin for a patient weighing 196 pounds (89 kg) is 18 mg, which is calculated as 200 μg/kg (0.2 mg/kg) based on FDA-approved dosing guidelines. 1
Dosage Calculation
- For a patient weighing 196 pounds (89 kg), the appropriate dose is 200 μg/kg × 89 kg = 17,800 μg or approximately 18 mg 1
- This would equate to 6 tablets of 3 mg ivermectin 1
- The dosage should be taken orally with water 1
Dosing Considerations Based on Indication
- For strongyloidiasis treatment: Single oral dose of 200 μg/kg (18 mg for this patient) 1
- For scabies treatment: 200 μg/kg orally, repeated in 2 weeks 2
- For crusted (Norwegian) scabies: 200 μg/kg on days 1,2,8,9, and 15, with additional doses possibly required on days 22 and 29 for severe cases 2
- For cutaneous larva migrans: Single dose of 200 μg/kg 2
- For onchocerciasis: 150 μg/kg as a single oral dose (approximately 13.5 mg for this patient) 1
Important Administration Guidelines
- Tablets should be taken on an empty stomach with water 1
- For parasitic infections requiring a second dose, the follow-up dose should typically be given 2 weeks after the initial dose 2
- Ivermectin bioavailability is increased when taken with food, which increases penetration into the epidermis - important for skin conditions like scabies 2
Safety Considerations
- Ivermectin is generally well-tolerated at the recommended dosage 3
- No dosage adjustments are required for patients with renal impairment 2
- The safety of multiple doses in patients with severe liver disease is not well established 2
- Ivermectin is classified as "human data suggest low risk" in pregnancy and probably compatible with breastfeeding 2
Common Pitfalls to Avoid
- Avoid using lindane as an alternative, especially in patients with extensive dermatitis, as it can cause toxicity including seizures 2
- Do not administer ivermectin to children weighing less than 15 kg due to potential risk of crossing the blood-brain barrier 2
- Ensure proper weight-based dosing - underdosing may lead to treatment failure 4
- For scabies treatment, remember that symptoms may persist for up to 2 weeks after successful treatment due to allergic reactions to dead mites 2
Treatment Response Considerations
- Follow-up stool examinations should be performed to verify eradication of strongyloidiasis 1
- For scabies, retreatment after 2 weeks should be considered if symptoms persist or live mites are still observed 2
- Higher efficacy is achieved when ivermectin dose exceeds 200 μg/kg and when the delay between doses (if multiple doses are required) is less than 10 days 5
By following these evidence-based dosing guidelines, you can ensure appropriate treatment for this 196-pound patient requiring ivermectin therapy.