CLASS ANTIAMOEBIC

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ANTIAMOEBIC DRUGS: 

ANTIAMOEBIC DRUGS Dr. RAGHU PRASADA M S MBBS,MD ASSISTANT PROFESSOR DEPT. OF PHARMACOLOGY SSIMS & RC. 1

CLASSIFICATION: 

CLASSIFICATION TISSUE AMOEBICIDES INTESTINAL AND EXTRA INTESTINAL AMOEBICIDES METRONIDAZOLE, TINIDAZOLE, ORNIDAZOLE, SECNIDAZOLE, NIMORAZOLE, EMETINE, DIHYDROEMETINE EXTRA INTESTINAL AMOEBICIDES CHLOROQUINE

LUMINAL(INTESTINAL) AMOEBICIDES: 

LUMINAL(INTESTINAL) AMOEBICIDES AMIDES-DILOXANIDE FUROATE 8-HYDROXYQUINOLINES-DIIODOHYDROXYQUIN(IODOQUINOL) ANTIBIOTICS- TETRACYCLINES, PAROMOMYCIN

AMOEBICIDES: 

AMOEBICIDES

METRONIDAZOLE: 

METRONIDAZOLE It is protype nitroimidazole , highly active amoebicide . selectivity of nitro group containing antibacterial, antiamoebic , antitrypanosomal arises from absence of nitroreudctase in human and presence of it in the invading organism. 2) so we can say that in metronidazole , tinidazole , secnidazole , nitro group cause both the activity and selectivity. It has broad spectrum cidal activity against protozoa, including Giardia lamblia .

Mechanism of Action: 

Mechanism of Action Metronidazole is selectively toxic to anaerobic microorganisms. It enters the cell by diffusion then its nitro group is reduced by redox protiens to highly reactive nitro radical which exerts cytotoxicity by damaging DNA & other critical biomolecules .

Pharmacokinetics: 

Pharmacokinetics Completely absorbed from intestine. Widely distributed in the body. Metabolized in liver & excreted in urine. Plasma t1/2 is 8 hrs.

Adverse Effects: 

Adverse Effects Anorexia Nausea Metallic taste Abdominal cramps Loose stool is occasional Headache Dryness of mouth

Contraindications: 

Contraindications Neurological disorder Blood dyscrasias Ist trimester of pregnancy Chronic alcoholism

Interactions: 

Interactions A disulfiram like intolerance to alcohol occurs; patients should avoid drinking. When metronidazole is given with alcohol abdominal distress, nausea, vomiting, flushing, or headache, tachycardia, hyperventilation aldehyde dehydrogenase Ethanol  Acetaldehyde  Acetate Enzyme inducer( phenobarbitone,rifampicin ) Cimetidine reduce metabolism. It decrease renal metabolism of lithium.

Uses: 

Uses Amoebiasis Giardiasis Trichomonas vaginitis Anaerobic bacterial infections Pseudomembranous enterocolitis

ALKALOIDS- EMETINE, DEHYDROEMETINE: 

ALKALOIDS- EMETINE, DEHYDROEMETINE It is potent & directly acting amoebicide Mechanism  Act on tissue trophozoites causing irreversible block of protein synthesis. Metabolized & Excreted slowly via kidney so it has a cumulative effect. It is not given orally as it is vomited out. Dehydroemetine is less toxic than emetine cardiotoxicity

CHLOROQUINE: 

CHLOROQUINE It is used for extraintestinal amoebiasis only. It kills trophozoites of E.histolytica . & highly conc.in liver. Antimalarial drug Used in combination with metronidazole as luminal amoebicide for amoebic liver diseases.

DILOXANIDE FUROATE: 

DILOXANIDE FUROATE It is highly effective luminal amoebicide . Drug of choice for mild intestinal/asymptomatic amoebiasis . Less effective in invasive dysentery. Given orally  Split in the intestine, most of diloxanide is absorbed, conjugated to form a glucoronide which is excreted in urine (90%). The unabsorbed diloxanide is the amoebicidal agent (10%). Well tolerated Side Effects are flatulence, nausea, urticaria .

8-HYDROXYQUINOLINES-Iodoquinol : 

8-HYDROXYQUINOLINES-Iodoquinol It kill the cyst forming trophozoites in the intestine. These are used for prophylaxis & treatment of nonspecific diarrhoeas , travellers diarrhoea , dietary indisecretion . Its side effects are few-nausea, transient loose & green stool Goitre occurs on prolonged use. Iodism occur due to chronic iodine overload. Repeated use of high doses causes a neuropathic syndrome called ‘ subacute myelo -optic neuropathy’.

DRUGS FOR GIARDIASIS: 

DRUGS FOR GIARDIASIS Giardia lamblia lives as commensal in the intestine. It sometimes invades the mucosa & causes diarhoea . TREATMENT: Metronidazole - 200 mg TDS for 7days Mepacrine - 100 mg TDS for 5days Quinidochlor - 250 mg TDS for 7 days. Furazolidone -100 mg TDS for 5-7 days.

DRUGS FOR TRICHOMONIAISIS : 

DRUGS FOR TRICHOMONIAISIS Trichomonas vaginalis is a protozoon causing vulvovaginitis . TREATMENT: Drugs used orally; Metronidazole 400 mg TDS for 7 days Nimorazole 2 g single dose with meals Drugs used intravaginally ; Diiodohydroxyquin 200 mg Quiniodochlor 200 mg Clotrimoxazole 100 mg

DRUGS FOR TRIPANOSOMIASIS: 

DRUGS FOR TRIPANOSOMIASIS AFRICAN TRIPANOSOMIASIS-T.BRUCEI SURAMIN, PENTAMIDINE, MELARSOPROL, EFLORNITHINE AMERICAN TRIPANOSOMIASIS-T.CRUZI NIFURTIMOX BENZNIDAZOLE

DRUGS FOR LEISHMANIASIS: 

DRUGS FOR LEISHMANIASIS Leishmania donovani causes visceral leishmaniasis ( kala-azar ). It occur in subtropical regions of world. It is transmitted by bite of female sandfly phlebotomus .

LEISHMANIASIS DRUGS: 

LEISHMANIASIS DRUGS ANTIMONIALS Sodium stibogluconate Meglumine antimonate DIAMIDINE Pentamidine OTHERS Amphotericin B, Ketoconazole Miltefosine , Allopurinol

ANTIMONIALS: 

ANTIMONIALS SODIUM STIBOGLUCONATE: It is drug of choice for kala-azar . Mechanism of action is inhibition of –SH dependent enzymes & blockage of glycolytic & fatty acid oxidation pathways. Adverse effects are nausea, vomiting Metallic taste, cough, abdominal pain etc. Pancreatitis,liver & kidney damage, myelosuppression , ECG changes are possible. Few cases of shock.

DIAMIDINE-Pentamidine: 

DIAMIDINE- Pentamidine It interacts with kinetoplast DNA & inhibits topoisomerase II or interfere with aerobic glycolysis . Toxicity is high-acute reaction: sharp fall in BP, cardiovascular collapse, dyspnoea , Liver & kidney damage, mental confusion, ECG changes, arrythmias . It causes cytolysis of pancreatic b cells. USES: Kala- azar Pneumocystis carinii Trypanosomiasis

Pentamidine: 

Pentamidine Liver & kidney damage, mental confusion, ECG changes, arrythmias . It causes cytolysis of pancreatic b cells. USES: Kala- azar Pneumocystis carinii Trypanosomiasis

Suramin: 

Suramin Used in the early treatment and prophylaxis of African trypanosomiasis . It acts by inhibiting enzymes of energy metabolism including glycerol phosphate dehydrogenase – for trypanocidal activity

Melarsoprol: 

Melarsoprol Trivalent arsenical Mainly used to treat trypanosoma infections with CNS involvement. The drug acts by reacting with SH groups of various enzymes

Nifurtimox -Chagas disease : 

Nifurtimox - Chagas disease Used in the treatment of Trypanosoma cruzi infection. It acts by generating superoxide and hydrogen peroxide radicals – toxic as they lack catalase . Orally well absorbed Thank you