Methdilazine is a phenothiazine compound with antihistaminic activity. Methdilazine binds to the histamine H1 receptor. This blocks the action of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine. It is used for the symptomatic relief of hypersensitivity reactions and particularly for the control of pruritic skin disorders.

Propiomazine is a typical antipsychotic, blocking H1 receptors and is primarily indicated in conditions Insomnia. Propiomazine was also used under brand name largon for the relief of restlessness and apprehension, preoperatively or during surgery. In addition largon was used as an adjunct to analgesics for the relief of restlessness and apprehension during labor. But this drug was discontinued.

PROTHIPENDYL is a neuroleptic azaphenothiazine used to treat anxiety and agitation in psychotic syndromes. It also shows strong antihistamine and anti-emetic actions.

Dimetindene (trade name Fenistil; other name dimethindene maleate) is a potent antipruritic antihistamine, characterized by the small size of its effective dose and its rapidity of action. Dimetindene is an antihistamine/anticholinergic that is a selective H1 antagonist. Its effect sets in after 20 to 60 minutes and lasts several hours. Dimetindene drops as well as Dimetindene syrup is particularly indicated in pediatric practice. Dimetindene is indicated as symptomatic treatment of allergic reactions: urticaria, allergies of the upper respiratory tract such as hay fever and perennial rhinitis, food, and drug allergies; pruritus of various origins, except pruritus due to cholestasis; insect bites. Dimetindene is also indicated for pruritus in eruptive skin diseases such as chicken-pox. Dimetindene can be as an adjuvant in eczema and other pruriginous dermatoses of allergic origin.

Clemizole is a drug in clinical development for the treatment of hepatitis C virus (HCV) infection. Clemizole is a novel inhibitor of TRPC5 channels. Clemizole is an H1 antagonist. Clemizole, an antihistamine drug that was once widely used for treatment of allergic disease, was recently discovered to be a potent inhibitor (IC50, 24 nM) of the interaction between an HCV protein (NS4B) and HCV RNA. Although clemizole was widely used during the 1950s and 1960s, this was before contemporary regulatory requirements were established for new drug development, and there is very minimal information about its pharmacokinetics and metabolism.

Biperiden, sold under the brandname Akineton was used as an adjunct in the therapy of all forms of parkinsonism (postencephalitic, arteriosclerotic and idiopathic). Was also useful in the control of extrapyramidal disorders due to central nervous system drugs such as phenothiazines and other groups of psychotropics. Biperiden is a weak peripheral anticholinergic agent. It has, therefore, some antisecretory, antispasmodic and mydriatic effects. In addition, biperiden possesses nicotinolytic activity. Parkinsonism is thought to result from an imbalance between the excitatory (cholinergic) and inhibitory (dopaminergic) systems in the corpus striatum. The mechanism of action of centrally active anticholinergic drugs such as biperiden is considered to relate to competitive antagonism of acetylcholine at cholinergic receptors in the corpus striatum, which then restores the balance. Atropine-like side effects such as dry mouth; blurred vision; drowsiness; euphoria or disorientation; urinary retention; postural hypotension; constipation; agitation; disturbed behavior may been seen. Only limited pharmacokinetic studies of biperiden in humans are available.

Trimeprazine (also known as Alimemazine), a phenothiazine used as antipsychotic drug. This drug is used in Russia under brand name TERALIGEN and has anti-histamine, sedative, and anti-emetic (anti-nausea) effects. Teraligen is used to treat neurosis, depression and anxiety of different origins. It prevents and relieves allergic conditions, which cause pruritus and urticaria by blocking histamine produced by the body during an allergic reaction. Trimeprazine competes with free histamine for binding at HA-receptor sites. This antagonizes the effects of histamine on HA-receptors, leading to a reduction of the negative symptoms brought on by histamine HA-receptor binding. Trimeprazine is not approved for use in humans in the United States. Nevertheless, combination of alimemazine and prednisolone (commonly sold under the brand name Temaril-P) is licensed as an antipruritic and antitussive in dogs.

Chlorphenoxamine is an antihistamine and anticholinergic used as an antipruritic and was formerly used in the sympathomimetic treatment of parkinsonism. Histamine receptor H1 antagonist. Chlorphenoxamine is used to treat Allergic conditions, it is reported as an ingredient of Systral in Germany, Malta, Portugal, Thailand, Turkey.

Valethamate bromide ( sold under many brand names such as Epidosin, Dilaton, Valosin, Valamate, Osdil etc), a quarternary ammonium agent, has been used in augmentation of labor. Valethamate has antimuscarinic action and blocks cholinergic receptors in the ganglia. This action along with the direct action on the smooth muscles of the cervix is thought to help cervical dilatation during labor. Since it is not selective, it exerts anticholinergic side effects such as tachycardia, flushing, cotton mouth and photophobia due to mydriasis. Common side effects are palpitations, increased heart rate, arrhythmia, excessive thirst, reduced bronchial secretions, dry mouth, Photophobia, dry skin, loss of accommodation, slow heart rate, flushing.

Bemegride is a CNS stimulant that is used to induce convulsions in experimental animals. It has also been used as a respiratory stimulant and in the treatment of barbiturate overdose. Bemegride is an antidote for barbiturate poisoning. Bemegride has being shown to have an antagonistic action on the GABAA receptor.