Transcript
ANTHELMINTIC DRUGS
Anthelminthic DrugsMay act by causing :
Paralysis of the worm.
Damaging the worm leading to partial digestion or
rejection by immune mechanisms.
Interfere with the metabolism of the worm.
*Worms or larvae live in tissues of host body like muscles,
viscera, meninges, subcutaneous tissues.
Adult filariae live in the lymphatics, connective tissue or mesentery of host and produce live embryos or microfilariae, which goes to blood stream.
They are ingested by mosquitoes or similar insects, they develop to larvae in 2o host and pass to mouth parts of insect and re-injected to humans
Ascaris lumbricoids ( common round worm)
filariasis
Hookworm
Pinworm male ,female
Tapeworm
whipworm
Dircrocoelium dendriticum
Fasiola hepatica
Tricuris tricura
Trichinela spiralis
elephantiasis
Hydateid cyct
cysticercosis
ANTHELMINTIC DRUGSM-mebendazole A-albendazoleN-niclosamideI-ivermectinP-praziquantel A-albendazoleL-levamisole P- pyrental pamoateD-diethylcarbamazine mnemonic:MANIPAL PD
ALBENDAZOLE
Broad spectrum oral anthelmintic
Drug of choice for treatment of hydatid
disease and cysticercosis, it is also used for
the treatment of ascariasis, tricurasis and
strongyloidiasis, pinworm, hookworm
Mechanism Of Action
Inhibits microtubule synthesis by binding to β-tubulin.
Inhibits mitochondrial reductase causing reduced
glucose transport.. Intestinal parasites are immobilized
and die slowly.
Larvicidal in hydatid ,cysticercosis , ascariasis and
hook worm infections.
Ovicidal in ascariasis ,hookworm , trichuriasis
Pharmacokinetics
Benzimidazole carbamate
Administered orally, absorption increased with a fatty meal
Metabolized in the liver to the active metabolite albendazole sulfoxide
Pharmacokinetics
Plasma half life is 8-12 hours
Sulfoxide is mostly protein bound
distributes well to tissues and enters
bile, CSF & hydatid cysts.
Metabolites are excreted in urine
Clinical uses
Used on empty stomach when used against intraluminal parasites but with a fatty meal when used against tissue parasites.
In ascariasis, trichuriasis, hookworm, pin worm infections : children over 2 yrs & adults (single dose 400mg, repeated for 2-3 day in heavy ascaris infection . For 2 wks for pin worm infection
2. Hydatid diseases:
drug of choice for medical therapy& adjunctive to surgical removal or aspiration of cysts.
3. Neurocysticercosis:
Used with corticosteroid to decrease the inflammation caused by dying organism and it also reduces the duration of course for 21 days
4. Other infections: Drug of choice in cutaneous and visceral larva migrans , intestinal capillariasis, giardiasis & taeniasis.
Adverse Effects
In short term(1-3 days): Mild epigastric
pain,diarrhea, nausea, headache & insomnia.
In long term use : For hydatid cyst and cysticercosis : abdominal pain, headache ,fever ,fatigue, alopecia , increased liver enzymes , pancytopenia. Blood counts and liver enzymes should be followed.
Not given during pregnancy, hypersensitive people to benzimidazole drugs & children under 2 years .
MEBENDAZOLE (Vermox)
Synthetic benzimidazole Wide spectrum and low incidence of adverse
effects
Mechanism of action:
Inhibits microtubule synthesis .
It kills hookworm, pin worm, ascaris and trichuris eggs.
Pharmacokinetics
Less than 10% of orally administered drug is absorbed
Absorption increases with fatty meal. Absorbed drug is 90 % protein bound Converted to inactive metabolites . Half- life of 2-6 hours Excreted mostly in urine .
Clinical Uses
It is taken orally before or after meal , tablets
should be chewed before swallowing.
Pinworm , trichuriasis, hookworm &
ascaris infections.
In adults and children over 2 yrs cure rate is
90-100 % except hookworm it is less.
Adverse Effects & Precautions
Short term therapy.Mild GI disturbance.
High dose : hypersensitivity reactions, agranulocytosis , alopecia ,elevation of liver enzymes .
Used with caution under 2yrs of age may cause convulsion. Contraindicated in pregnancy.
Enzyme inducers and inhibitors affect plasma level of the drug.
Thiabendazole Benzimidazole Chelating agent and form stable complexes
with metals including iron, but does not bind with calcium.
Rapidly absorbed Half- life of 1-2 hrs Completely metabolized in liver and 90% is
excreted in urine Can also absorbed through skin
Mechanism Of Action
Similar to other benzimidazoles. It is ovicidal for some parasites
Clinical uses: Should be given after meals .and tablets should be
chewed Strongyloidal infections & cutaneous larva
migrans .Thiabendazole cream is applied topically or drug can be given orally for 2 days.
Adverse Effects & Contraindications
More toxic than other benzamidazoles GI disturbances Pruritus, headache, drowsiness, psychoneurotic
symptoms. Irreversible liver failure. Fatal Stevens –Johnson syndrome Not used in young children , pregnancy, hepatic
and renal diseases.
PYRANTEL PAMOATE Broad spectrum Pharmacokinetics: Poorly absorbed from GIT Half of the drug is excreted unchanged in the feces.Mechanism of action: Result in paralysis of worms. It is a neuromuscular blocking
agent Efficacy Very effective against luminal organisms( mature or immature
forms). Not effective against migratory stages in the tissues or against
ova
Clinical uses
Pin worm given orally with or without food
Ascariasis
Hookworm
Adverse Effects
Infrequent mild transient GI disturbance
Drowsiness, headache, insomnia, rash, fever
Contraindications & Cautions
Should be used with caution in liver dysfunction.
Pregnancy
Children under 2 years of age
PIPERAZINE Only recommended for the treatment of ascariasis
cure rate 90% for 2 days treatment. Readily absorbed orally and excreted mostly
unchanged in urine
MOA: Causes paralysis of ascaris by blocking Ach at myoneural junction, the live worms expelled by normal peristalsis.
Treatment is continued for 3-4 days or repeated after one week in case of heavy infections.
Adverse Effects
GI disturbance Neurotoxicity, allergic reactions .
Contraindications
Epilepsy or a history of epilepsy
Impaired liver or kidney functions
Pregnancy
Chronic neurologic disease
NICLOSAMIDE
Second-line drug for treatment of most tapeworm infections.
Mechanism of action: Adult worm( not ova) is rapidly killed by
inhibition of oxidative phosphorylation .
Pharmacokinetics: Poorly absorbed from gut & excreted in urine.
Clinical Uses
Treatment of most forms of tapeworms.
Not effective against cysticercosis or hydatic
disease.
Given in the morning on empty stomach.
Purgative is necessary to purge all dead segments&
prevent liberation of ova.
Adverse effects & Contraindications
Mild, infrequent and transitory GI disturbance
Alcohol consumption should be avoided
Not indicated in children under 2 yrs of age or in
pregnancy.
DIETHYL CARBAMAZINE
Drug of choice for the treatment of filariasis and tropical eosinophilia.
Pharmacokinetics: Rapidly absorbed from gut Half- life is 2-3 hours The drug should be given after meals It is excreted in urine as unchanged or metabolite. Dosage is reduced in urinary alkalosis and renal
impairment.
Mechanism Of Action
Immobilizes microfilariae and alters their surface
structure, displacing them from tissues & making them
susceptible to destruction by host defense mechanism
It has immunosuppressive effects
Adverse Effects
Fever, malaise, papular rash, headache, GI disturbance, cough. Chest, muscle, joint pain
Leucocytosis Retinal hemorrhage Encephalopathy Lymphangitis and lymphadenopathy. It is not teratogenic C/I: Hypertension, Renal disease patient with
lymphangitis
IVERMECTIN
Drug of choice for treatment of strongyloidiasis
Macrocyclic lactone ring
Given only orally
Rapidly absorbed
Does not cross BBB.
Half- life is 16 hrs
Excretion is mainly in feces.
Mechanism Of Action
Acts on the parasites glutamate-gated Cl- channel
receptors . Chloride influx increased, hyperpolarization
occurs , resulting in paralysis of the worm.
Or
Paralyze nematodes by intensifying GABA- mediated
transmission of signals in peripheral nerves.
Clinical uses
Drug of choice for cutaneous larva migrans &
strongyloidiasis.
Onchocerciasis
It is also used for scabies, lice .
Filariasis.
Adverse Effects
Fatigue, dizziness, GI disturbance
Killing of microfilaria result in a Mazotti
reaction ( fever, headache, dizziness,
somnolence, hypotension, tachycardia,
peripheral edema)
Corneal opacities & other eye lesions.
Contraindications & Cautions
Concomitant use with other drugs that enhance
GABA
e.g Barbiturates, bnzodiazepines, valproic acid.
Pregnancy
Meningitis
Children under 5 years of age.
BITHIONOL
Drug of choice for the treatment of fascioliasis ( sheep liver
fluke)
PK: It is orally administered and excreted in urine.A/E:GI disturbance ( N., V., D., A.)
Dizziness, headache Skin rashes, urticaria, Leucopenia
C/I and precautions: Hepatitis , leucopeniaUsed with caution in children under 8 years of age.
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