Ivermectin Medical Valley: Uses, Dosage & Side Effects

An antiparasitic medicine (anthelmintic) used to treat intestinal strongyloidiasis, lymphatic filariasis, and scabies caused by parasitic organisms

Rx ATC: P02CF01 Antiparasitic
Active Ingredient
Ivermectin
Available Forms
Tablet (3 mg), Cream (10 mg/g)
Known Brands
Soolantra, Scatol
WHO Essential Medicine
Yes

Ivermectin Medical Valley contains the active substance ivermectin, a broad-spectrum antiparasitic agent that belongs to the avermectin class of compounds. Originally derived from the bacterium Streptomyces avermitilis, ivermectin has become one of the most important drugs in tropical medicine since its discovery – an achievement recognized by the 2015 Nobel Prize in Physiology or Medicine. Ivermectin Medical Valley tablets (3 mg) are used to treat intestinal strongyloidiasis, microfilaraemia due to lymphatic filariasis caused by Wuchereria bancrofti, and scabies. Listed on the WHO Model List of Essential Medicines, ivermectin is a cornerstone in the global fight against neglected tropical diseases. It requires a prescription and should only be used when a parasitic infection has been confirmed or is strongly suspected by a doctor.

Quick Facts: Ivermectin Medical Valley

Active Ingredient
Ivermectin
Drug Class
Antiparasitic
ATC Code
P02CF01
Common Uses
Strongyloidiasis, Filariasis, Scabies
Available Forms
Tablet, Cream
Prescription Status
Rx Only

Key Takeaways

  • Ivermectin Medical Valley is an antiparasitic medicine used to treat intestinal strongyloidiasis, lymphatic filariasis caused by Wuchereria bancrofti, and scabies – it does not work against adult worms in filariasis, only immature forms (microfilariae).
  • The tablets are taken as a single dose on an empty stomach, with all prescribed tablets swallowed at the same time with water; food should be avoided for two hours before and after administration.
  • Special caution is required for patients who live in or have travelled to areas of Africa where Loa loa (African eye worm) is endemic, as treatment can cause serious neurological reactions in heavily co-infected individuals.
  • Serious skin reactions including Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported; stop treatment and seek immediate medical attention if you develop painful rash, blistering, or mouth sores.
  • Ivermectin should only be used during pregnancy if clearly necessary; it passes into breast milk, so your doctor may delay treatment until one week after delivery if you are breastfeeding.

What Is Ivermectin Medical Valley and What Is It Used For?

Quick Answer: Ivermectin Medical Valley contains ivermectin, an antiparasitic drug used to treat intestinal strongyloidiasis (roundworm infection), microfilaraemia due to lymphatic filariasis caused by Wuchereria bancrofti, and scabies. It works by paralysing and killing parasites but does not prevent new infections or kill adult worms in filariasis.

Ivermectin Medical Valley contains the active substance ivermectin, which belongs to the avermectin class of compounds – a group of macrocyclic lactones originally isolated from the soil bacterium Streptomyces avermitilis. Ivermectin is one of the most successful antiparasitic drugs ever developed and is listed on the World Health Organization (WHO) Model List of Essential Medicines, reflecting its critical importance in global public health. The discovery of avermectins and their development into therapeutic agents was recognized with the 2015 Nobel Prize in Physiology or Medicine, awarded to William C. Campbell and Satoshi Ōmura.

The mechanism of action of ivermectin is highly selective for invertebrate organisms. It binds with high affinity to glutamate-gated chloride ion channels, which are found in invertebrate nerve and muscle cells but not in mammals. This binding causes an increase in the permeability of the cell membrane to chloride ions, leading to hyperpolarization of the nerve or muscle cell, resulting in paralysis and death of the parasite. Ivermectin also interacts with other ligand-gated chloride channels, including those gated by gamma-aminobutyric acid (GABA). Because glutamate-gated chloride channels are specific to invertebrates, and because ivermectin does not readily cross the blood-brain barrier in mammals, the drug has an excellent safety profile in humans at therapeutic doses.

Ivermectin Medical Valley tablets are approved for the treatment of three distinct parasitic conditions:

  • Intestinal strongyloidiasis: This is an infection of the gastrointestinal tract caused by the nematode (roundworm) Strongyloides stercoralis. The worm has a complex life cycle involving free-living and parasitic stages. Larvae can penetrate the skin (often through the feet), migrate through the lungs, and eventually reach the small intestine where adult worms reside and produce eggs. Strongyloidiasis can be asymptomatic or cause abdominal pain, diarrhoea, and in immunocompromised patients, life-threatening hyperinfection syndrome. Ivermectin is the drug of choice for strongyloidiasis according to WHO and Infectious Diseases Society of America (IDSA) guidelines.
  • Microfilaraemia due to lymphatic filariasis (LF) caused by Wuchereria bancrofti: Lymphatic filariasis is a mosquito-borne disease caused by filarial nematodes. Wuchereria bancrofti is responsible for approximately 90% of cases worldwide. The adult worms live in the lymphatic system and produce millions of microscopic larvae (microfilariae) that circulate in the blood. Over time, the infection can cause lymphoedema and elephantiasis. Ivermectin is effective against the microfilariae (immature forms) but does not kill adult worms, which is why repeated dosing at 6- or 12-month intervals is necessary as part of mass drug administration (MDA) programmes to interrupt transmission.
  • Scabies: Scabies is caused by the mite Sarcoptes scabiei, which burrows into the upper layer of the skin. The mite and its faecal pellets cause an intense allergic itch that is characteristically worse at night. Scabies is highly contagious through direct skin contact and can affect entire households, institutions, and communities. Ivermectin is used orally when topical treatment has failed, is impractical, or for crusted (Norwegian) scabies, a severe form that occurs primarily in immunocompromised individuals. According to WHO guidelines, oral ivermectin may also be used as a first-line treatment in outbreak settings.

It is important to understand that Ivermectin Medical Valley does not prevent parasitic infections – it is a treatment, not a prophylactic measure. It should only be used when a doctor has diagnosed or strongly suspects a parasitic infection. The drug is not effective against adult worms in filariasis, which means that treatment must be repeated over time to control the disease and reduce transmission in endemic areas.

WHO Essential Medicine

Ivermectin is included on the WHO Model List of Essential Medicines for the treatment of onchocerciasis (river blindness), lymphatic filariasis, strongyloidiasis, and scabies. Global mass drug administration programmes using ivermectin have helped protect hundreds of millions of people from parasitic diseases in tropical and subtropical regions, making it one of the most impactful medicines in public health history.

What Should You Know Before Taking Ivermectin Medical Valley?

Quick Answer: Do not take Ivermectin Medical Valley if you are allergic to ivermectin or any of its ingredients, or if you have previously had a serious skin reaction to it. Use special caution if you have a weakened immune system or have lived in or visited areas of Africa where the Loa loa parasite is found. Tell your doctor about all other medicines you are taking.

Contraindications

There are specific situations in which Ivermectin Medical Valley must not be used. Understanding these contraindications is essential to avoid potentially serious adverse reactions.

  • Hypersensitivity: Do not take Ivermectin Medical Valley if you are allergic to ivermectin or any of the other ingredients in the formulation (microcrystalline cellulose, pregelatinised maize starch, citric acid, butylated hydroxyanisole, or magnesium stearate). Signs of an allergic reaction may include skin rash, difficulty breathing, or fever.
  • Previous severe skin reaction: Do not take this medicine if you have ever had a severe skin rash, skin peeling, blistering, and/or mouth sores after taking ivermectin. Serious skin reactions such as Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) have been reported and can be life-threatening.

Warnings and Precautions

Talk to your doctor or pharmacist before taking Ivermectin Medical Valley if any of the following apply to you:

  • Weakened immune system: If you are immunocompromised (for example due to HIV/AIDS, organ transplant medications, or chemotherapy), you may be at higher risk for disseminated strongyloidiasis and may require repeated or prolonged courses of ivermectin under close medical supervision.
  • Travel to or residence in endemic areas of Africa: If you have lived in or travelled to areas where Loa loa is found, you should be tested for this parasite before receiving ivermectin. In patients with high levels of Loa loa microfilariae, ivermectin treatment can trigger a severe inflammatory reaction as the parasites die, potentially causing encephalopathy, coma, or death.
  • Co-infection with Onchocerca volvulus: The use of diethylcarbamazine citrate (DEC) in patients co-infected with Onchocerca volvulus (the parasite causing river blindness) may increase the risk of serious side effects, which can occasionally be severe. Your doctor will consider this when planning your treatment.
  • Serious skin reactions: Stevens-Johnson syndrome and toxic epidermal necrolysis have been reported with ivermectin use. Stop taking ivermectin and seek immediate medical attention if you develop a painful red or purple rash that spreads, blistering of the skin, or sores in the mouth, throat, nose, or genitals. These serious skin reactions may be preceded by fever and flu-like symptoms.

Children

The safety and effectiveness of ivermectin have not been established in children weighing less than 15 kg. For children weighing 15 kg or more who are under 6 years of age, the tablets should be crushed before swallowing to prevent choking. Dosing in children is weight-based and determined by the doctor. There is limited clinical experience with ivermectin in very young children, and its use should be carefully considered against potential benefits.

Pregnancy and Breastfeeding

If you are pregnant or think you may be pregnant, tell your doctor before taking Ivermectin Medical Valley. The drug should only be taken during pregnancy if the potential benefit justifies the potential risk to the unborn child. You and your doctor will make this decision together. Animal reproductive toxicity studies have shown that ivermectin can be teratogenic at high doses, though these doses are substantially higher than the human therapeutic dose.

Ivermectin is excreted in human breast milk. If you are breastfeeding, your doctor may decide to begin treatment one week after your baby’s birth to minimise exposure. If treatment is urgent, discuss the benefits and risks with your doctor. The WHO considers ivermectin compatible with breastfeeding at single therapeutic doses for most indications.

If you are pregnant or breastfeeding, think you may be pregnant, or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine.

Driving and Operating Machinery

Ivermectin may cause dizziness, drowsiness, tremor, or vertigo. If you experience any of these symptoms after taking the medicine, do not drive or operate machinery until the symptoms have resolved. You are responsible for assessing whether you are fit to drive or perform tasks requiring alertness. The effects and side effects of the medicine are described throughout this article – read all sections carefully for guidance.

How Does Ivermectin Medical Valley Interact with Other Drugs?

Quick Answer: Ivermectin is metabolised by CYP3A4 in the liver. Strong CYP3A4 inhibitors may increase ivermectin levels and the risk of toxicity, while CYP3A4 inducers may reduce its effectiveness. Warfarin interactions have been reported, and concurrent use with diethylcarbamazine (DEC) in patients with Onchocerca volvulus infection carries a risk of severe adverse reactions. Always tell your doctor about all medicines you are taking.

Although formal drug interaction studies with ivermectin are limited, clinically significant interactions can occur because ivermectin is primarily metabolised by the cytochrome P450 3A4 (CYP3A4) enzyme in the liver. Medications that affect CYP3A4 activity can alter ivermectin plasma levels, potentially changing its efficacy or toxicity profile. Tell your doctor about all medications, supplements, and herbal products you are currently taking or have recently taken.

Major Interactions

Major Drug Interactions with Ivermectin
Interacting Drug Effect Clinical Significance
Warfarin and other vitamin K antagonists Potential increase in INR (international normalised ratio), increased bleeding risk Monitor INR closely during and after ivermectin treatment; dose adjustment of warfarin may be needed
Diethylcarbamazine (DEC) Increased risk of severe adverse reactions in patients co-infected with Onchocerca volvulus Avoid concurrent use; severe and sometimes life-threatening reactions may occur
Strong CYP3A4 inhibitors (ketoconazole, itraconazole, ritonavir, clarithromycin) Increased ivermectin plasma levels, greater risk of adverse effects Use with caution; monitor for increased side effects
Strong CYP3A4 inducers (rifampicin, carbamazepine, phenytoin, St John’s wort) Decreased ivermectin plasma levels, potentially reduced antiparasitic efficacy Avoid concurrent use if possible; treatment failure may result

Minor Interactions

Other Drug Interactions with Ivermectin
Interacting Drug Effect Clinical Significance
Albendazole (other anthelmintic) Possible additive antiparasitic activity; ivermectin may increase albendazole levels Combination sometimes used intentionally in mass drug administration; monitor for increased side effects
Moderate CYP3A4 inhibitors (erythromycin, diltiazem, grapefruit juice) Possible modest increase in ivermectin levels Use with caution; clinical significance uncertain but monitor for adverse effects
Alcohol May increase the risk of dizziness and drowsiness Avoid alcohol on the day of treatment
P-glycoprotein (P-gp) inhibitors (verapamil, cyclosporine) Potential increase in ivermectin levels by reducing its efflux from cells; theoretical risk of increased CNS penetration Use with caution, especially in patients with compromised blood-brain barrier

The interaction potential of ivermectin is generally considered modest because it is usually administered as a single dose or short course, limiting the duration of any interaction. However, in patients requiring repeated doses (as in lymphatic filariasis programmes) or those taking multiple interacting medications, the cumulative effect should be considered. Your doctor will evaluate your complete medication list and make appropriate recommendations.

What Is the Correct Dosage of Ivermectin Medical Valley?

Quick Answer: Ivermectin is given as a single oral dose, with the number of 3 mg tablets determined by body weight. For strongyloidiasis, the standard dose is approximately 200 µg/kg. For lymphatic filariasis, dosing depends on body weight and whether treatment is given every 6 or 12 months. For scabies, a single dose of 200 µg/kg is given, with a possible repeat dose after 8–15 days. All tablets should be taken at the same time on an empty stomach.

Always take this medicine exactly as your doctor or pharmacist has told you. Check with your doctor or pharmacist if you are not sure. Ivermectin Medical Valley is administered as a single oral dose. All prescribed tablets should be taken at the same time with water on an empty stomach. Do not eat any food within two hours before or after taking the tablets, as food intake may affect how the drug is absorbed by the body.

Intestinal Strongyloidiasis

Strongyloidiasis – Single-Dose Regimen (approximately 200 µg/kg)

Treatment consists of a single dose. Your doctor may recommend repeat treatment if follow-up tests show persistent infection.

Ivermectin Dosing for Intestinal Strongyloidiasis
Body Weight (kg) Dose (number of 3 mg tablets)
15–24 kg 1 tablet
25–35 kg 2 tablets
36–50 kg 3 tablets
51–65 kg 4 tablets
66–79 kg 5 tablets
≥ 80 kg 6 tablets

Lymphatic Filariasis (Wuchereria bancrofti)

Lymphatic Filariasis – Repeated Dosing (every 6 or 12 months)

Indication: Microfilaraemia due to Wuchereria bancrofti

Treatment is repeated every 6 or 12 months as part of a mass drug administration programme or as directed by your doctor. The dose differs depending on the dosing interval.

Ivermectin Dosing for Lymphatic Filariasis (by Body Weight)
Body Weight (kg) Dose every 6 months (3 mg tablets) Dose every 12 months (3 mg tablets)
15–25 kg 1 tablet 2 tablets
26–44 kg 2 tablets 4 tablets
45–64 kg 3 tablets 6 tablets
65–84 kg 4 tablets 8 tablets

If no scale is available, the dose may alternatively be determined by the patient’s height:

Ivermectin Dosing for Lymphatic Filariasis (by Height)
Height (cm) Dose every 6 months (3 mg tablets) Dose every 12 months (3 mg tablets)
90–119 cm 1 tablet 2 tablets
120–140 cm 2 tablets 4 tablets
141–158 cm 3 tablets 6 tablets
> 158 cm 4 tablets 8 tablets

Scabies

Scabies – Single Dose with Possible Repeat

Dose: 200 micrograms per kilogram of body weight, taken as a single dose

Assessment: Wait 4 weeks to evaluate whether treatment has been fully effective

Repeat dose: Your doctor may prescribe a second single dose within 8–15 days of the first

If you feel that the effect of Ivermectin Medical Valley is too strong or too weak, consult your doctor or pharmacist.

Children

Ivermectin Medical Valley is not recommended for children weighing less than 15 kg, as safety and efficacy have not been established in this population. For children weighing 15 kg or more, the dose is calculated based on body weight as described in the tables above. Children under 6 years of age should have the tablets crushed before swallowing. Always follow your doctor’s instructions for dosing in children.

Missed Dose

Since ivermectin is typically given as a single dose, a missed dose situation is uncommon. If you forget to take your dose at the planned time, try to take it as soon as possible according to your doctor’s instructions. Do not take a double dose to make up for a missed dose. Contact your doctor for advice if you are unsure.

Overdose

Administration Instructions

Swallow the tablets whole with water. For children under 6 years, crush the tablets before administration. Take all tablets at the same time on an empty stomach – do not eat within 2 hours before or after taking the medicine, as food may affect absorption.

What Are the Side Effects of Ivermectin Medical Valley?

Quick Answer: Side effects of ivermectin depend on the underlying parasitic infection being treated. They are often related to the body’s inflammatory response to dying parasites rather than direct drug toxicity. For strongyloidiasis: weakness, gastrointestinal symptoms, dizziness. For filariasis: fever, headache, muscle pain. For scabies: temporary worsening of itch. Serious but rare effects include allergic reactions, Stevens-Johnson syndrome, and liver injury. Patients with heavy Loa loa infection may experience severe neurological reactions.

Like all medicines, Ivermectin Medical Valley can cause side effects, although not everybody gets them. The side effects are usually not serious or long-lasting. Many of the adverse effects seen during ivermectin treatment are actually caused by the body’s immune and inflammatory response to dying parasites (known as the Mazzotti-type reaction) rather than by direct toxicity of the drug itself. Side effects may be more common and more severe in patients infected with multiple types of parasites, particularly in those with Loa loa co-infection.

Allergic and Serious Skin Reactions

Side Effects by Indication

The side effects of ivermectin are grouped below according to the condition being treated, as the adverse effect profile differs significantly depending on the type of parasitic infection.

Intestinal Strongyloidiasis

Reported Side Effects

The following have been observed in patients treated for strongyloidiasis

  • Unusual weakness or fatigue (asthenia)
  • Loss of appetite
  • Abdominal pain
  • Constipation or diarrhoea
  • Nausea or vomiting
  • Drowsiness or dizziness
  • Tremor or shaking

In patients with strongyloidiasis, adult roundworms may be visible in the stool during or after treatment. This is a normal and expected part of the treatment process.

Lymphatic Filariasis (Wuchereria bancrofti)

Frequently Reported

Commonly observed during treatment for lymphatic filariasis (Mazzotti-type reactions)

  • Sweating or fever
  • Headache
  • Unusual weakness or fatigue
  • Pain in muscles, joints, or multiple body sites
  • Loss of appetite, nausea, or stomach pain
  • Cough or sore throat
  • Discomfort during breathing
  • Orthostatic hypotension (feeling dizzy or faint when standing)
  • Chills
  • Dizziness
  • Testicular pain or discomfort

These reactions are largely attributable to the immune response triggered by the death of microfilariae in the bloodstream and tissues. They tend to occur within the first few days of treatment and are usually self-limiting. The severity of these reactions generally correlates with the microfilarial load – patients with higher parasite burdens tend to experience more pronounced symptoms.

Scabies

Reported Side Effects

Observed in patients treated for scabies

  • Temporary worsening of itching at the beginning of treatment (this usually does not last long and is caused by the immune response to dying mites)

Patients with Heavy Loa loa Infection

Serious Reactions (Loa loa Co-infection)

These may occur in patients with heavy Loa loa microfilaraemia

  • Abnormal brain function (encephalopathy)
  • Neck or back pain
  • Subconjunctival haemorrhage (bleeding in the whites of the eyes)
  • Shortness of breath
  • Urinary or faecal incontinence
  • Difficulty standing or walking
  • Changes in mental status
  • Drowsiness, confusion, or coma
  • Unresponsiveness to other people

Patients with Onchocerciasis (River Blindness)

Mazzotti Reactions

These may occur in patients treated for onchocerciasis and are related to the immune response to dying microfilariae

  • Itching or skin rash
  • Joint or muscle pain
  • Fever
  • Nausea or vomiting
  • Swollen lymph nodes
  • Peripheral oedema (swelling of hands, ankles, or feet)
  • Diarrhoea
  • Dizziness
  • Hypotension (low blood pressure)
  • Tachycardia (rapid heart rate)
  • Headache or fatigue
  • Visual changes and other eye problems (including infection, redness, unusual sensations)
  • Subconjunctival haemorrhage or swollen eyelids
  • Worsening of asthma

Other Reported Side Effects (All Indications)

Rare or Uncommon

Reported across various indications

  • Liver disease (acute hepatitis)
  • Changes in laboratory tests (elevated liver enzymes, increased blood bilirubin, increased eosinophil count)
  • Blood in the urine (haematuria)
  • Reduced consciousness or coma (typically associated with overdose or Loa loa co-infection)

If you experience any side effects, including any not listed in this article, tell your doctor or pharmacist. You can also report suspected side effects directly to your national medicines regulatory authority (for example the EMA in Europe, FDA MedWatch in the United States, or the MHRA Yellow Card Scheme in the United Kingdom) to help continuously monitor the benefit-risk balance of ivermectin.

How Should Ivermectin Medical Valley Be Stored?

Quick Answer: Store Ivermectin Medical Valley out of the sight and reach of children. Keep the tablets in the original packaging to protect from light. No special temperature requirements. Do not use after the expiry date printed on the packaging. Dispose of unused medicine through your pharmacy – do not throw it in household waste or flush it down the drain.

Keep this medicine out of the sight and reach of children. Do not use Ivermectin Medical Valley after the expiry date printed on the blister pack, bottle, or carton after “EXP”. The expiry date refers to the last day of that month.

  • Temperature: No special temperature storage requirements.
  • Light protection: Store in the original packaging to protect from light, as ivermectin is light-sensitive.
  • Moisture: Keep blister packs sealed until ready to use. The HDPE bottle contains silica gel as a desiccant – do not remove it.

Do not dispose of medicines via wastewater or household waste. Ask your pharmacist how to dispose of medicines you no longer use. These measures will help to protect the environment. Pharmaceutical waste can contaminate waterways and harm aquatic organisms, so responsible disposal is important.

What Does Ivermectin Medical Valley Contain?

Quick Answer: Each Ivermectin Medical Valley tablet contains 3 mg of ivermectin as the active substance. The inactive ingredients are microcrystalline cellulose (E460), pregelatinised maize starch, citric acid (E330), butylated hydroxyanisole, and magnesium stearate (E470b). The tablets are round, white, and unscored.

Active Substance

The active substance is ivermectin. Each tablet contains 3 mg of ivermectin. Ivermectin is a semi-synthetic derivative of avermectin B1, consisting of a mixture of at least 80% 22,23-dihydroavermectin B1a and no more than 20% 22,23-dihydroavermectin B1b. The molecular formula of the major component (B1a) is C48H74O14, with a molecular weight of 875.1 g/mol.

Inactive Ingredients (Excipients)

  • Microcrystalline cellulose (E460) – a common tablet binder and filler
  • Pregelatinised maize starch – acts as a disintegrant to help the tablet break down
  • Citric acid (E330) – used as a pH adjuster
  • Butylated hydroxyanisole (BHA) – an antioxidant that helps prevent degradation
  • Magnesium stearate (E470b) – a lubricant used in tablet manufacturing

Appearance and Pack Sizes

Ivermectin Medical Valley tablets are round, white, and have no markings (unscored). They are available in blister packs containing 1, 4, 8, 10, 12, or 20 tablets, or in HDPE bottles containing 250 tablets with silica gel as a desiccant. Not all pack sizes may be marketed in all countries.

Manufacturer

The marketing authorisation holder is Medical Valley Invest AB, based in Sweden. The product is manufactured by Laboratorios Liconsa, S.A. in Azuqueca de Henares, Spain, and by Medical Valley Invest AB in Sweden.

Frequently Asked Questions About Ivermectin Medical Valley

Ivermectin Medical Valley is an antiparasitic medicine used to treat three conditions: intestinal strongyloidiasis (infection with the roundworm Strongyloides stercoralis), microfilaraemia due to lymphatic filariasis caused by Wuchereria bancrofti, and scabies (infestation with the mite Sarcoptes scabiei). It should only be taken when a doctor has diagnosed or strongly suspects a parasitic infection. Ivermectin treats existing infections but does not prevent new ones.

Take all prescribed tablets at the same time with water on an empty stomach. You should not eat any food within two hours before or after taking the tablets, as food may affect how the drug is absorbed. Children under 6 years of age should have the tablets crushed before swallowing. Treatment is usually a single dose, though your doctor may recommend a repeat dose for scabies (within 8–15 days) or periodic dosing for lymphatic filariasis (every 6 or 12 months).

The effect of food on ivermectin absorption is not fully characterised. Taking ivermectin with a high-fat meal has been shown to significantly increase its bioavailability (the amount absorbed into the bloodstream), potentially leading to higher-than-intended drug levels and an increased risk of side effects. To ensure consistent and predictable absorption, ivermectin should be taken on an empty stomach – avoid eating for at least 2 hours before and after taking the tablets.

Ivermectin should only be taken during pregnancy if clearly necessary, as determined by your doctor after weighing the benefits against the potential risks. Animal studies have shown teratogenic effects at high doses. If you are breastfeeding, your doctor may choose to delay treatment until one week after delivery, as ivermectin passes into breast milk. However, the WHO considers single-dose ivermectin compatible with breastfeeding for most indications. Always discuss your situation with your doctor before taking any medicine during pregnancy or while breastfeeding.

The Mazzotti reaction is an inflammatory response that occurs when microfilariae (immature parasitic worms) are killed by antiparasitic treatment. It is not a direct side effect of ivermectin itself but rather the body’s immune reaction to the release of proteins and other substances from dying parasites. Symptoms can include fever, itching, rash, joint pain, headache, swollen lymph nodes, hypotension, and tachycardia. The severity tends to correlate with the parasite burden. The Mazzotti reaction is most commonly associated with treatment of onchocerciasis and lymphatic filariasis.

After taking ivermectin for scabies, it takes approximately 4 weeks to determine whether the treatment has been fully effective. The itching may temporarily worsen at the beginning of treatment as the mites die and trigger an immune response, but this usually settles within a few days. If scabies symptoms persist after 4 weeks, your doctor may prescribe a second dose. It is also important to treat all household members and close contacts simultaneously and to wash all clothing, bedding, and towels in hot water to prevent re-infestation.

References

  1. European Medicines Agency (EMA). Ivermectin – Summary of Product Characteristics. Available from: EMA.
  2. World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd List. Geneva: WHO; 2023.
  3. Crump A, Ōmura S. Ivermectin, ‘wonder drug’ from Japan: the human use perspective. Proc Jpn Acad Ser B Phys Biol Sci. 2011;87(2):13–28. doi:10.2183/pjab.87.13.
  4. Henriquez-Camacho C, Gotuzzo E, Echevarria J, et al. Ivermectin versus albendazole or thiabendazole for Strongyloides stercoralis infection. Cochrane Database Syst Rev. 2016;(1):CD007745. doi:10.1002/14651858.CD007745.pub3.
  5. Ottesen EA, Duke BOL, Karam M, Behbehani K. Strategies and tools for the control/elimination of lymphatic filariasis. Bull World Health Organ. 1997;75(6):491–503.
  6. Rosumeck S, Nast A, Dressler C. Ivermectin and permethrin for treating scabies. Cochrane Database Syst Rev. 2018;(4):CD012994. doi:10.1002/14651858.CD012994.
  7. Gardon J, Gardon-Wendel N, Demanga-Ngangue, Kamgno J, Chippaux JP, Boussinesq M. Serious reactions after mass treatment of onchocerciasis with ivermectin in an area endemic for Loa loa infection. Lancet. 1997;350(9070):18–22. doi:10.1016/S0140-6736(96)11094-1.
  8. British National Formulary (BNF). Ivermectin. London: BMJ Group and Pharmaceutical Press; 2025.
  9. U.S. Food and Drug Administration (FDA). Stromectol (ivermectin) – Prescribing Information. Available from: FDA.
  10. World Health Organization (WHO). Guideline: Alternative Mass Drug Administration Regimens to Eliminate Lymphatic Filariasis. Geneva: WHO; 2017.

Editorial Team

This article was written and reviewed by the iMedic Medical Editorial Team, comprising licensed specialist physicians with expertise in infectious disease, tropical medicine, parasitology, and clinical pharmacology.

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