Anthelmintic [Pharmacology]

Anthelmintic
According to the syllabus based on “PHARMACY COUNCIL OF INDIA”
“I Dedicate this work to all the
Students , Pharmacy Faculty & Family Members
Drx. Shubhanshu R.s. Jaiswal

Helminthiasis also known as Worm Infection, is any macro parasitic disease of humans & other animals in which a Part of the body is infected with parasitic worms, known as Helminths.

1. anthelmintic Shubhanshu R.s. Jaiswal D.Pharm [2019-20] 9511082401

2. According to the syllabus based on “PHARMACY COUNCIL OF INDIA” “I Dedicate this work to all the Students , Pharmacy Faculty & Family Members .” Drx . Shubhanshu R.s. Jaiswal

3. Introduction Helminthiasis also known as Worm Infection , is any macro parasitic disease of humans & other animals in which a Part of the body is infected with parasitic worms , known as Helminths . There are numerous species of these Parasites, which are broadly classified into tapeworms, flukes & roundworms. They often live in the GIT of their hosts , but they may also burrow into other organs, where they induce physiological damage.

4. Helminthiasis is prevalent globally about 1/3 rd of world’s population harbours them, but is more common in developing countries with Poorer personal and Environmental hygiene. Causative organisms harm the host by depriving him of food , causing blood loss , injury to organs, intestinal or lymphatic obstruction and by secreting toxins. Introduction

5. Anthelmintic Anthelmintic are the drugs that either KILL [vermicide] or Expel [vermifuge ] infesting Helminths. 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] & low cost . Development of resistance has not been a problem in the clinical use of Anthelmintic.

6. Classification Of Drugs The most Commonly used ANTHELMINTIC DRUGS are as follows : Mebendazole Albendazole Thiabendazole Pyrantel Pamoate Piperazine Diethyl carbamazine citrate Lvermectin

7. Mebendazole It is a benzimidazole introduced in 1972 . This congener of thiabendazole became very popular because it retained the broad-spectrum anthelmintic activity but not the toxicity of its predecessor. It has produced nearly 100% cure rate/reduction in Egg count in Roundworm,Hookworm [Both Species]. The immobilizing and lethal action of Mebendazole on worms is rather slow : takes 2-3 days to develop.

8. Mechanism of Action The Site Of Action of Mebendazole is the Microtubular Protein ‘  -Tubulin ’ of the Parasite. It binds to  -Tubulin of susceptible worms with H igh Affinity and Inhibits its Polymerization. Intracellular microtubules in the cells of the worm are gradually lost. In addition, it probably blocks glucose uptake in the parasite and depletes it’s glycogen stores .

9. Pharmacokinetics Absorption of Mebendazole From Intestines is minimal ; 75-90% of an oral dose is passed in the Faeces. The fraction absorbed is excreted mainly as inactive metabolites in Urine/Faeces.

10. Adverse Effects Diarrhoea, Nausea & Abdominal Pain have attended it’s use in heavy infestation. Allergic reactions, loss of hair & granulocy–topenia have been reported with high doses. Vomiting, Diarrhea, Headache, Dizziness or Drowsiness may occur.

11. Albendazole It is a subsequently introduced congener of Mebendazole . Retains the Broad-Spectrum activity and excellent tolerability of its predecessor & has the advantage of single dose administration in many infestations. One dose treatment has produced cure rates in ascariasis, hookworm (both species) & enterobiasis which are comparable to 3 day treatment with Mebendazole.

12. MOA Pharmacokinetics The mechanism of action of Albendazole is similar to that of Mebendazole. Absorption of Albendazole after oral administration is significant , but inconsistent . It is enhanced when the drug is taken with fatty meal . The fraction absorbed is converted by first pass metabolism to its sulfoxide metabolite which has potent Anthelmintic action.

13. ADVERSE EFFECTS PHARMACOKINETICS Gastrointestinal side effects, Dizziness. Prolonged use has caused : Headache Fever Alopecia Jaundice and Neutropenia. Albendazole sulfoxide is widely distributed in the body, enters Brain and is excreted in urine with a t½ of 8.5 hours & exert Anthelmintic activity in tissues as well.

14. Thiabendazole It was the first benzimidazole polyanthelminitic introduced in 1961 , which covered practically all species of Nematodes infesting the GIT – Pinworm , Hookworm , Roundworm .

15. MOA Pharmacokinetics It also inhibits development of the Egg of worms & Kill larvae . It has Antiinflammatory action as well. Since Thiabendazole is well absorbed from GIT , systemic adverse effects are common. ADVERSE EFFECTS Nausea, vomiting . Abdominal Pain . Diarrhoea . Impairment of Alertness . Itching .

16. Pyrantel Pamoate It was Introduced in 1969 for Pinworm infestation in Children : use soon extended to Roundworm & Hookworm as well. Efficacy against Ascaris, Enterobius and Ancylostoma is High & comparable to that of Mebendazole.

17. Mechanism Of Action Pyrantel Causes ACTIVATION Of Nicotinic Cholinergic Receptors In The Worms Resulting In Persistent Depolarization  slowly Developing Contracture & Spastic Paralysis . Women's Are Then Expelled.

18. ADVERSE EFFECTS PHARMACOKINETICS Pyrantel Pamoate is remarkably Free of side effects: occasional G.I. symptoms, Headache and Dizziness is reported . Only 10-15% of an Oral Dose of Pyrantel Pamoate is absorbed: This is Partly metabolised and excreted in Urine .

19. Piperazine Introduced in 1950 ,it is a highly active drug against Ascaris and Entrobius : achieves 90-100% cure rates . However, because of the availability at more convenient and better tolerated Albendazole/Mebendazole. It is now considered a second choice drug .

20. Piperazine causes Hyperpolarization of A scaris muscle by a GABA agonistic action . Opening of CL ¯ CHANNELS causes relaxation depresses responsiveness to contractile action of ACh . Flaccid Paralysis occurs and worms are expelled alive. Mechanism Of Action

21. ADVERSE EFFECTS PHARMACOKINETICS Piperazine is safe, but Nausea , Vomiting , Abdominal discomfort and Urticarea may be felt. Dizziness and Excitement occurs at high doses: Toxic doses produce Convulsions , Death is due to Respiratory Failure . A considerable fraction of the Oral Dose of Piperazine is absorbed . It is partly metabolized in liver and excreated in urine .

22. Diethyl Carbamazine Citrate Developed in 1948 . it is the first Drug for Filariasis caused by the Nematodes Wuchereria bancrofti [90% cases] and Brugia malayi .

23. Mechanism Of Action Diethyl Carbamazine Citrate is Microfilaricidal . It has a highly selective effect on microfilariae (MF) . A dose of 2 mg / kg TDS clears Mf of W. B ancrofti and B. M alayi from peripheral Blood in 7days . The most important action of DEC appears to be Alteration of organelle membranes of the Mf promoting cell death .

24. ADVERSE EFFECTS PHARMACOKINETICS Side effects are common but generally not serious. Nausea Loss of appetite Headache Weakness Dizziness are a usual complaints. DEC is absorbed after oral ingestion , distributed all over the body, Metabolized in liver & excreated in urine . Excretion is faster in a acidic urine . Plasma t½ of usual clinical doses is 4-12 hours , depending on urinary pH.

25. Thanking You ! Drx.SHUBHANSHU R.S. JAISWAL E-mail: [email protected] Contact No: 9511082401 Address:Barabanki [22500], U.P, . India . OT Incharge Institute Name: Mayo Institute of Medial Sciences. Description : To do Dressing in Minor OT [Surgery Dept.]. Slideshare I’d Shubhanshu R.S Jaiswal https://www.slideshare.net/DrxShubhanshuRsJaisw