Anthelmintics : Drugs, their Uses, Side effects

Anthelmintics are drugs that either kill (vermicide) or expel (vermifuge) infesting helminths.

Helminthiasis is prevalent globally (1/3rd of world’s population harbours them), but is more common in developing countries with poorer personal and environmental hygiene.

Multiple infestations in the same individual are not infrequent. In the human body, g.i.t. is the abode of many helminths, but some also live in tissues, or their larvae migrate into tissues. They harm the host by depriving him of food, causing blood loss, injury to organs, intestinal or lymphatic obstruction and by secreting toxins.

Helminthiasis is rarely fatal, but is a major cause of ill health.

The choice of drug for each worm infestation is based not only on efficacy, but also on lack of side effects/ toxicity, ease of administration (preferably single dose) and low cost. Develop ment of resistance has not been a problem in the clinical use of Anthelmintics.

Choice of drugs for Helminthiasis

• ROUNDWORM (Ascaris lumbricoides)

First choice drugs – Mebendazole, Albendazole, Pyrantel

• HOOKWORM (Ancylostoma duodenale , Necator americanus)

First choice drugs– Pyrantel, Mebendazole, Albendazole Mebendazole, Albendazole

• PIN WORM (Enterobius vermicularis)

First choice drugs– Pyrantel, Mebendazole, Albendazole

• THREAD WORM (Strongyloides stercoralis)

First choice drugs- Ivermectin

• WHIPWORM (Trichuris trichiura)

First choice drugs– Mebendazole

• Trichinella spiralis

First choice drugs– Albendazole

• FILARIA (Wuchereria bancrofti, Brugia malayi)

First choice drugs– Diethylcarbamazine, Ivermectin

• GUINEA WORM (Dracunculus medinensis)

First choice drugs– Metronidazole

• TAPEWORM (Taenia saginata, Taenia solium, Hymenolepis nana, Neurocysticercosis)

First choice drugs– Praziquantel, Niclosamide , Albendazole.

• HYDATID DISEASE (Echinococcus granulosus, E. multilocularis)

First choice drugs– Albendazole

Knowledge of Drugs in detail

• Mebendazole (MBZ) is a medication used to treat a number of parasitic worm infestations. This includes ascariasis, pinworm disease, hookworm infections, guinea worm infections, hydatid disease, and giardia, among others. It is taken by mouth.

Common side effects include headache, vomiting, and ringing in the ears.If used at large doses it may cause bone marrow suppression. It is unclear if it is safe in pregnancy.

• Albendazole is a medication used for the treatment of a variety of parasitic worm infestations. It is useful for giardiasis, trichuriasis, filariasis, neurocysticercosis, hydatid disease, pinworm disease, and ascariasis, among others. It is taken by mouth.

Common side effects include nausea, abdominal pains, and headaches. Potentially serious side effects include bone marrow suppression which usually improves on stopping the medication. Liver inflammation has been reported and those with prior liver problems are at greater risk. It may cause harm if taken by pregnant women.

• Pyrantel is a medication used to treat a number of parasitic worm infections. This includes ascariasis, hookworm infections, enterobiasis (pinworm infection), trichostrongyliasis, and trichinellosis. It is taken by mouth.

Side effects include nausea, headache, dizziness, trouble sleeping, and rash. A lower dose should be used in people with liver disease while it does not appear to be harmful during pregnancy, it has not been studied for this use. It is unclear if it is safe for use during breastfeeding. It is in the antihelmintic family of medications. It works by paralyzing worms.

• Ivermectin – This medication is used to treat certain parasitic roundworm infections. Curing parasitic infections helps to improve your quality of life. In people with weakened defense (immune) systems, curing roundworm infections can reduce the risk of developing a severe or life-threatening infection. It works by paralyzing and killing parasites.

How to use Ivermectin??

Take this medication by mouth with a full glass of water (8 ounces or 240 milliliters) on an empty stomach at least 1 hour before a meal. Ivermectin is usually taken as a single dose or series of doses, or as directed by your doctor.

• Diethylcarbamazine (DEC) is a medication used in the treatment of filariasis including lymphatic filariasis, tropical pulmonary eosinophilia, and loiasis. It may also be used for prevention of loiasis in those at high risk. While it has been used for onchocerciasis (river blindness), ivermectin is preferred. It is taken by mouth.

Common side effects include itching, facial swelling, headaches, and feeling tired. other side effects include vision loss and dizziness. It is a recommended treatment in pregnancy and appears to be safe for the baby.

It is made from 4-methyl-piperazine.

• Metronidazole is an antibiotic that is used to treat a wide variety of infections. It works by stopping the growth of certain bacteria and parasites.

This antibiotic treats only certain bacteria and parasitic infections. It will not work for viral infections (such as common cold, flu).

Metronidazole may also be used with other medications to treat certain stomach/ intestinal ulcers caused by a bacteria (H. pylori).

How to use Metronidazole

Take this medication by mouth as directed by your doctor. To prevent stomach upset, take this medication with food or a full glass of water or milk. The dosage is based on your medical condition and response to treatment.

• praziquantel is now the most favoured drug against all forms of schistosomiasis, and against many other helminth infections. Administration of praziquantel typically causes paralysis of susceptible worms, or damage to their tegument, making them more vulnerable to host enzymes or antibody-dependent immune effector mechanisms.

• Niclosamide may be taken on an empty stomach (either 1 hour before or 2 hours after a meal). However, to prevent stomach upset, it is best taken after a light meal (for example, breakfast).

Niclosamide tablets should be thoroughly chewed or crushed and then swallowed with a small amount of water. If this medicine is being given to a young child, the tablets should be crushed to a fine powder and mixed with a small amount of water to form a paste.

For patients taking this medicine for beef tapeworms or broad or fish tapeworms:

• To help clear up your infection completely, take this medicine exactly as directed by your doctor. Usually one dose is enough.

However, in some patients a second dose of this medicine may be required to clear up the infection completely.

For patients taking this medicine for dwarf tapeworm:

• To help clear up your infection completely, keep taking this medicine for the full time of treatment (usually 7 days).