Betahistine is an orally administered, centrally acting histamine H1 receptor agonist with partial H3 antagonistic activity. It is proposed that betahistine may reduce peripherally the asymmetric functioning of the sensory vestibular organs in addition to increasing vestibulocochlear blood flow by antagonising local H3 heteroreceptors. Betahistine acts centrally by enhancing histamine synthesis within tuberomammillary nuclei of the posterior hypothalamus and histamine release within vestibular nuclei through antagonism of H3 autoreceptors. This mechanism, together with less specific effects of betahistine on alertness regulation through cerebral H1 receptors, should promote and facilitate central vestibular compensation. Betahistine is used to treat the symptoms associated with Ménière's disease, a condition of the inner ear which causes, vertigo (dizziness), tinnitus (ringing in the ears), hearing loss.

Methixene is a tertiary antimuscarinic with actions similar to those of atropine; it also has antihistaminic and direct antispasmodic properties. It is used for the symptomatic treatment of parkinsonism, including the alleviation of the extrapyramidal syndrome induced by other drugs such as phenothiazines, but, like other antimuscarinics, it is of no value against tardive dyskinesias. Metixene has been discontinued. 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 metixene is considered to relate to competitive antagonism of acetylcholine at muscarinic receptors in the corpus striatum, which then restores the balance.

Syrosingopine, a drug derived from reserpine, which was investigated for the treatment of essential hypertension. The combination of syrosingopine and a mitochondrial inhibitor for the treatment of cancer and for achieving immunosuppression was patented. This invention also relates to a fluorescence-based method for predicting syrosingopine sensitivity of a cancer cell.

Antazoline is an antagonist of histamine H1 receptors. It selectively bind to but does not activate histamine H1 receptors, thereby blocking the actions of endogenous histamine, which subsequently leads to temporary relief of the negative symptoms brought on by histamine. Antazoline in combination with naphazoline (VASOCON-A®) is indicated to relieve the symptoms of allergic conjunctivitis.

Linoleic acid is a naturally occurring omega-6 essential fatty acid, present in a variety of foods, including the oils. Linoleic acid is a precursor for arachidonic acid biosynthesis; on the first enzymatic step of the pathway involves delta-6-desaturase, which converts linoleic acid to gamma-lenolenic acid. Linoleic acid has beneficial effects on human skin and hair. Replacement of saturated fat with linoleic acid is advocated to improve serum lipoprotein profiles and reduce the risk of coronary artery disease. Linoleic acid was tested in clinical trilas as a possible remedy against multiple sclerosis.

Xylazine was developed as an antihypertensive agent. During clinical studies in people xylazine was found to have excessive central nervous system depressant effects and it was subsequently introduced for veterinary use as a sedative, analgesic and relaxant. Xylazine is a potent alpha-2 adrenergic agonist. Xylazine in horses and Cervidae may occasionally cause slight muscle tremors, bradycardia with partial A-V heart block and a reduced respiratory rate. Movement in response to sharp auditory stimuli may be observed.

Pibutidine hydrochloride (IT-066), a novel histamine H2 receptor antagonist has powerful and long lasting antisecretory and antiulcer effects and is a useful antisecretory drug for treatment of peptic ulcer diseases.