Praziquantel acts by increasing parasite membrane permeability to calcium, causing paralysis and death; it is particularly effective against which parasites?

• A. Increases parasite membrane permeability to calcium, causing paralysis and death; particularly effective against nematodes
• B. Inhibits glucose uptake in parasites
• C. Blocks neuromuscular transmission by blocking GABA receptors
• D. Increases parasite membrane permeability to calcium, causing paralysis and death; especially effective against cestodes and some trematodes

Answer: (C)

Praziquantel works by increasing parasite membrane permeability to calcium, which causes sustained muscle contraction and paralysis followed by death. This mechanism is especially effective against flatworms, including cestodes (tapeworms) and many trematodes (flukes), because their tegument is particularly susceptible to calcium influx and drug-induced disruption. It is not primarily about inhibiting glucose uptake, nor about blocking GABA receptors—that latter action describes other drugs and does not reflect praziquantel’s work. So the statement pairing calcium permeability with strong activity against cestodes and some trematodes best fits praziquantel’s clinical action.