Thenalidine is an antihistamine with anticholinergic properties used as an antipruritic drug. It was withdrawn from the US, Canadian, and UK markets due to a risk of neutropenia. Thenalidine is an antagonist of the H1-receptor.

Phenmetrazine is an anti-obesity drug, which was discovered by Boehringer-Ingelheim in 1952 and approved by FDA under the name Preludin. Later on the drug was withdrawn from the market due to the reported cases of abuse. According to some studies, misuse of phenmetrazine turned many young addicts to crime. It is suggested that the drug exerts its effect by inhibiting the monoamine transport.

Pyrvinium (Viprynium) is an anthelmintic effective for pinworms. Pyrvinium is used in the treatment of enterobiasis caused by Enterobius vermicularis (pinworm). Pyrvinium has being shown to be a potent inhibitor of Wnt signaling (EC(50) of ∼10 nM). Pyrvinium binds all casein kinase 1 (CK1) family members in vitro at low nanomolar concentrations and pyrvinium selectively potentiates casein kinase 1α (CK1α) kinase activity. Pyrvinium pamoate (PP) is a potent noncompetitive inhibitor of the androgen receptor (AR). A noncompetitive AR inhibitor pyrvinium has significant potential to treat CRPC, including cancers driven by ligand-independent AR signaling.

Pentoxyverine is a non-opioid antitussive used to prevent cough caused by common cold. It is used as an active ingredient of several oral over-the-counter cough suppressants alone or in combination with other medications, especially decongestants. Certuss is a combination of pentoxyverine and guaifenesin. Pentoxyverine is FDA pregnancy category C drug. Known as anticonvulsant, and spasmolytic agent.

Procyclidine is a muscarinic antagonist that crosses the blood-brain. Procyclidine hydrochloride (brand name Kemadrin) is a synthetic antispasmodic compound of relatively low toxicity. It has been shown to be useful for the symptomatic treatment of parkinsonism (paralysis agitans) and extrapyramidal dysfunction caused by tranquilizer therapy. Procyclidine hydrochloride was developed at The Wellcome Research Laboratories as the most promising of a series of antiparkinsonism compounds produced by chemical modification of antihistamines. Kemadrin is indicated in the treatment of parkinsonism including the postencephalitic, arteriosclerotic, and idiopathic types. Partial control of the parkinsonism symptoms is the usual therapeutic accomplishment. Procyclidine hydrochloride is usually more efficacious in the relief of rigidity than tremor; but tremor, fatigue, weakness, and sluggishness are frequently beneficially influenced. It can be substituted for all the previous medications in mild and moderate cases. For the control of more severe cases, other drugs may be added to procyclidine therapy as indications warrant. The mechanism of action is unknown. It is thought that procyclidine acts by blocking central cholinergic receptors, and thus balancing cholinergic and dopaminergic activity in the basal ganglia. Pharmacologic tests have shown that procyclidine hydrochloride has an atropine-like action and exerts an antispasmodic effect on smooth muscle. It is a potent mydriatic and inhibits salivation. It has no sympathetic ganglionblocking activity in doses as high as 4 mg/kg, as measured by the lack of inhibition of the response of the nictitating membrane to preganglionic electrical stimulation.

Pentoxyverine is a non-opioid antitussive used to prevent cough caused by common cold. It is used as an active ingredient of several oral over-the-counter cough suppressants alone or in combination with other medications, especially decongestants. Certuss is a combination of pentoxyverine and guaifenesin. Pentoxyverine is FDA pregnancy category C drug. Known as anticonvulsant, and spasmolytic agent.

Pyrvinium (Viprynium) is an anthelmintic effective for pinworms. Pyrvinium is used in the treatment of enterobiasis caused by Enterobius vermicularis (pinworm). Pyrvinium has being shown to be a potent inhibitor of Wnt signaling (EC(50) of ∼10 nM). Pyrvinium binds all casein kinase 1 (CK1) family members in vitro at low nanomolar concentrations and pyrvinium selectively potentiates casein kinase 1α (CK1α) kinase activity. Pyrvinium pamoate (PP) is a potent noncompetitive inhibitor of the androgen receptor (AR). A noncompetitive AR inhibitor pyrvinium has significant potential to treat CRPC, including cancers driven by ligand-independent AR signaling.

Pyrvinium (Viprynium) is an anthelmintic effective for pinworms. Pyrvinium is used in the treatment of enterobiasis caused by Enterobius vermicularis (pinworm). Pyrvinium has being shown to be a potent inhibitor of Wnt signaling (EC(50) of ∼10 nM). Pyrvinium binds all casein kinase 1 (CK1) family members in vitro at low nanomolar concentrations and pyrvinium selectively potentiates casein kinase 1α (CK1α) kinase activity. Pyrvinium pamoate (PP) is a potent noncompetitive inhibitor of the androgen receptor (AR). A noncompetitive AR inhibitor pyrvinium has significant potential to treat CRPC, including cancers driven by ligand-independent AR signaling.

Pyrvinium (Viprynium) is an anthelmintic effective for pinworms. Pyrvinium is used in the treatment of enterobiasis caused by Enterobius vermicularis (pinworm). Pyrvinium has being shown to be a potent inhibitor of Wnt signaling (EC(50) of ∼10 nM). Pyrvinium binds all casein kinase 1 (CK1) family members in vitro at low nanomolar concentrations and pyrvinium selectively potentiates casein kinase 1α (CK1α) kinase activity. Pyrvinium pamoate (PP) is a potent noncompetitive inhibitor of the androgen receptor (AR). A noncompetitive AR inhibitor pyrvinium has significant potential to treat CRPC, including cancers driven by ligand-independent AR signaling.

Buclizine, a piperazine derivative, is a sedating antihistamine with antimuscarinic and moderate sedative action. The drug is used mainly for its antiemetic action, particularly in the prevention of motion sickness, and in the treatment of migraine in combination with analgesics. The following side/adverse effects have been selected on the basis of their potential clinical significance: drowsiness; Incidence less frequent; blurred vision; dryness of mouth, nose, and throat; headache; nervousness, restlessness, or trouble in sleeping; upset stomach. The following drug interactions have been selected on the basis of their potential clinical significance: alcohol; anticholinergics or other medications with anticholinergic activity; apomorphine.