Diphenhydramine As Aid for Anthelmintic (De-Worming) Drugs

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Diphenhydramine is an antihistamine drug. It is commonly indicated for skin allergies, hay fever, in coughs associated with allergies and rarely, as an anti-emetic. Surprisingly, diphenhydramine is also used as an aid for de-worming medications. Read on.

Common anthelmintic drugs include mebendazole (Antiox), piperazine (Adrenocol), pyrantel pamoate (Combantrin), oxantel pamoate (Quantrel) and albendazole (Zentel). These medications are used for single or mixed worm infestations. While some of these drugs need prescriptions like oxantel and albendazole, pyrantel and mebendazole can be bought as OTC medications.

Worm infestation background

Helminth’s or worm’s infestation is also known as worm invasion. Although, it can be refer to as infection, worm invasion isn’t really infection since worm infestations are caused by parasites that live and feed within the body. An infection causes antigen antibody reaction which prevents future occurrence as in colds for instance. Individuals who are always exposed to virus causing colds develop immunity to it; on the other hand, the body won’t build resistance against any parasite. Bacteria, virus and fungus cause infection and not parasitic worms.

Since worm invasion can originate from habits of thumb sucking, licking fingers or placing an untidy hand in the mouth, it is very common in children under five years of age. In the adults, causes of parasitic infestations can be from poor sanitation, contaminated food or water and in an unhygienic environment.

According to shapes, there are three types of parasitic worms involved: the Trematodes which include the flukes as schistosomiasis and liver flukes; the Cestodes which include the tapeworms as solium, saginata, and echinococcus ; and the Nematodes which include the Ascaris lumbricoides, Enterobius vermicularis and the Ancylostoma duodenale.

Symptoms of parasitic worm invasion depend on the type of the worm, the severity of invasion and its affecting site. For instance, threadworm infestation may include irritability, grinding teeth in sleep, or a loss of appetite. Hook worms on the other hand, causes skin rash and in heavy invasion may result to anemia. However, summing it all up the following are common signs of worm infestations:

  • Skin rashes
  • Abdominal pains
  • Anemia
  • Poor appetite
  • Sneezing, cough, asthma
  • Eosinophilia
  • Headaches
  • Nervousness
  • Vomiting
  • Epilepsy
  • Grinding of teeth
  • Bedwetting in children
  • Restlessness at night
  • Lack of concentration
  • Growth retardation
  • Anal or vaginal itch which is worst at night

The danger with anthelmintics or de-worming drugs

As cited mebendazole and pyrantel are usually OTC anthelmintic medications. People buy these types during signs of worm invasions not minding the severity of its infestation. Although, de-worming drugs may work on any parasitic worms, the seriousness of its invasion must be considered. Worm infestation with the minimal kind maybe treated with a de-worming drug without any problems but treating a serious worm invasion can be dangerous.

A single anthelmintic tablet can cause panic for the parasitic worms. Imagine a bomb being dropped down unto a hundred of rats. As an instinct, these creatures will ran and look for a way out. In the case of worms, they will find exit through the ears, the nose, the mouth and even through the eyes.

Diphenhydramine uses and side-effects

Diphenhydramine hydrochloride is an FGA or first-generation antihistamine commonly used to treat skin allergies, hay fever and other symptoms of allergies associated with cough and colds. In psychiatric medicine, it is used to treat phenothiazine drug-induced abnormal muscle movement by controlling the symptoms. Diphenhydramine is also used as a drug for motion sickness because of its anti-emetic property. It is indicated as a sleep aid and sometimes used to control tremors in Parkinson's disease.

While the main untoward effect of diphenhydramine is sedation, other side-effects include restlessness, nervousness, difficulty sleeping, blurry or double vision, ringing in the ears, headache and convulsions.

Image source

Common diphenhydramine brand names and availability:

Benadryl 25 and 50 mg cap; 12.5mg per 5ml syrup; 50mg per 1 ml vial (Johnson and Johnson)

Alerace 25mg cap (ace)

Allerin AH 25mg soft gelatin cap; 12.5 mg syrup (United laboratory)

Valdres 25 mg tablet (Pharos)

Biogenerics Diphenhydramine 12.5mg syrup (Pascual)

Diphenhydramine as aid for anthelmintic medications

Anthelmintic drugs like pyrantel pamoate works by paralyzing the parasitic worms commonly roundworms and pinworms, but for precaution and for severe or mixed infestations, physicians prescribe diphenhydramine before indicating a de-worming drug. Diphenhydramine is taken for two days before the administration of a de-worming drug. This is to sedate the parasitic worms. In children from two to twelve years of age, diphenhydramine with the strength of 12.5 mg per 5ml is given 1 tsp (5ml) to 2 tsp (10ml) three times a day for two days. In adults, the usual dose is 25mg capsule three times a day for two days, same with the dosage regimen of the child. After the final dose of diphenhydramine, a single dose of a de-worming drug as mebendazole or pyrantel can be given at night before bedtime.


The dosage regimen concerning treating worm infestations vary. Doctors have different approach with this matter and while anthelmintic drugs are readily available as OTC, it is still essential to consult a health professional before engaging into de-worming, especially with serious worm invasions.

© Phoenix Montoya @ April 6, 2011


  1. http://www.mims.com/Page.aspx?menuid=mimssearch&searchcategory=AUTODET&searchstring=diphenhydramine+hydrochloride&CTRY=PH
  2. http://archives.chennaionline.com/health/Homoeopathy/2006/03homoeo79.asp
  3. http://www.encyclopedia.com/topic/Diphenhydramine.aspx
  4. Philippine Pharmaceutical Directory 5th edition

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