Piperazine is an alternative for the treatment of ascariasis, with cure rates over 90% when taken for 2 days, but it is not recom-mended for other helminth infections. Piperazine is available as the hexahydrate and as a variety of salts. It is readily absorbed, and maximum plasma levels are reached in 2–4 hours. Most of the drug is excreted unchanged in the urine in 2–6 hours, and excre-tion is complete within 24 hours.
Piperazine causes paralysis of ascaris by blocking acetylcholine at the myoneural junction; unable to maintain their position in the host, live worms are expelled by normal peristalsis.For ascariasis, the dosage of piperazine (as the hexahydrate) is 75 mg/kg (maximum dose, 3.5 g) orally once daily for 2 days. For heavy infections, treatment should be continued for 3–4 days or repeated after 1 week.
Occasional mild adverse effects include nausea, vomiting, diar-rhea, abdominal pain, dizziness, and headache. Neurotoxicity and allergic reactions are rare. Piperazine compounds should not be given to women during pregnancy, to patients with impaired renal or hepatic function, or to those with a history of epilepsy or chronic neurologic disease.