Read Letter from Senior Marketing Director at Merck, Michael W. Skoien
Ivermectin (eye-ver-MEK-tin) is used in the treatment of certain worm infections. It is used to treat river blindness (onchocerciasis) and a certain type of diarrhea (strongyloidiasis). It may also be used for some other kinds of worm infections.
Ivermectin appears to work by paralyzing and then killing the offspring of adult worms. It may also slow down the rate at which adult worms reproduce. This results in fewer worms in the skin, blood, and eyes.
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For ivermectin, the following should be considered:
Allergies— Tell your doctor if you have ever had any unusual or allergic reaction to ivermectin. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.
Pregnancy— Ivermectin has not been studied in pregnant women and use of ivermectin is not recommended during pregnancy. Studies in animals given ivermectin have shown that ivermectin causes birth defects or other problems. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.
Breast-feeding— Ivermectin passes into breast milk. However, it has not been reported to cause problems in nursing babies.
Children— Studies on this medicine have been done only in adults and in children weighing 15 kilograms (kg) (33 pounds) and over, and there is no specific information comparing use of ivermectin in children weighing less than 15 kg with use in other age groups.
Older adults— Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of ivermectin in the elderly with use in other age groups.
Other medicines— Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your health care professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.
Other medical problems— The presence of other medical problems may affect the use of ivermectin. Make sure you tell your doctor if you have any other medical problems, especially:
An estimated 6 million people worldwide have taken ivermectin for various parasitic infestations. 15 No serious drug-related adverse events have been reported. Side effects of ivermectin include fever, headache, chills, arthralgia, rash, eosinophilia, and anorexia. 15 Many of these symptoms are thought to result from the death of parasites rather than as a reaction to the drug.
Ivermectin seems to be concentrated in the liver and fat tissue, with very low levels reaching the central nervous system. 20 No significant drug interactions have been reported. 21
A study of elderly nursing home patients treated for scabies infection showed an increased death rate among ivermectin-treated patients, 22 but it was noted that this finding has not been confirmed in multiple subsequent trials.
Ivermectin is not approved for treatment of scabies by the U.S. Food and Drug Administration. There are concerns regarding its use in young children and pregnant women, because there may be more drug penetrance of the immature blood-brain barrier.