ANTI HELMINTHES DRUGS GET DEEP UNDERSTANDING

Anti Helminthes Drugs

STEP 2:Anti Helminthes

Antihelminthes drugs include; Mebendazole, Albendazole, Ivermectin, Niclosamides and Thiabendazoles. Others include Piperazine and Praziquental.

The indications of different essential antihelminthes are : 

Mebendazole is effective in treatment of the following parasitic infestations: Roundworm ,Thread worms ,Whipworm, Hook worms .

Albendazole are effective treatment of following parasites: Hookworms, Roundworms, Tapeworms ,Strongyloides ,Cutaneous lava migrains.

Ivermectin are effective for treatment of: Filariasis Cutaneous larva migrans.

Niclosamides are effective for treatment of tapeworms.

Thiabendazoles are used in treatment stronyloides .

Indications of other antihelminthes not in the National Essential Medicine List(NEMLIT) are: Piperazine is effective for threadworms and round worms.

Praziquental is used in treatment of schistosomiasis.

STEP 3: Contraindication of Antihelminthes.

The contraindication of the essential antihelminthes drugs are:

Pregnancy during first trimester (Mebendazole, albendazole, thiabendazoles).

Known hypersensitivity to antihelminthes drugs.

STEP 4: Dose, Dosage and Course of Antihelminthes.

Mebendazole Adult and Children above 2 years 100mg 12 hourly for 3 days Or 500mg as a single dose 

Albendazole 400mg as a single dose. 

Levamisole Adult 120-150 mg as a single dose.

Children below 2 years 3 mg/kg body weight as single dose Or 2.5 mg/kg body weight as single dose, repeated after 7 days.

Niclosamide Adult: 2g as a single dose. Chew tablets on an empty stomach Children: 30mg/kg body weight starts on an empty stomach For Taenia solium, Taenia saginata and Diphyllobothrium latum .

Adults and children over 6 years: 2g as a single dose after a light breakfast, followed by a purgative after 2 hours Children 2-6 years: 1g as a single dose after a light meal, followed bya purgative after 2 hours 

Children under 2 years 500mg as a single dose after a light meal, followedby a purgative after 2 hours .

For Hymenolepsis nana Adult and children over 6 years 2g as a single dose on the first day, then 1g daily for 6 days

Children under 2 years 500mg on the first day as a single dose then 250mg daily for 6 days.

Children 2-6 years 1g on the first day as a single dose then 500mg once daily. 

Ivermectin 150mcg/kg (0.15mg/kg) body weight as a single dose .

Treat again at intervals of 6 to 12 months, depending on symptoms or until the adult worms die out .

Diethylcarbamazine (DEC) 1mg/kg body weight.  Increase the dose gradually by 1mg/kgbody at an interval of 3 days to maximum of 6mg/kg body weight.  Duration of treatment is 21 days 

Thiabendazole Adults: 25mg/kg body weight (max.1.5g) 12 hourly for 3 days Tablets must be chewed Children Same as for adults

STEP 5: Side Effects and Adverse Effects of Antihelminthes:

Mebendazole Side effects and adverse effects: 

Very rarely abdominal pain, diarrhoea, convulsions (in infants) 

Rash (including Stevens-Johnson syndrome and toxic epidermal necrolysis) 

Short-term mebendazole therapy for intestinal nematodes is nearly free of adverse effects

Mild nausea, vomiting, diarrhoea, and abdominal pain have been reported infrequently.

Rare side effects, usually with high-dose therapy, are hypersensitivity reactions (rash, urticaria), agranulocytosis, alopecia, and elevation of liver enzymes 

Niclosamide side-effects and adverse effects:

Occasional gastro-intestinal upset ,Lightheadedness, Pruritis ,Infrequent, mild, and transitory adverse events include nausea, vomiting, diarrhea, and abdominal discomfort .

Ivermectin Side-effects and adverse effects: In strongyloidiasis treatment infrequent side effects includes: Fatigue, dizziness, nausea, vomiting, abdominal pain, and rashes. In onchocerciasis treatment,the adverse effects are principally from the Mazotti reaction, due to killing of microfilariae 

Albendazole Side-effects and adverse effects: 

When used for 1-3 days, albendazole is nearly free of significant adverse effects. 

Mild and transient epigastric distress, diarrhea, headache, nausea, dizziness, lassitude, and insomnia can occur In long-term use for hydatid disease, albendazole is well tolerated, but it can cause abdominal distress, headaches, fever, fatigue, alopecia, increases in liver enzymes, and pancytopenia.

Blood counts and liver function studies should be followed during long-term therapy.

Thiabendazole Side effects and adverse effects include:

Dizziness, anorexia, nausea, and vomiting. 

Less frequent problems are epigastric pain, abdominal cramps, diarrhea, pruritus, headache, drowsiness, and neuropsychiatric symptoms.  Irreversible liver failure and fatal Stevens-Johnson syndrome have been reported.

 STEP 6: Interaction and Precaution of Essential Antihelminthes.

Mebendazole

Interaction Serum levels of mebendazole may be decreased by concomitant use of carbamazepine or phenytoin and increased by cimetidine.

Precaution Mebendazole should be used with caution in patients with cirrhosis 

Mebendazole is teratogenic in animals and therefore contraindicated in pregnancy.

It should be used with caution in children younger than 2 years of age because of limited experience and rare reports of convulsions in this age group 

Albendazole Precaution:

The drug should not be given to patients with known hypersensitivity to other benzimidazole drugs .

The drug should not be given to patients with cirrhosis. 

The safety of albendazole in pregnancy and in children younger than 2 years of age has not been established .

Thiabendazole Precaution:

Much more toxic than other benzimidazole or Ivermectin, so other agents are now preferred for most indications.

Experience with thiabendazole is limited in children weighing less than 15 kg. The drug should not be used in pregnancy or in the presence of hepatic or renal disease.

 Niclosamide Precaution:

 The consumption of alcohol should be avoided on the day of treatment and for 1 day afterward.

The safety of the drug has not been established in pregnancy or for children younger than 2 years of age.

Ivermectin Interaction;

It is best to avoid concomitant use of Ivermectin and other drugs that enhance GABA activity for example Barbiturates ,Benzodiazepines ,Valproic acid 

Precaution:

Ivermectin should not be used in pregnancy.

Safety in children younger than 5 years has not been established 

Step 7: Key Points:

The essential antihelminthes for treatment of parasitic infestation are: Mebendazole, Albendazole, thiabendazole, Niclosamide and Ivermectin. 

Most of antihelminthes are contraindicated in pregnancy especially during first trimester.

Most of antihelminthes are taken orally Common side effects are nausea, vomiting and diarrhoea.

Antihelminthes interact with other drugs. Antihelminthes should be used with caution in person with liver problems

 

STEP 8: References

 Ministry of Health and Social Welfare. (2013).

 Standard Treatment Guidelines & National Essential Medicines List Tanzania Mainland (4th ed.). Dar es salaam, Tanzania government printers.

Robert L. Talbert, Gary C. Yee, Gary R. Matzke, Barbara G. Wells, L. Michael. (2014). Pharmacotherapy: Aa Ppathophysiologic Aapproach (9th ed.). 

New York, McGraw-Hill Education. Sally S.R, Jeanne C.S. (2000). Introductory Clinical Pharmacology (6th ed) New York, Lippincott Williams and Wilkins.

School of Pharmaceutical sciences. (2011).Tanzania Pharmaceutical Handbook (2nd ed.). Dar es Salaam, ARDHI University press.

The Royal Pharmaceutical Society of Great Britain. (2007).

Martindale, The Extra Pharmacopoeia (5TH ed). London, Pharmaceutical press.

The Royal Pharmaceutical Society of Great Britain. (2009).

 British National Formulary (59th ed). London, BMJ Group and RPS.

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