Action And Clinical Pharmacology: Thiabendazole is an anthelmintic for the treatment of various nematode infections of man.
Thiabendazole provides systemic treatment for cutaneous larva migrans. It causes worms to be eliminated spontaneously from the cutaneous blister or it eases their manual removal. In some instances the devitalized worm is not expelled and encystment with lysis occurs.
In some patients, the drug has been useful in the treatment of trichinosis.
Thiabendazole is vermicidal/vermifugal against Ascaris lumbricoides (roundworm), Stronglyoides stercoralis (threadworm), Necator americanus and Ancylostoma duodenale (hookworm), Trichuris trichiura (whipworm), and Enterobius vermicularis (pinworm). It also possesses ovicidal effects (roundworm, hookworm, pinworm), and interferes with the embryonation and development of larval stages (threadworm). It may inhibit the subsequent development of those eggs or larvae which are passed in the feces.
Indications And Clinical Uses: Intestinal parasitosis (whether encountered singly or in combintaion), Strongyloidiasis, Ascariasis (large roundworm disease), Uncinariasis (hookworm disease-both Necator americanus and Ancylostoma duodenale), Trichuriasis (whipworm disease).
Cutaneous larva migrans (creeping eruption).
Trichinosis: In trichinosis, relief of symptoms and fever and reduction of eosinophilia have followed use of thiabendazole during the invasion stage of the disease. However, the effect of thiabendazole on the viability of the larvae which have migrated to muscle is incompletely defined, and not all patients respond to the recommended dosage of the drug.
Although not indicated as primary therapy, when Enterobiasis (pinworm) occurs with any of the conditions listed under Indications, additional therapy is not required for most patients.
Thiabendazole should be used only in the following infestations when more specific therapy is not available, or cannot be used, or when further therapy with a second agent is desirable: uncinariasis (hookworm: Necator americanus and Ancylostoma duodenale); trichuriasis (whipworm); ascariasis (large roundworm).
Contra-Indications: History of hypersensitivity reaction to thiabendazole.
Manufacturers’ Warnings In Clinical States: Occupational Hazards: Thiabendazole may impair the alertness in some patients: operation of automobiles and other activities made hazardous by diminished alertness should be avoided.
If hypersensitivity reactions occur, the drug should be discontinued immediately and not resumed. Erythema multiforme has been associated with thiabendazole therapy: In severe cases (Stevens-Johnson syndrome) fatalities have occurred.
Pregnancy and Lactation: Safety for the use of this drug in pregnancy and lactation has not been established.
Reproduction studies of successive generations of mice, rats, swine, rabbits, cattle and sheep have shown no fetal abnormalities that could be related directly to thiabendazole (see Pharmacology).
Thiabendazole is excreted in the milk of cattle.
Precautions: Ideally, supportive therapy is indicated for anemic, dehydrated or malnourished patients prior to initiation of the anthelmintic therapy.
Thiabendazole is not suitable for the treatment of mixed infections with ascaris because it may cause these worms to migrate.
Thiabendazole should be used only in patients in whom susceptible worm infestation has been diagnosed and should not be used prophylactically.
Since thiabendazole is metabolized in the liver and excreted by the kidneys, hepatic and renal function should be carefully monitored in patients with dysfunction of these organs.
Thiabendazole may compete with other drugs, such as theophylline, for sites of metabolism in the liver, thus elevating the serum levels of such compounds to potentially toxic levels. Therefore, when concomitant use of thiabendazole and xanthine derivatives is anticipated, it may be necessary to monitor blood levels and/or reduce the dosage of such compounds. Such concomitant use should be administered under careful medical supervision.
Adverse Reactions: Side effects most frequently encountered are anorexia, nausea, vomiting and dizziness. Less frequently, diarrhea, epigastric distress, pruritus, weariness, drowsiness, giddiness and headache have occurred.
Side effects which have occurred rarely, include: tinnitus, collapse, abnormal sensation in eyes, blurring of vision, hyperirritability, numbness, hyperglycemia, proteinuria, xanthopsia, enuresis, decrease in pulse rate, hypotension, jaundice, cholestasis and parenchymal liver damage and a transient rise in cephalin flocculation and AST.
Hypersensitivity reactions include: fever, facial flush, chills, conjunctival injection, angioneurotic edema, anaphylaxis, lymphadenopathy, erythema multiforme including Stevens-Johnson syndrome, perianal rash and skin rash.
Appearance of live Ascaris in the mouth and nose has been reported on rare occasions.
Some patients may excrete a metabolite which imparts an odor to urine. This is much like that which occurs after ingestion of asparagus and is noted during therapy and for about 24 hours after completion of therapy.
Crystalluria with or without hematuria has been reported on occasion as having occurred during treatment with thiabendazole. The crystalluria promptly subsides with discontinuation of therapy.
Transient leukopenia has been reported in a few patients while receiving thiabendazole therapy. The cause and effect relationship in these cases has not been established.
Symptoms And Treatment Of Overdose: Symptoms and Treatment: No specific antidote. Induce emesis or perform gastric lavage. Treatment is symptomatic and supportive.
Dosage And Administration: Thiabendazole should be given with meals, where possible and should be chewed before swallowing. Dietary restriction, complementary medications and cleansing enemas are not needed.
The usual dosage schedule for all conditions is 2 doses/day. The size of the dose is determined by the patient’s weight. Patients weighing less than 60 kg – 25 mg/kg/dose. Patients weighing 60 kg and over – 1.5 g/dose. The maximum daily dose for adults weighing more than 60 kg is 3 g.
SuppliedSupplied: Each orange (peach) colored, 1.90 cm in diameter, beveled edge, compressed chewable tablet, scored on one side with MSD 907 engraved on the other, contains: thiabendazole 500 mg. Units of 6.
MINTEZOL® MSD Thiabendazole Anthelmintic