For prevention and treatment of nausea, vomiting, and dizziness associated with motion sickness and vertigo (dizziness caused by other medical problems).
Buclizine is a piperazine-derivative antihistamine used as an antivertigo/antiemetic agent. Buclizine is used in the prevention and treatment of nausea, vomiting, and dizziness associated with motion sickness. Additionally, it has been used in the management of vertigo in diseases affecting the vestibular apparatus. Although the mechanism by which buclizine exerts its antiemetic and antivertigo effects has not been fully elucidated, its central anticholinergic properties are partially responsible. The drug depresses labyrinth excitability and vestibular stimulation, and it may affect the medullary chemoreceptor trigger zone. It also possesses anticholinergic, antihistaminic, central nervous system depressant, and local anesthetic effects.
Mechanism of action
Vomiting (emesis) is essentially a protective mechanism for removing irritant or otherwise harmful substances from the upper GI tract. Emesis or vomiting is controlled by the vomiting centre in the medulla region of the brain, an important part of which is the chemotrigger zone (CTZ). The vomiting centre possesses neurons which are rich in muscarinic cholinergic and histamine containing synapses. These types of neurons are especially involved in transmission from the vestibular apparatus to the vomiting centre. Motion sickness principally involves overstimulation of these pathways due to various sensory stimuli. Hence the action of buclizine which acts to block the histamine receptors in the vomiting centre and thus reduce activity along these pathways. Furthermore since buclizine possesses anti-cholinergic properties as well, the muscarinic receptors are similarly blocked.
This compound belongs to the class of chemical entities known as diphenylmethanes. These are compounds containing a diphenylmethane moiety, which consists of a methane wherein two hydrogen atoms are replaced by two phenyl groups.
In peripheral tissues, the H1 subclass of histamine receptors mediates the contraction of smooth muscles, increase in capillary permeability due to contraction of terminal venules, and catecholamine release from adrenal medulla, as well as mediating neurotransmission in the central nervous system.
The muscarinic acetylcholine receptor mediates various cellular responses, including inhibition of adenylate cyclase, breakdown of phosphoinositides and modulation of potassium channels through the action of G proteins. Primary transducing effect is Pi turnover.