1. Introduction
Ivermectin is an antiparasitic medication widely used to treat a variety of parasitic infections in humans. It works by binding to specific ion channels in parasites, causing paralysis and death. Ivermectin is effective against several nematodes, ectoparasites, and some off-label viral infections.
2. Indications
- Approved Indications:
- Onchocerciasis (river blindness).
- Strongyloidiasis.
- Scabies (moderate to severe or crusted).
- Pediculosis (lice infestation).
- Other filarial infections (e.g., lymphatic filariasis as part of combination therapy).
- Off-Label Uses:
- Rosacea (papulopustular type).
- Demodicosis.
3. Dosage
- Adults:
- Onchocerciasis: 150 mcg/kg orally as a single dose; repeat every 6–12 months as needed.
- Strongyloidiasis: 200 mcg/kg orally once daily for 1–2 days.
- Scabies: 200 mcg/kg orally as a single dose; repeat in 7–14 days if needed.
- Pediculosis: 200 mcg/kg orally as a single dose; repeat in 7 days if needed.
- Children (>15 kg):
- Same dosing as adults, adjusted for weight.
- Elderly:
- Use the same dosing as adults; monitor for adverse effects.
4. Administration
- Take orally on an empty stomach with water for optimal absorption.
- Topical formulations (e.g., for rosacea) should be applied to the skin once daily to the affected areas.
5. Forms Available
- Tablets: 3 mg, 6 mg, 12 mg.
- Cream: 1% ivermectin for topical use.
6. Side Effects
6.1. Common Side Effects
- Dizziness.
- Nausea.
- Fatigue.
- Abdominal pain.
6.2. Less Common Side Effects
- Rash.
- Itching (pruritus).
- Diarrhoea.
6.3. Rare but Serious Side Effects
- Hypersensitivity reactions.
- Neurological effects (e.g., confusion, seizures).
- Mazzotti reaction (fever, rash, and systemic symptoms due to rapid parasite death).
7. Warnings
- Neurological Disorders: Use cautiously in patients with conditions affecting the blood-brain barrier, as ivermectin may have increased CNS penetration.
- Severe Parasitic Load: Patients with a heavy parasitic burden (e.g., onchocerciasis) may develop an intense inflammatory response (Mazzotti reaction).
8. Precautions
- Avoid in children under 15 kg or younger than 5 years unless prescribed by a specialist.
- Use cautiously in elderly patients and those with liver impairment.
- Ensure hydration to reduce side effects like dizziness.
9. Interactions
- Drug-Drug Interactions:
- Warfarin: May increase anticoagulant effect; monitor INR closely.
- Benzodiazepines: Increased risk of CNS depression.
- CYP3A4 inhibitors (e.g., ketoconazole): May increase ivermectin plasma levels.
- Drug-Food Interactions:
- Take on an empty stomach to enhance absorption.
10. Monitoring Parameters
- Symptom resolution (e.g., relief from itching, elimination of parasites).
- Liver function tests in prolonged therapy.
- Signs of allergic or inflammatory reactions during treatment.
11. Use in Children
- Safe for use in children >15 kg. Avoid in children weighing <15 kg due to insufficient safety data.
12. Use in Pregnancy
- Category C: Use only if the potential benefits outweigh the risks. Avoid use in the first trimester.
13. Use in Elderly
- Safe with standard dosing, but monitor for side effects, particularly CNS-related symptoms.
14. Use in Kidney Disease
- No dose adjustment required, but caution is advised in severe renal impairment due to limited data.
15. Use in Liver Disease
- Use cautiously in hepatic impairment as ivermectin is metabolised in the liver.
16. Patient Counselling Points
- Take ivermectin on an empty stomach with a full glass of water for best absorption.
- Report any severe symptoms, such as fever, rash, or confusion, to your doctor immediately.
- Follow up with your healthcare provider if symptoms do not improve or worsen after treatment.
- For scabies or lice, ensure proper environmental decontamination (e.g., washing bedding, clothes).
- Adhere to prescribed dosing intervals for complete parasite elimination.
17. Table of Brand Names, Manufacturers, and Prices
Brand Name | Manufacturer | Price (USD) |
---|---|---|
Stromectol | Merck & Co. | $30–50 (4 tablets, 3 mg each) |
Soolantra (cream) | Galderma | $150–200 (30 g, 1%) |
Generic Ivermectin | Various manufacturers | $10–20 (10 tablets, 3 mg each) |
18. FAQs (15 Questions)
- What is ivermectin used for?
Ivermectin is used to treat parasitic infections such as scabies, lice, onchocerciasis, and strongyloidiasis. - How does ivermectin work?
It binds to parasite-specific ion channels, causing paralysis and death of the parasite. - How long does ivermectin take to work?
Symptom relief begins within 1–2 days, but full treatment may require repeated doses depending on the condition. - Can ivermectin cause side effects?
Yes, common side effects include dizziness, nausea, and fatigue. - Is ivermectin safe during pregnancy?
Use during pregnancy is not recommended unless the potential benefit outweighs the risk. Avoid during the first trimester. - Can ivermectin be used for children?
Yes, it is safe for children weighing >15 kg. It is not recommended for children under 15 kg. - What is the recommended dose of ivermectin for scabies?
A single dose of 200 mcg/kg, repeated after 7–14 days if needed. - Can ivermectin be taken with food?
It is best taken on an empty stomach for optimal absorption. - Can ivermectin treat viral infections?
Ivermectin is not officially approved for treating viral infections. Consult your doctor for appropriate use. - What is a Mazzotti reaction?
It is an inflammatory response to rapid parasite death, presenting with fever, rash, and swollen lymph nodes. - How should ivermectin cream be used?
Apply a thin layer of ivermectin cream once daily to the affected skin, avoiding the eyes and mouth. - Can I take ivermectin with other medications?
Consult your doctor, as ivermectin interacts with medications like warfarin and CYP3A4 inhibitors. - How should ivermectin be stored?
Store at room temperature, away from moisture and heat. - What should I do if I miss a dose of ivermectin?
Take it as soon as you remember, but skip it if it’s close to the next dose. Do not double up. - Is ivermectin available over the counter?
In most countries, ivermectin requires a prescription. Always consult your doctor before use.