Overview

ATMOZIN 25MG tablets contain the active ingredient cinnarizine, which is a type of medicine called an antihistamine. Cinnarizine is also available without a brand name, ie as the generic medicine. Cinnarizine is used to control travel sickness and the symptoms of inner ear disorders such as Meniere's disease. Vomiting is controlled by an area of the brain called the vomiting centre. The vomiting centre is responsible for causing feelings of sickness (nausea) and for the vomiting reflex. It is activated when it receives nerve messages from the vestibular apparatus in the middle ear.
The vestibular apparatus provides continual feedback to the brain about our body position. When something disturbs the vestibular apparatus, such movement of the head when travelling by boat or car, nerve signals are sent from the vestibular apparatus to the vomiting centre. This can cause sensations such as nausea, dizziness or spinning sensations (vertigo) and the reflex of vomiting.
Cinnarizine works by blocking histamine and muscarinic receptors in the vomiting centre in the brain. This prevents the vomiting centre from receiving nerve messages from the vestibular apparatus. In turn, this prevents disturbances in the middle ear from activating the vomiting centre and causing nausea, vertigo and vomiting.

Indications

• Preventing and treating motion sickness.
• Relieving nausea, vomiting, attacks of dizziness or spinning sensations (vertigo) and sensations of ringing or other noise in the ears (tinnitus) associated with Meniere's disease and other middle ear disorders.

Warnings

This medicine may cause drowsiness. If affected do not drive or operate machinery.

You should not drink alcohol while taking this medicine, as this is likely to make drowsiness worse.

If you are due to have any skin prick tests to diagnose allergies you should stop taking this medicine at least 48 hours before the tests. This is because antihistamines can prevent or lessen the skin reactions that indicate an allergy, and so can make the test results unreliable.

Contraindications

Contraindicated in patients with Parkinson's disease, newborns, and hypersensitivity.

Side Effects

Central Nervous System - Drowsiness, headache, GI upset, unsteadiness, headache, depression dizziness and incoordination.

Skin - Rash.

Gastrointestinal - Nausea, vomiting, diarrhea or constipation, loss of appetite or increased appetite and stomach pain.

Miscellaneous - Weight gain, perspiration or allergic reactions and urinary difficulty or retention.

Storage

Store it at room temperature (25°C).

Pharmacology

Pharmacodynamics

Cinnarizine is an antihistamine and a calcium channel blocker. Histamines mediate a number of activities such as contraction of smooth muscle of the airways and gastrointestinal tract, vasodilatation, cardiac stimulation, secretion of gastric acid, promotion of interleukin release and chemotaxis of eosinophils and mast cells. Competitive antagonists at histamine H1 receptors may be divided into first (sedating) and second (non-sedating) generation agents. Some, such as Cinnarizine also block muscarinic acetylcholine receptors and are used as anti-emetic agents. Cinnarizine through its calcium channel blocking ability also inhibits stimulation of the vestibular system.

Mechanism of Action

Cinnarizine inhibits contractions of vascular smooth muscle cells by blocking L-type and T-type voltage gated calcium channels. Cinnarizine has also been implicated in binding to dopamine D2 receptors, histamine H1 receptors, and muscarinic acetylcholine receptors.