33 Anthelminthic drugs Flashcards
33.01 ANTHELMINTHIC DRUGS
Mebendazole (similar: tiabendazole, albendazole) - actions
anthelminthic agent
33.01 ANTHELMINTHIC DRUGS
Mebendazole (similar: tiabendazole, albendazole) - MOA
inhibits microtubule synthesis, impairing microtubule functions such as glucose uptake
33.01 ANTHELMINTHIC DRUGS
Mebendazole (similar: tiabendazole, albendazole) - abs/distrib/elim
given orally
poor uptake is improved by fatty foods
33.01 ANTHELMINTHIC DRUGS
Mebendazole (similar: tiabendazole, albendazole) - clinical use
thread worm, round worm, whip worm and hookworm infections
albendazole also used for cutaneous larva migrans, cysticercosis, strongyloidiases
33.01 ANTHELMINTHIC DRUGS
Mebendazole (similar: tiabendazole, albendazole) - adverse effects
GIT disturbances, rash
rarely convulsions in infants
33.01 ANTHELMINTHIC DRUGS
Mebendazole (similar: tiabendazole, albendazole) - special points
mebendazole is considered unsuitable for pregnant women or children <2 years old
33.02 ANTHELMINTHIC DRUGS
Levamisole - actions
a narrow-spectrum anthelminthic agent
33.02 ANTHELMINTHIC DRUGS
Levamisole - MOA
causes tonic paralysis of the worm by stimulating nicotinic receptors at the neuromuscular junction
the paralysed worms (but not the ova) are expelled in the faeces
33.02 ANTHELMINTHIC DRUGS
Levamisole - abs/distrib/elim
given orally
plasma half-life 4h
33.02 ANTHELMINTHIC DRUGS
Levamisole - clinical use
common round worm infection
33.02 ANTHELMINTHIC DRUGS
Levamisole - adverse effects
mild GIT disturbances
33.02 ANTHELMINTHIC DRUGS
Levamisole - special points
drug has been withdrawn from North American market
33.03 ANTHELMINTHIC DRUGS
Piperazine - actions
a narrow-spectrum anthelminthic agent
33.03 ANTHELMINTHIC DRUGS
Piperazine - MOA
reverses neuromuscular transmission in the worm
the paralysed worms are expelled alive in the faeces
33.03 ANTHELMINTHIC DRUGS
Piperazine - abs/distrib/elim
given orally
33.03 ANTHELMINTHIC DRUGS
Piperazine - clinical use
common round worm infection
33.03 ANTHELMINTHIC DRUGS
Piperazine - adverse effects
GIT disturbances
rash, bronchospasm
some patients experience CNS symptoms, e.g. dizziness, paraesthesias
33.03 ANTHELMINTHIC DRUGS
Piperazine - special points
discontinued in United Kingdom
not suitable for pregnant women or for patients with impaired renal or hepatic function
33.04 ANTHELMINTHIC DRUGS
Praziquantel - actions
a broad-spectrum anthelminthic agent
33.04 ANTHELMINTHIC DRUGS
Praziquantel - MOA
increases the calcium permeability of the cell membranes, promoting calcium influx, resulting in prolonged contraction of muscle with eventual paralysis and death
33.04 ANTHELMINTHIC DRUGS
Praziquantel - abs/distrib/elim
given orally, well absorbed, metabolised to inactive products
plasma half-life 60-90min
33.04 ANTHELMINTHIC DRUGS
Praziquantel - clinical use
schistosomiasis, cysticercosis
33.04 ANTHELMINTHIC DRUGS
Praziquantel - adverse effects
few and minor: sometimes GIT disturbances
33.04 ANTHELMINTHIC DRUGS
Praziquantel - special points
considered safe for pregnant and lactating women
33.05 ANTHELMINTHIC DRUGS
Ivermectin - actions
a broad-spectrum anthelminthic agent
33.05 ANTHELMINTHIC DRUGS
Ivermectin - MOA
acts at the worm’s neuromuscular junction, causing paralysis either by intensifying GABA-mediated inhibition or by activating an invertebrate-specific glutamate-gated chloride channel
33.05 ANTHELMINTHIC DRUGS
Ivermectin - abs/distrib/elim
given orally
half-life 11h
33.05 ANTHELMINTHIC DRUGS
Ivermectin - clinical use
onchocerciasis (drug of choice)
strongyloidiasis
filarial infections
active against some roundworm, but not hookworms
33.05 ANTHELMINTHIC DRUGS
Ivermectin - adverse effects
infrequent: itching, rash, GIT disturbances, dizziness, fatigue
33.06 ANTHELMINTHIC DRUGS
Diethylcarbamazine - actions
anthelminthic drug - piperazine derivative
33.06 ANTHELMINTHIC DRUGS
Diethylcarbamazine - MOA
removes microfilariae from the blood circulation and has limited effect on the adult worms in the lymphatics
may act by changing the parasite, making it susceptible to the host’s normal immune responses or by interfering with helminth arachidonate metabolism
33.06 ANTHELMINTHIC DRUGS
Diethylcarbamazine - abs/distrib/elim
given orally
partly metabolised - parent drug and metabolites excreted in urine and cleared from body within 48h
33.06 ANTHELMINTHIC DRUGS
Diethylcarbamazine - clinical use
filarial infections
33.06 ANTHELMINTHIC DRUGS
Diethylcarbamazine - adverse effects
GI disturbances, joint pain, headache, general feeling of weakness
allergic effects referable to the products of the dying filariae are common and vary with species of worm
33.07 ANTHELMINTHIC DRUGS
Niclosamide - actions
anthelminthic
33.07 ANTHELMINTHIC DRUGS
Niclosamide - MOA
the scolex and a proximal segment of the worm are irreversibly damaged - worm separates from intestinal wall and is expelled
thought to result from uncoupling of phosphorylation or stimulation of ATPase activity
33.07 ANTHELMINTHIC DRUGS
Niclosamide - abs/distrib/elim
given orally
minimal absorption from GI tract
33.07 ANTHELMINTHIC DRUGS
Niclosamide - clinical use
tapeworm infections - used together with praziquantel
33.07 ANTHELMINTHIC DRUGS
Niclosamide - adverse effects
nausea, vomiting, pruritus, light-headedness
