ANTIHELMINTIC DRUGS

Roundworms

A. LUMBRICOIDES E.

VERMICULARIS ROUNDWORM PINWORM

N. AMERICANUS T. TRICHURAHOOKWORM WHIPWORM

S. STERCORALIS THREADWORM

Tissue Nematodes

ONCHOCERCA Wuchereria bancrofti

ANCYCLOSTOMA

DRUGS THAT ACT AGAINST NEMATODES

A. ALBENDAZOL EMECH OF ACTION – blocks glucose uptake in

both larval and adult parasite , which leads to decrease formation of atp

- inhibition of microtubule assemblyCLINICAL USE : broad anthelintic spectrumfirst drug of choice for larve migrans( ancylostoma spc) alternative drug for roundworms , whipworm,

hookworms,pinworms and threadworm TOXICITY : reversible leukopenia ,

alopecia and changes in the liver anzymes

LONG TERM USE : bone marrow suppresion and fetal toxicity

B. DITHYLCARBAMAZINE MECHANISM OF ACTION : immobilizes

microfilariae CLINICAL USE: drug of choice for filariasisalternative for onchocerciasis ( in

combination with suramin)TOXICITY : headache, malaise, weakness, anorexia

can cause the mazzotti reaction in onchocerciasis – hypotension, pyrexia respiratory distress and prostration fever, rashes and ocular damage

C. IVERMECTINMECHANISM OF ACTION : intesifies gaba

mediated neurotransmission in nematodes resulting to paralysis

CLINICAL USE : drug of choice for onchocerciasis : drug of first choice for strongloidiasis and alternative drug for filariasis

TOXICITY : fever, headache ,dizziness ,rashes, pruritus, tachycardia ,hypotension , joint pains , muscle [ain and pain ion lymph nodes

D. MEBENDAZOLE MECHANISM OF ACTION – selctively inhibit microtubule syntheisi and glucose uptake in nematodes CLINICAL USE :

drug of first choice for pinworms , whipworms and round worms

second drug of choice for cestodes nad trematode infection

TOXICITY : only limited to gastrointestinal irritation . embyrotoxic

E. PIPERAZINE MECH. OF ACTION – acting as agonist at gaba recptors CLINICAL USE ; drug of choice for ascariasis TOXICITY : git irritation

F. PYRANTEL PAMOATE MECH OF ACTION – pyrantel pamoate and its

congener axantel pamoate, stimulate nicotinic receptor present at tne neuromuscular junctions of nematodes. contraction of muscle occurs ,followed by a depolarizarion induced paralysis

CLINICAL USE : ( along with mebendazole) drug of choice for hookworm, pinworm and roundworm infestation .

TOXICITY - git distress ,headache and weakness

TREMATODES

SCHISTOSOMA (BLOOD FLUKE ) LUNG FLUKE

CLONORCHIS SINENSIS(LIVER FLUKE)

DRUGS THAT ACT AGAINST TREMATODES

A. PRAZIQUANTEL MECH. OF ACTION – increases membrane

permeability to calcium, causing marked contraction initially and then paralysis of trematode muscles ; this is followed by vacuolization and parasite death

CLINICAL USE : drug of choice for schistosomiasis, clornorchiasis and paragonimiasis

it is also one of the drug of choice for cestodes

TOXICITY – headache , dizziness, malaise and git irritation , skin rashes and fever

CONTRAINDICATION : ocular cysticercosis

B. BITHIONOL = drug of choice for the treatment of fascioliasis ( sheep liver fluke)

TOXICITY : nausea , vomiting, diarrhea, abdominal cramps, dizziness, dizziness, headache , phototoxicity , pyrxia, tinnitus, proteinuria and leukopenia

C. METRIFONATE – is an organophosphate prodrug that is converted in the body to cholinesterase inhibitor dichlorvos , this active metabolite acts solely against schistosoma haematobium ( the cause of bilharziasis )

D. OXAMNIQUINE – effective solely in schistosoma mansoni infections

TOXICITY : dizziness ,git irritation , pruritusREACTION TO DYING PARASITES –

eosinophilia ,urticaria and pulmonary infiltrates

DRUG THAT ACT AGAIST CESTODES (TAPEWORM)

NICLOSAMIDEMECHANISM OF ACTION ; act by uncoupling

oxidative phosphorylation or by activating atpase

CLINICAL USE : effective in beef, pork and fish tapeworm but not in cysticercosis ( albendazole or prqaziquatel is more effective)

TOXICITY ; git distress ,headache, rash and fever