Praziquantel has a particularly dramatic effect on patients with schistosomiasis. Studies of those treated have shown that within six months of receiving a dose of praziquantel, up to 90% of the damage done to internal organs due to schistosomiasis infection can be reversed. History
Praziquantel was developed in the laboratories for parasitological research of Bayer AG and Merck KGaA in Germany (Elberfeld and Darmstadt) in the mid-1970s. Society and culture
Brand names
Biltricide (Bayer) Tablets (for human use)
Cesol (Merck) Tablets
Cestoved (Vedco) both tablets and injectable for veterinary use
Cysticide (Merck) Tablets
Distocide (Shin Poong Pharm. Co., Ltd.) tablet (for human use)
Distoside (Chandra Bhagat Pharma Pvt Ltd) tablet (for human use)
Droncit (Bayer) for veterinary use
Drontal (combination with pyrantel pamoate) (Bayer) for veterinary use
D-Worm (Farnum) for veterinary use; note that D-Worm also makes roundworm medicine containing piperidine which is not effective against tapeworms. Fish Tapes (Thomas Labs) for aquarium use
Interceptor Plus chewable tablets (combination with milbemycin) (Elanco) for veterinary use. Note regular Interceptor only has milbemycin and does not contain praziquantel.
Sensitivity reactions: Urticaria, rash, pruritus and eosinophilia in white blood cell counts
Other locations/body as a whole: Lower back pain, myalgia, arthralgia, fever, sweating, various cardiac arrhythmias, and hypotension

Pregnancy
The WHO states praziquantel is safe during pregnancy. Animal studies have failed to reveal evidence of fetal harm. Praziquantel is effective in reducing schistosomiasis during pregnancy. Another trial found that treatment with praziquantel did not increase the rates of low birthweight, fetal death, or congenital anomalies. Drug interactions
The antibiotic rifampicin decreases plasma concentrations of praziquantel.Carbamazepine and phenytoin are reported to reduce the bioavailability of praziquantel. Chloroquine also reduces its bioavailability.The drug cimetidine heightens praziquantel bioavailability. Mechanism of action
The drugs mode of action is not exactly known at present, but experimental evidence indicates praziquantel increases the permeability of the membranes of schistosome cells towards calcium ions. The drug thereby induces contraction of the parasites muscle, resulting in paralysis in the contracted state. The dying parasites are dislodged from their site of action in the host organism and may enter systemic circulation or may be destroyed by host immune reaction (phagocytosis). Additional mechanisms including focal disintegrations and disturbances of oviposition (laying of eggs) are seen in other types of sensitive parasites. Another hypothesis regarding the mechanism of action is that it interferes with adenosine uptake in worms. This effect may have therapeutical relevance given that the schistosome, as the Taenia and the Echinococcus (other praziquantel-sensitive parasites), is unable to synthesize purines, such as adenosine, de novo. Bayers Animal Health Division website states, "Praziquantel is active against cestodes (tapeworms).