Piperazine was originally introduced into medicine as a solvent for uric acid. When taken into the body the drug is partly oxidized and partly eliminated unchanged. Outside the body, piperazine has a remarkable power to dissolve uric acid and producing a soluble urate, but in clinical experience it has not proved equally successful. Lycetol, lysidine and sidonal are compounds having similar action. Many piperazine derivatives are notable successful drugs, including:

Piperazine citrate (antiparasitic)
Viagra (impotence drug)
Levitra (impotence drug)
Imatinib (leukemia drug)
Meclizine (motion sickness drug)
Cyclizine (antiemetic antihistamine)
Niaprazine (sedating antihistamine)
Trazodone (sedating antidepressant)
Nefazodone (analgesic antidepressant)
Antrafenine (analgesic)
Befuraline (stimulant antidepressant)
Trelibet (stimulant antidepressant)
Fipexide (nootropic)
Trimetazidine (anti-angina drug)
Ranolazine (anti-angina drug)
BZP (recreational stimulant)
TFMPP (recreational hallucinogen)
mCPP (recreational stimulant)
MeOPP (recreational stimulant)
pFPP (recreational hallucinogen)

Piperazine was first introduced as an anthelmintic in 1953. A large number of piperazine compounds have anthelmintic action. Their mode of action is generally by paralysing parasites, which allows the host body to easily remove or expel the invading organism. This action is mediated by its agonist effects upon the inhibitory GABA (γ-aminobutyric acid) receptor. Its selectivity for helminths is because vertebrates only use GABA in the CNS and the helminths' GABA receptor is a different isoform to the vertebrate's one. Piperazine hydrate and piperazine citrate are the main anthelminthic piperazines. These drugs are often referred to simply as "piperazine" which may cause confusion between the specific anthelmintic drugs and the entire class of piperazine-containing compounds.