Intestinal parasites such as parasitic worms infect more than one-fourth of the world's population, according to the World Health Organization. These infections result in disease, disability and death. Although there are more than 20 different species of parasitic worms that infect humans, almost all of them can be treated with one of five common prescription drugs. Medications are also available for infections of parasites other than worms.
Threadworm, roundworm, whipworm and hookworm infections are often first treated with mebendazole, which can safely be given to adults and children older than 2 years of age. The usual dose consists of 100mg given twice a day for three days, according to the World Health Organization, or WHO.
Albendazole is another commonly used drug to treat hookworm, threadworm, trichinosis, whipworm and ascariasis in adults and children older than 2 years. This drug is also used in conjunction with surgery in severe cases of tapeworm infection. Albendazole is usually administered as 800mg per day, divided into multiple doses, for 28 days, as recommended by WHO.
Diethylcarbamazine is effective on a smaller selection of worms, including visceral larva migrans, lymphatic filariasis, onchocerciasis and loiasis. WHO indicates that this drug can be safely given to adults and children of all ages, starting at 1mg per day and increasing to 6mg per day for 21 days.
The preferred medication used to treat onchocerciasis is ivermectin, which is also effective against several other species of roundworms, threadworms and pinworms. Ivermectin is administered as a single dose of 150mcg per kilogram of body weight and is safe for adults and children of all ages, according to WHO recommendations.
Praziquantel is the preferred medication to treat schistosome infection and is also highly effective against most tapeworms and flukeworms. The drug can be safely given to adults and children of all ages, usually as 40mg per kilogram body weight, divided into two doses given four to six hours apart, explains the WHO.
Besides parasitic worms, human can also be infected by single-celled parasites such as Giardia and Trichomonas vaginalis. Both of these microscopic parasites can be treated with metronidazole.
The hormone prednisone is administered for severe toxocariasis and trichinosis infections. If the infection causes severe anemia, patients may also be treated with iron. Additionally, pain-relievers, antibiotics, anti-inflammatories, and antihistamines may also be given to patients to alleviate secondary symptoms caused by infection.
In some cases of infection surgery may be required for effective treatment. The Guinea worm can only be effectively treated by surgery, and some roundworm infection may cause obstructions in the intestinal tract or other organs that require surgical removal.