Ivermectin Dosage Calculator
Calculate Your Ivermectin Dose
This tool calculates the correct oral ivermectin dosage based on your weight and condition.
Your calculated dose will appear here.
Key Takeaways
- Ivermectin is an oral antiparasitic that can clear many skin‑dwelling parasites when topical options fall short.
- Common indications include scabies, demodicosis, cutaneous larva migrans, and onchocerciasis‑related eye skin disease.
- Standard adult dose for most skin parasites is 200µg/kg single dose; severe cases often need a repeat dose after 7‑10days.
- Side‑effects are usually mild-headache, nausea, transient rash-but contraindications exist for pregnant women and patients on certain anticoagulants.
- Compared with permethrin 5% cream, ivermectin offers easier dosing for widespread infestations and better compliance.
When tiny creatures take refuge in your skin, the itch can become unbearable. While the market is full of creams and lotions, there’s a single‑tablet hero that doctors turn to for stubborn cases: Ivermectin is a broad‑spectrum antiparasitic medication originally derived from the soil bacterium Streptomyces avermitilis. It works by binding to glutamate‑gated chloride channels in parasites, causing paralysis and death. Over the past two decades, ivermectin has proven effective not just for internal worms but also for a handful of skin‑dwelling parasites that cause intense itching and rash.
One of the most familiar parasites is Scabies (Sarcoptes scabiei), a microscopic mite that burrows under the epidermis. Classic scabies spreads through close skin‑to‑skin contact, leading to a red, papular rash that’s worst at night. In severe outbreaks-known as crusted or Norwegian scabies-the mite load can reach millions, making topical creams alone insufficient. Ivermectin steps in as an oral rescue, reaching every mite in the body with a single dose.
Parasite‑Related Skin Conditions You Might Encounter
Before deciding on a treatment plan, it helps to know which parasites are likely behind the lesions. Here are the most common culprits:
- Scabies (Sarcoptes scabiei): Itchy burrows, especially between fingers, wrists, and waistline.
- Demodicosis: Overgrowth of the already‑present Demodex folliculorum mite, often linked to rosacea‑like redness around the nose and cheeks.
- Cutaneous larva migrans: Hookworm larvae (Ancylostoma braziliense) that crawl just under the skin, creating serpentine tracks.
- Onchocerciasis (river blindness): Caused by Onchocerca volvulus; skin manifestations include intense itching, depigmented “leopard‑skin” patches, and nodules.
- Myiasis: Fly larvae that infest wounds or intact skin, leading to painful boil‑like lesions.
Each of these conditions has a distinct clinical picture, but they all share the common denominator of an unwanted parasite living on or in the skin. Recognizing the pattern early speeds up treatment and reduces the risk of spreading to family members or community contacts.
How Ivermectin Attacks Skin Parasites
Ivermectin’s magic lies in its ability to cross the skin’s barrier after oral ingestion and reach the parasite’s nervous system. The drug binds selectively to glutamate‑gated chloride channels that are abundant in invertebrates but virtually absent in mammals. When the channel opens, chloride floods the cell, hyperpolarising the membrane and paralyzing the parasite. A paralyzed mite or larva can no longer feed, migrate, or reproduce, and it eventually dies.
Because ivermectin is lipophilic, it distributes well into fatty tissues, including the dermis. This property makes it especially useful for parasites that hide deep in skin layers, like the burrowing scabies mite or the subepidermal larvae of cutaneous larva migrans.
When to Choose Ivermectin: Indications & Diagnosis
Oral ivermectin isn’t the first‑line therapy for every skin parasite, but clinicians consider it when:
- Topical agents (permethrin 5%, benzyl benzoate, sulfur ointment) have failed or are impractical.
- The infestation is extensive-covering large body surface areas-or is crusted, making cream application difficult.
- Patients have contraindications to topical agents, such as severe dermatitis or allergy.
- There is a need for rapid community‑wide control, as oral dosing ensures compliance.
Diagnosis usually starts with a thorough history (recent travel, contact with infested individuals, animal exposure) and a focused skin exam. In doubtful cases, a skin scrapings or skin‑surface biopsy can confirm the presence of mites or larvae under microscopy.
Dosage Guidelines for Different Conditions
Below is a practical dosage chart for the most common parasitic skin diseases. Doses are expressed per kilogram of body weight; tablets typically come in 3mg or 6mg strengths.
| Condition | Standard Adult Dose | Repeat Dose | Special Notes |
|---|---|---|---|
| Scabies (classic) | 200µg/kg PO, single dose | Repeat after 7days if itching persists | Treat close contacts simultaneously |
| Crusted scabies | 200µg/kg PO on Day1,2,8,9,15 | None | Combine with topical permethrin 5% |
| Demodicosis | 200µg/kg PO, single dose | Repeat after 7days, then weekly for 4weeks | Adjunctive topical metronidazole often used |
| Cutaneous larva migrans | 200µg/kg PO, single dose | Second dose after 5‑7days if lesions continue migrating | Consider albendazole if lesions are extensive |
| Onchocerciasis (skin manifestations) | 150µg/kg PO, once every 6months | None | Annual mass‑drug administration programs use this schedule |
For children under 15kg, dosing must be carefully calculated, and safety data below that weight are limited. Always round to the nearest whole tablet and avoid splitting tablets when possible.
Safety, Side Effects, and Contraindications
Ivermectin enjoys a solid safety record, especially when used at the recommended dose. Commonly reported mild adverse events include:
- Transient headache
- Nausea or mild stomach upset
- Low‑grade fever
- Temporary skin rash-often a sign of the parasite’s death (Mazzotti reaction)
Serious reactions are rare but can occur, especially in patients with high microfilarial loads (e.g., in onchocerciasis). The so‑called Mazzotti reaction may present as intense itching, swelling, and fever. Pre‑treating with antihistamines or a short course of corticosteroids can blunt this response.
Contraindications and cautions include:
- Pregnancy: animal studies suggest teratogenic risk; avoid unless benefits outweigh risks.
- Breast‑feeding: minimal data; best to defer.
- Severe hepatic impairment: reduced metabolism may raise plasma levels.
- Concurrent use of strong CYP3A4 inhibitors (e.g., ketoconazole) - may increase ivermectin exposure.
Patients on anticoagulants such as warfarin should be monitored, as ivermectin can mildly affect platelet function.
Comparing Ivermectin with Other Treatments
While ivermectin shines in many scenarios, clinicians often weigh it against topical agents. The table below highlights the main differences.
| Aspect | Ivermectin (oral) | Permethrin 5% (topical) |
|---|---|---|
| Administration | Single tablet (or repeat dose) | Apply cream overnight, repeat after 1week |
| Coverage | Systemic - reaches all body sites, including scalp and nails | Surface only - difficult on thick skin or crusted lesions |
| Compliance | High - one‑time action | Variable - requires proper application over large areas |
| Side‑effects | Mild systemic symptoms | Skin irritation, burning, rarely allergic dermatitis |
| Cost (UK, 2025) | ~£12 per tablet | ~£8 per 30g tube |
In practice, many clinicians prescribe both: a dose of ivermectin for systemic clearance and a single application of permethrin to mop up any residual mites on the skin surface.
Practical Tips for Patients Starting Ivermectin
- Take with food. A fatty meal improves absorption.
- Set a reminder for the repeat dose (if needed) on day7‑10.
- Wash all bedding, clothing, and towels in hot water (≥60°C) and dry on high heat.
- Notify close contacts-family, roommates, or sexual partners-so they can be treated simultaneously.
- Monitor for a mild rash a few days after the dose; it often means the parasites are dying.
- Contact a healthcare professional if you develop high fever, severe headache, or persistent vomiting.
Following these steps reduces the chance of reinfestation and speeds up recovery. Most people feel relief within 3‑5days, although the itching may linger for up to two weeks as the skin heals.
Frequently Asked Questions
Can I use ivermectin for a single itchy spot?
If the spot is due to a confirmed parasite like scabies, a single oral dose often clears it. However, many itchy patches are caused by allergies or eczema, so a proper diagnosis is essential before taking medication.
Is ivermectin safe for children?
Children weighing more than 15kg can safely receive the standard 200µg/kg dose. Below that weight, doctors usually prefer topical treatments because safety data are limited.
Do I need to avoid alcohol while taking ivermectin?
Moderate alcohol consumption does not significantly affect ivermectin’s effectiveness, but excessive drinking can worsen nausea-a common mild side‑effect.
How long does it take for my skin to look normal again?
The parasites die within 24‑48hours, but inflammation can linger. Most patients see noticeable improvement in 3‑5days, with full skin recovery in 2‑3weeks.
Can ivermectin treat fungal skin infections?
No. Ivermectin targets parasites, not fungi. For fungal infections, antifungal creams or oral terbinafine are the right choices.
If you suspect a parasitic skin condition, consult a healthcare professional for confirmation and a personalized treatment plan. Remember, the right medication-paired with good hygiene-will have the itch gone faster than you think.
NORMAND TRUDEL-HACHÉ
October 15, 2025 AT 22:55Ivermectin has become the darling of every "quick-fix" blogger, but the reality is far less glamorous. Oral antiparasitics sound convenient until you consider the cost and the need for proper dosing. For most mild scabies cases, a simple permethrin cream does the job without a prescription. So before you pop a tablet, weigh the evidence and ask a real clinician.
AJIT SHARMA
October 17, 2025 AT 02:42How can we, in this great nation, ignore the ancient wisdom of topical treatments? The Western obsession with pills is a tragedy of our times, and it blinds us to simpler, natural remedies.
Thomas Ruzzano
October 18, 2025 AT 06:29Look, the data on ivermectin for skin parasites is solid, but the hype machine makes it sound like a miracle cure. A single dose can indeed clear scabies, yet you still need to treat contacts and follow hygiene protocols. If you skip the repeat dose, you risk a resurgence. And don't forget the rare, but nasty Mazzotti reaction-people love drama, but the side‑effects can be real. Bottom line: it's a tool, not a silver bullet.
Dan Tenaguillo Gil
October 19, 2025 AT 10:15When dealing with dermatological infestations such as scabies or demodicosis, a comprehensive approach is essential. First, confirm the diagnosis with a skin scraping; visual inspection alone can be misleading. Once the presence of mites or larvae is established, calculate the exact dose based on weight-200 µg per kilogram for most adult patients. Administer the tablet with a fatty meal, as this significantly improves bioavailability. After the initial dose, set a reminder for a repeat dose in seven to ten days, especially for crusted scabies where the mite burden is high. Simultaneously, all close contacts should receive prophylactic treatment to prevent re‑infestation; otherwise, you will be fighting a losing battle. In addition to oral therapy, apply a topical agent such as permethrin to the skin surface; this combination maximizes mite eradication. Clean bedding, clothing, and towels in hot water (at least 60 °C) and tumble‑dry on high heat; parasites survive only briefly outside the human host. Advise patients to avoid scratching to reduce secondary bacterial infection. Monitor for mild side effects-headache, nausea, or a transient rash-and reassure them that these often signify parasite death. If a severe Mazzotti reaction occurs, consider pre‑emptive antihistamines or a short corticosteroid course. For pediatric patients above 15 kg, the same dosing applies, but for younger children, exercise caution and prefer topical modalities. Patients with hepatic impairment may require dose adjustment because ivermectin is metabolized hepatically. Finally, schedule a follow‑up visit within two weeks to assess treatment efficacy and address any lingering symptoms. By integrating oral ivermectin, topical therapy, environmental decontamination, and patient education, you achieve the highest likelihood of cure and prevent recurrence.
Ellie Chung
October 20, 2025 AT 14:02Wow, never knew ivermectin could double as a skin superhero.
Sophia Simone
October 21, 2025 AT 17:49While the author extols the virtues of oral ivermectin, one must acknowledge that the literature also documents instances of suboptimal outcomes when monotherapy is employed without concurrent topical measures; therefore, the assertion of its standalone superiority warrants cautious scrutiny.
Dean Briggs
October 22, 2025 AT 21:35It strikes me that our collective fascination with pharmaceutical solutions often overshadows the philosophical underpinnings of health. When we speak of parasites dwelling beneath the epidermis, we are, in essence, discussing an intrusion upon the body's natural order. The decision to intervene with ivermectin reflects not only a clinical judgment but also a moral stance on bodily autonomy and communal responsibility. Consider, for a moment, the ripple effect of treating a single individual versus implementing a community-wide prophylactic regimen; the latter embodies a utilitarian ethic. Yet, we must also respect individual variance-some patients may experience adverse reactions that, albeit rare, can be profoundly unsettling. Thus, the balance between efficacy, safety, and ethical considerations becomes a nuanced tapestry. Moreover, the environmental impact of widespread drug distribution is an often‑ignored dimension; excretion of active metabolites can influence ecosystems in unforeseen ways. In the end, the clinician's role transcends mere prescription; it becomes an act of stewardship over both individual and collective health. By integrating scientific rigor with compassionate deliberation, we navigate the complex landscape of parasitic skin disease treatment.
Sadie Speid
October 24, 2025 AT 01:22Great points, Dean! Let’s keep the conversation moving and spread the word-knowledge is power!
Sue Ross
October 25, 2025 AT 05:09I appreciate the thorough breakdown of ivermectin use. It’s helpful to see the practical steps laid out so clearly. Thanks for sharing.
Rohinii Pradhan
October 26, 2025 AT 08:55Although the exposition is comprehensive, the author neglects to address the pharmacokinetic variability observed in patients with comorbid hepatic conditions, which may significantly alter therapeutic outcomes; such omissions could mislead practitioners seeking a definitive protocol.
Anna-Lisa Hagley
October 27, 2025 AT 12:42The analysis presents a balanced view, yet the emphasis on oral therapy feels somewhat overstated.
A Walton Smith
October 28, 2025 AT 16:29Meh.
Theunis Oliphant
October 29, 2025 AT 20:15Behold! The age of a single pill promising salvation for every itch is upon us, and yet we stand at the precipice of complacency, forgetting the humble cream that has served us faithfully through centuries of skin battles.