Thiazinamium is an anti-cholinergic phenothiazine deriva¬tive, which also has antihistaminic properties. Intramuscular injection of Thiazinamium induces considerable bronchodilatation, but inconsistent results have been obtained after oral administration. The bioavailability of oral Thiazinamium is only 2-3% of that occurring after intramuscular injection. Intrarectal Thiazinamium is slightly better absorbed (3-9%). The elimination half-life of the parenteral drug is short, being about 20 minutes in most patients. Thiazinamium has been available for the treatment of asthma since the early 1960s but currently withdrawn in most countries. Compared with inhaled ipratropium bromide, intramuscular Thiazinamium and intramuscular atropine were associated with 'extremely frequent side-effects’. Notable tachycardia occurred shortly after intramuscular injection of Thiazinamium in two trials. Dry mouth was reported as ‘frequent’ with oral Thiazinamium, and micturition problems of moderate severity affected 13% of patients.

Talastine (trade name Ahanon), an alkylamine H1-antihistamine, was studied as a reason for an allergic drug exanthema.

TOLPROPAMINE is an alkylamine H1-antihistamine used as an antipruritic and topical antihistaminic.

Antihistamine agent

Quifenadine is an antihistaminic agent. Quifenadine both blocks histamine H1-receptors in the peripheral tissues, and activates enzyme diaminoxidase (histaminase), due to this decreasing the histamine concentration in tissues. It is indicated in cases of pollinosis, acute and chronic urticaria, seasonal rhinitis (hay fever), allergic rhinitis, allergic conjunctivitis, angioneurotic Quinqe’s edema, dermatosis (eczema, neurodermatitis, pruritus etc.), allergic reactions caused by food or medicines. Quifanidine exhibits antiarrhythmic activity in children with frequent premature beats, without significant QT prolongation, or sinus node depression.

Flunarizine is a selective calcium entry blocker with calmodulin binding properties and histamine H1 / dopamine D2 blocking activity. It is not available in the US but marketed in other countries for prophylaxis of a migraine, occlusive peripheral vascular disease, the vertigo of central and peripheral origin, motion sickness and as an adjuvant in the therapy of epilepsy. The drug is also investigated for the treatment of schizophrenia.

Alinastine, a histamine H1 receptor antagonist, that was studied for allergic conjunctivitis, for asthma and for skin disorders, but these experiments were discontinued.

Medibazine (Vialibran) is a piperazine derivative. Medibazine is a coronary vasodilating agent. Although several non-controlled trials report favorable results with angina patients this medication certainly does not provide any outstanding results.

Niperotidine is an H2 antagonist structurally related to ranitidine. H2 antagonists inhibit gastric acid secretion by selectively blocking histamine receptor type 2. Niperotidine was proposed for the treatment of peptic ulcer. Bedtime dose of niperotidine inhibits nocturnal gastric acid secretion in healthy subjects. The duration of niperotidine action was 5 to 7 hours. Twenty-five cases of acute hepatitis (including one death from fulminant hepatitis) associated with niperotidine use were reported in Italy between March and August 1995 and drug was withdrawn from the market. The methylenedioxy group of niperotidine is known to undergo metabolism to catechol and quinone metabolites.

Cyamemazine (Tercian), also known as cyamepromazine, is a typical antipsychotic drug of the phenothiazine class used primarily in the treatment of schizophrenia and psychosis-associated anxiety. Cyamemazine actually behaves like an atypical antipsychotic, due to its potent anxiolytic effects and lack of extrapyramidal side effects. Cyamemazine is used for the treatment of chronic psychotic states, anxiety, major depression.