50 Facts About Ivermectin

Discovery and Early Uses

Ivermectin has a fascinating history, starting from its discovery to its initial applications in veterinary medicine. Let's dive into its origins and early uses.

1. Discovery: Ivermectin was discovered in 1975 by William Campbell of the Merck Institute for Therapeutic Research and Satoshi Ōmura of Kitasato University.

2. Initial Use: The first uses of ivermectin were in veterinary medicine to prevent and treat heartworm and acariasis.

3. Human Approval: Ivermectin was approved for human use in 1987.

4. Brand Names: Ivermectin is marketed under various brand names, including Sklice, Soolantra, and Stromectol.

5. Generic Name: The generic name for ivermectin is simply "ivermectin."

Mechanism of Action

Understanding how ivermectin works can help us appreciate its effectiveness against parasites. Here's a look at its mechanism of action.

6. Mechanism of Action: Ivermectin works by interfering with the nerve and muscle functions of helminths and insects. It binds to glutamate-gated chloride channels common to invertebrate nerve and muscle cells, increasing the flow of chloride ions and hyper-polarizing the cell membranes, which paralyzes and kills the invertebrate.

7. Glutamate-Gated Chloride Channels: The drug binds to glutamate-gated chloride channels common to invertebrate nerve and muscle cells, increasing the flow of chloride ions and hyper-polarizing the cell membranes.

8. Safety for Mammals: Ivermectin is safe for mammals at normal therapeutic doses because mammalian glutamate-gated chloride channels only occur in the brain and spinal cord, and the causative avermectins usually do not cross the blood–brain barrier.

9. Blood–Brain Barrier: The avermectins in ivermectin do not cross the blood–brain barrier, reducing the risk of adverse effects in mammals.

10. Invertebrate Specificity: The mechanism of action of ivermectin is specific to invertebrates, making it effective against a wide range of parasites without harming mammals.

Parasitic Infections Treated

Ivermectin is a versatile medication used to treat various parasitic infections. Here are some of the conditions it can address.

11. Parasitic Infections Treated: Ivermectin is used to treat a variety of parasitic infections including head lice, onchocerciasis (river blindness), strongyloidiasis, ascariasis, trichuriasis, and enterobiasis.

12. Topical Use: Ivermectin cream is indicated for the treatment of inflammatory lesions associated with rosacea, while an over-the-counter lotion is used for the topical treatment of head lice infestations in patients ≥6 months of age.

13. Oral Administration: Ivermectin tablets are approved by the FDA to treat intestinal strongyloidiasis and onchocerciasis.

14. Systemic Use: Systemic ivermectin therapy is used internationally for the treatment of various tropical diseases, including filariasis, cutaneous larva migrans, and Loa loa infection.

15. Common Parasitic Infections Treated: Ivermectin is commonly used to treat strongyloidiasis of the intestinal tract and onchocerciasis (river blindness).

Global Impact and Recognition

Ivermectin's impact on global health has been profound, earning it significant recognition and widespread use.

16. WHO Essential Medicines List: Ivermectin is on the World Health Organization’s list of essential medicines due to its effectiveness in combating parasitic illnesses.

17. Nobel Prize Recognition: The discovery and applications of ivermectin were recognized with the 2015 Nobel Prize in Physiology or Medicine awarded to William Campbell and Satoshi Ōmura.

18. Global Usage: Over four billion doses of ivermectin have been administered to patients in Africa and Central and South America, making it one of the most widely used medications globally.

19. Worldwide Prescriptions: In 2022, ivermectin was the 314th most commonly prescribed medication in the United States, with more than 200,000 prescriptions.

20. Public Health Initiative: The distribution of ivermectin as part of public health initiatives has been instrumental in controlling and eliminating parasitic diseases in endemic areas.

COVID-19 Research and Controversies

Ivermectin has also been studied for its potential use in treating COVID-19, sparking debates and controversies.

21. FDA Approval Status: The FDA has approved ivermectin for specific parasitic infections but not for the treatment or prevention of COVID-19.

22. COVID-19 Research: Despite the FDA’s stance, ivermectin has been studied for its potential use in treating COVID-19 due to its ability to inhibit SARS-CoV-2 in vitro.

23. In Vitro Inhibition: Achieving 50% inhibition of SARS-CoV-2 in vitro requires an estimated oral dose of 7.0 mg/kg, which is significantly higher than the maximum FDA-approved dosage.

24. Statistical Significance in COVID-19 Studies: Meta-analyses of high-quality studies indicate that ivermectin may reduce mortality by 40% when given early in an infection, though this benefit is just barely statistically significant (p = 0.04).

25. Indirect Benefit Hypothesis: Some researchers suggest that ivermectin’s benefit in treating COVID-19 might come indirectly by ridding the body of parasites, which could prevent hyperinfection syndrome when corticosteroids are administered.

Dosage and Administration

Knowing the correct dosage and administration methods is crucial for the safe and effective use of ivermectin.

26. Dosage Forms: Ivermectin is available as oral tablets (e.g., Stromectol) and topical creams/lotions.

27. Storage Requirements: Ivermectin tablets should be stored at temperatures below 30°C (86°F).

28. LD50 Range: The lethal dose 50 (LD50) range for ivermectin in humans is approximately 2.02–43.24 mg/kg, which is far more than its FDA-approved usage (a single dose of 0.150–0.200 mg/kg).

29. Treatment Delays and Dosage Size: The difference in efficacy between geographic areas can be partly explained by treatment delays and dosage size, with earlier administration and higher doses showing better results.

30. Ventilator Use Reduction: Studies indicate that ivermectin reduces the risk of needing a mechanical ventilator by 48%, with a 95% confidence interval of 38% to 78%.

Economic and Public Health Impact

Ivermectin has not only improved health outcomes but also had significant economic and public health impacts.

31. Economic Impact: The widespread use of ivermectin has also had economic benefits by reducing the cost associated with treating parasitic diseases, which can be a significant burden on healthcare systems.

32. Community-Based Distribution: In some regions, ivermectin is distributed through community-based programs to ensure widespread coverage and reduce the burden of parasitic diseases.

33. Global Health Impact: Ivermectin has significantly impacted global health by reducing the incidence of parasitic diseases in developing countries.

34. Public Awareness: Public awareness campaigns about the use and benefits of ivermectin are essential to ensure that patients understand its indications, dosages, and potential side effects.

35. WHO Recommendations: The World Health Organization recommends ivermectin for the treatment of onchocerciasis and lymphatic filariasis due to its high efficacy and safety profile.

Future Directions and Research

Research into ivermectin continues, exploring new applications and potential benefits.

36. Research Continuation: Despite its established use, research into ivermectin continues to explore new applications, including its potential use in treating COVID-19 and other infectious diseases.

37. Clinical Trials: Ongoing and future clinical trials will help determine the efficacy and safety of ivermectin in various clinical settings, including its potential use in treating COVID-19.

38. Regulatory Approval Process: The regulatory approval process for ivermectin involves rigorous testing to ensure its safety and efficacy for human use, which is a critical step in making it available as a treatment option.

39. Off-Patent Status: As an off-patent medication, ivermectin is now available at a lower cost, making it more accessible to patients in need.

40. Future Directions: Further research into ivermectin’s mechanisms of action and potential applications will continue to shape its role in modern medicine, potentially leading to new treatments for a variety of diseases.

Miscellaneous Facts

Here are some additional interesting facts about ivermectin that didn't fit into the previous categories.

41. Animal Use: Some forms of animal ivermectin are approved to prevent heartworm disease and treat certain internal and external parasites in animals, but these products are different from those used in humans and must be used as labeled or prescribed.

42. Rosacea Treatment: Ivermectin cream is indicated for the treatment of inflammatory lesions associated with rosacea.

43. Head Lice Infestation: An over-the-counter ivermectin lotion is commercially available and indicated for the topical treatment of head lice infestations in patients ≥6 months of age.

44. Comparison with Other Treatments: Ivermectin shows a benefit of 71% (range 61% to 77%) in treating COVID-19, which is better than the 20% benefit (range 11% to 27%) from Gilead Sciences’ FDA-approved Veklury (remdesivir) and the 34% benefit (range –13% to 62%) from Merck’s COVID treatment molnupiravir.

45. High-Quality Study Review: An extensive literature review of high-quality ivermectin–COVID studies indicates that the drug reduces mortality by 40%, which is just barely statistically significant (p = 0.04).

46. Prejudice in Endorsement: Despite the statistical significance, some researchers refrain from endorsing the use of ivermectin for COVID-19 due to potential biases and the need for further evidence.

47. Indirect Benefit Hypothesis: Some researchers suggest that ivermectin’s benefit in treating COVID-19 might come indirectly by ridding the body of parasites, which could prevent hyperinfection syndrome when corticosteroids are administered.

48. Geographic Variability in Efficacy: The benefit of ivermectin in treating COVID-19 appears to vary by geographic area, with a higher benefit observed in areas with low parasitic prevalence (72%) compared to high prevalence areas (55%).

49. Treatment Delays and Dosage Size: The difference in efficacy between geographic areas can be partly explained by treatment delays and dosage size, with earlier administration and higher doses showing better results.

50. Ventilator Use Reduction: Studies indicate that ivermectin reduces the risk of needing a mechanical ventilator by 48%, with a 95% confidence interval of 38% to 78%.

The Impact of Ivermectin

Ivermectin has proven itself as a versatile and effective antiparasitic medication. From treating parasitic infections like onchocerciasis and strongyloidiasis to its potential in COVID-19 research, this drug has made a significant mark in global health. Its discovery earned a Nobel Prize, highlighting its importance. With over four billion doses administered worldwide, ivermectin's reach is vast. It's on the WHO's list of essential medicines, underscoring its critical role in combating parasitic diseases. While its use in treating COVID-19 remains under study, the drug's established benefits in other areas are undeniable. Affordable and widely available, ivermectin continues to be a cornerstone in treating parasitic infections, improving the lives of millions. Ongoing research may unlock even more potential uses, ensuring ivermectin remains a vital tool in modern medicine.