Dr. Aditya Shah
Expert In Clinical Pharmacology And Drug SafetyView moreFenbendazole is the medication to treat parasitic infections due to hookworms, tapeworms, whipworms, and other such worms in animals. It belongs to the class of drugs known as anthelmintics, whose primary job is to counter parasitic infections.
For human consumption, the drug has not been approved by FDA. Scientists have found results showing positive results in treating cancerous cells, but it hasn’t received wide acceptance. It is an over-the-counter medication easily available in stores, which is also a factor for its high demand.
How It Works: The Mechanism of Action
Fenbendazole targets the energy supply of parasite by attaching itself to the “tubulin” protein, present in parasitic cells. This leads to resistance in the polymerization of “tubulin” into microtubules.
| Step | How Fenbendazole Works |
|---|---|
| 1. Targets Parasites | Fenbendazole enters the worm’s body and targets parasite cells. |
| 2. Blocks Energy Supply | It prevents worms from absorbing glucose (an energy source). |
| 3. Stops Growth | Parasites become weak and unable to survive or reproduce. |
| 4. Eliminates Worms | The dead or weakened worms are naturally removed from the body. |
These microtubules are needed for parasitic cells to absorb glucose for daily functionalities of existence. Once this is affected, parasitic cells starve and ultimately ceases to exist. Notable thing is Fenbendazole attacks majorly on invading tubulin or protein, not the host ones that are already existing. This ensures the drug affects only the problematic parasitic cells.
Targeted Intestinal Worms
Fenbendazole is not only successful in eradicating parasitic infections. But it destroys parasites at different stages of life, such as their eggs, larvae, and full-grown worms. For the same reason, it is also referred as “broad-spectrum” counter parasitic drug.
➯ Roundworms (Toxocara spp.)
Roundworms are the most common parasites affecting livestock across the globe. These are mostly found in the small intestine, taking a share of nutrients from host. Fenbendazole is highly successful in eradicating these roundworms by choking their nutrient supply. For complete treatment it takes around 3 to 4 weeks of medication.
➯ Hookworms (Ancylostoma spp.)
Hookworms bind themselves to the intestine walls. Unlike roundworms, their major food is hosts’ blood. In infants, young or animals in certain critical situation roundworms can cause anemia. Fenbendazole is effective in detaching parasitic cells and starving them to death.
➯ Whipworms (Trichuris vulpis)
Whipworms reside in large intestines and cecum. Unlike hookworms and roundworms, these are highly resistant parasites making their treatment a time taking procedure. Their eggs can survive multitude of environmental factors, making other drugs less effective. In this Fenbendazole is the best suited drug to permanently eradicate the parasite.
➯ Tapeworms (Taenia spp.)
The thing to note is that in case of tapeworms, Fenbendazole is not effective against all tapeworms. Only against specific ones such as like Taenia, it shows high efficacy. Against the most common form of tapeworm, Dipylidium caninum Fenbendazole is not prescribed. Doctors go for other anthelmintics.
Administration and Dosage
Dosage depends on the whole of factors such as intensity of infections, symptoms, earlier medical track record etc.
However, generally Fenbendazole shall be taken for 3 to 5 consecutive days, then a pause for few days and then again, the cycle is to be repeated. Daily, 1 capsule per day is usually the most common dosage.
Dosage Forms:
- Granules/Powder: Mixed with meals for better digestion. Powder is the most common form available, however.
- Suspension (Liquid): This is effective for smaller or young animals who find difficult to intake the granular form.
- Paste: Mostly for treatment of horses.
Why Multiple Days?
One can argue why it takes such long durations for Fenbendazole to treat parasites if it’s that effective. This is because with initial dose, the starving of parasitic cells begins, one can feel initial relief. To ensure that parasite cells are completely destroyed it takes few weeks’ time.
Hence, it is advised to complete the full course of medication as directed by the doctor. Withdrawing the medication does not have withdrawal symptoms but there are chances parasite might again initiate infections.
Safety and Side Effects
Fenbendazole is one of the safest drugs, with no serious side effects in most cases. The ingredients of the tablet are mostly present in the intestine; they do not get absorbed quickly by bloodstream. Thus, after performing its activity the drug is excreted along with stool or urine.
Common Side Effects
- Mild diarrhea or loose stools: This is also very rare, if it persists for more than a day, see the doctor.
- Occasional vomiting (in pets): Avoid feeding deep fried or rich in high cholesterol food items.
- Loss of appetite during the treatment period: Feed 2 to 3 times a day as usual, do not let stomach be empty for too long.
Precautions
- Dosage Checkout: As discussed earlier, the drug is easily available over the counter, without proper label as well. But while beginning it is better to take advice from a doctor or medical professional. They can guide the best dosage as per the body weight of each species.
- Existing Illnesses: During checkups, also inform the doctor about existing illnesses, any chronic issues, allergies etc.
The Rising Interest in Human Use
Till now FDA and many drug regulating bodies across nations have not approved the use of Fenbendazole for human consumption. But having said this, research have shown that the drug shows promise in treating cancerous cells in humans. Currently, for treating parasitic infection in humans, Albendazole is prescribed.
FAQ: Frequently Asked Questions
Q. How long does it take for Fenbendazole to kill worms?
In the first 1 or 2 days itself parasites begin to die, and you may experience relief. For overall eradication of eggs, larvae and all components of parasite, a week is needed.
Q. Can I give Fenbendazole to a pregnant animal?
For pregnant animals too, the drug is quite safe. But to be on the safe side, consult the doctor.
Q. Does Fenbendazole kill all types of worms?
Thought Fenbendazole is known as “broad-spectrum” counter parasite drug, but it does do it successfully for all parasites. It proves successful in treating roundworms, hookworms, and whipworms, but not for heartworms and tapeworms.
Q. Can Fenbendazole be taken on an empty stomach?
Doctors tell to consume the drug along with food. This reduces chances of stomach issues.
Q. What happens if I miss a dose?
Avoid double doses with intention to compensate the missed dose. Take help from your respective doctor.
