Ivermectin

Parasitic Infections

Oral ivermectin is used to treat certain infections caused by parasitic worms, including:

• Intestinal strongyloidiasis: An infection caused by the Strongyloides stercoralis roundworm.
• Onchocerciasis: An infection caused by the Onchocerca volvulus roundworm, often referred to as river blindness.

Skin and Hair Conditions

Topical forms of ivermectin are used to treat conditions affecting the skin or hair, such as:

• Head lice: Lotions are applied to the scalp and hair to treat lice infestations.
• Rosacea: Creams are used to treat the inflammatory bumps and pimples caused by rosacea.

Mechanism of Action

Ivermectin belongs to a class of medications known as anthelmintics. It works by binding with high affinity to specific chloride channels found in the nerve and muscle cells of parasites. This binding increases the flow of chloride ions into the cells, which causes the following effects:

• Hyperpolarization: The electrical charge of the cells is altered.
• Paralysis: The parasite's muscles and nerves stop functioning correctly.
• Death: Because the parasite can no longer move or feed, it eventually dies.

Selectivity

The medication is designed to be selective, meaning it targets nerve and muscle components that are common in invertebrates, such as worms and insects. These specific channels are generally not found in humans or are protected by the blood-brain barrier, which helps limit the drug's effect on the human nervous system when taken at recommended doses.

Topical Application

When applied to the skin or scalp, ivermectin works in specific ways depending on the condition:

• Head Lice: It paralyzes the lice, preventing them from surviving or reproducing.
• Rosacea: The exact way ivermectin treats rosacea is not fully understood. It is believed to work through a combination of anti-inflammatory effects and by killing Demodex mites, which are microscopic organisms that live on the skin and may contribute to rosacea symptoms.

Common Side Effects

Common side effects of oral ivermectin may include:

• Dizziness or drowsiness
• Nausea, vomiting, or loss of appetite
• Stomach pain, diarrhea, or constipation
• Weakness or lack of energy
• Uncontrollable shaking of a part of the body

Common side effects of topical ivermectin (applied to the skin or hair) may include:

• Skin burning or stinging
• Dry skin
• Eye redness or irritation

Serious Side Effects

Contact a healthcare provider immediately if you experience any of the following serious symptoms:

• Swelling of the face, arms, hands, feet, or lower legs
• Chest pain or a rapid heartbeat
• Confusion, seizures, or loss of consciousness
• Vision changes, eye pain, or severe eye redness
• Severe skin rash, blistering, or peeling

Mazzotti Reaction

When treating certain parasitic infections, such as onchocerciasis, a reaction called the Mazzotti reaction may occur within the first few days of treatment. This is caused by the body's response to the dying parasites. Symptoms include:

• Fever and chills
• Joint or muscle pain
• Swollen or tender lymph nodes
• Itching and skin rash

COVID-19 and Misuse

The FDA has not authorized or approved ivermectin for the prevention or treatment of COVID-19 in humans or animals. Taking large doses of this medication is dangerous and can cause serious harm. Additionally, ivermectin products intended for animals should never be used by humans, as they are often highly concentrated and contain inactive ingredients that have not been evaluated for human use.

Neurological Risks

Patients with a heavy infection of the parasite Loa loa may experience serious or even fatal brain-related side effects, known as encephalopathy, after taking ivermectin. Symptoms may include neck pain, red eyes, shortness of breath, or changes in mental status. It is important to inform a healthcare provider of any travel history to regions where Loa loa is common.

Specific Populations

• Weakened Immune Systems: People with severely compromised immune systems may not respond as well to standard treatment and might require repeated doses to manage certain infections like strongyloidiasis.
• Pregnancy and Breastfeeding: Ivermectin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. The drug is excreted in low concentrations in human milk.
• Pediatric Use: The safety and effectiveness of oral ivermectin have not been established for children weighing less than 15 kg (approximately 33 pounds).

General Precautions

Ivermectin may cause dizziness, lightheadedness, or drowsiness. Caution is advised when driving, operating machinery, or performing other tasks that require alertness. For topical forms, avoid contact with the eyes, mouth, or vaginal area. If the medication comes into contact with these areas, it should be rinsed thoroughly with water.

Pregnancy

The safety of ivermectin during pregnancy has not been fully established in humans. Animal studies have indicated that high doses of the drug may lead to developmental issues, such as cleft palate, particularly when the dose is high enough to be toxic to the mother. Consequently, ivermectin is typically used during pregnancy only when the potential benefit to the mother outweighs the potential risk to the developing fetus.

Breastfeeding

Ivermectin passes into breast milk in small amounts. Clinical data suggests that less than 2% of the dose is excreted in human milk. Because the safety for newborns has not been fully determined, healthcare providers generally recommend weighing the necessity of the treatment for the mother against the potential risks to the nursing infant. It is important to inform your healthcare provider if you are breastfeeding or planning to breastfeed before starting this medication.

Oral Formulations

Ivermectin is available as a tablet to be taken by mouth. This form is typically used to treat certain parasitic infections inside the body.

Topical Formulations

For conditions affecting the skin or hair, ivermectin is available in the following forms:

• Cream: This formulation is applied directly to the skin for specific inflammatory skin conditions.
• Lotion: This form is typically applied to the scalp and hair for the treatment of head lice.

It is important to use only the specific formulation prescribed by a healthcare professional. Products intended for topical use should not be swallowed, and products intended for animal use are not safe or appropriate for humans.

FDA-Approved Uses

The FDA has approved ivermectin tablets for human use to treat specific conditions caused by parasitic worms, including intestinal strongyloidiasis and onchocerciasis. Topical versions of the drug are also FDA-approved for the treatment of external parasites like head lice and for inflammatory skin conditions such as rosacea.

Animal Formulations

Ivermectin is widely approved for use in animals to prevent heartworm disease and to treat various internal and external parasites. The FDA has issued safety communications warning that animal ivermectin products are distinct from those approved for humans. Animal drugs are often highly concentrated for large livestock and may contain inactive ingredients that have not been tested or approved for human consumption.

COVID-19 Regulatory Status

The FDA has not authorized or approved ivermectin for the prevention or treatment of COVID-19 in humans or animals. The agency has stated that current data does not show ivermectin is effective against COVID-19 and has warned consumers against using the drug for this purpose, especially formulations intended for animals. Taking large doses of ivermectin can be highly toxic and lead to serious health complications.

FDA Guidance

Ivermectin is an antiparasitic medication and is not an antiviral drug. The FDA has not approved ivermectin for use in treating or preventing COVID-19 in humans. There is currently no evidence from clinical trials that ivermectin is effective against the virus that causes COVID-19.

Potential Risks

Using ivermectin for COVID-19 carries significant health risks:

• Overdose: Taking large doses of this medication can lead to serious toxicity, resulting in symptoms such as nausea, vomiting, diarrhea, low blood pressure, allergic reactions, dizziness, seizures, coma, and death.
• Animal Products: Ivermectin products intended for animals are not the same as those for humans. Animal formulations are often highly concentrated and may contain inactive ingredients that are unsafe for human consumption.
• Interactions: Ivermectin can interact with other medications, including blood thinners like warfarin, which can increase the risk of bleeding.

Patients should consult with a healthcare professional regarding approved treatments and preventive measures for COVID-19.