2. Anthelminthic Drugs
May 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.
3. 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
18. 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
19. 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
20. Pharmacokinetics
Benzimidazole carbamate
Administered orally, absorption increased
with a fatty meal
Metabolized in the liver to the active
metabolite albendazole sulfoxide
21. 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
22. 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.
23. 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.
24. 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 .
25. 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.
26. 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 .
27. 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.
28. 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.
29. 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
30. 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.
31. 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.
32. 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
34. 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
35. 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.
36. Adverse Effects
GI disturbance
Neurotoxicity, allergic reactions .
Contraindications
Epilepsy or a history of epilepsy
Impaired liver or kidney functions
Pregnancy
Chronic neurologic disease
37. 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.
38. 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.
39. 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.
40. 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.
41. 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
42. 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
43. 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.
44. 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.
45. Clinical uses
Drug of choice for cutaneous larva migrans &
strongyloidiasis.
Onchocerciasis
It is also used for scabies, lice .
Filariasis.
46. 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.
47. Contraindications & Cautions
Concomitant use with other drugs that enhance
GABA
e.g Barbiturates, bnzodiazepines, valproic acid.
Pregnancy
Meningitis
Children under 5 years of age.
48. 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 , leucopenia
Used with caution in children under 8 years of age.
