DIMENHYDRINATE

It competitively antagoise actions of histamine at the H1 receptors causing considerable sedation. It acts by inhibiting vomiting centre stimulation by suppressing hyperstimulated labyrinth. It suppresses end organ receptors or inhibit central cholinergic pathway (in vestibular nuclei). Drug has a potent anti-emetic action which is free from extra pyramidal side effects such as tremor, impairment of muscle tone and abnormal involunatry movements.

Indications

Nausea and vomiting associated with electro-shock therapy, anaesthesia and surgery, layrinthine disturbances, radiation sickness and postfenestration syndrome; motion sickness; vertigo. For prevention of motion sickness, give first dose 1/2 hr. before journey.

Dosage

Adults: 50-100 mg, 3-4 times a day. Children: 5 mg/kg/day in 2-3 divided doses.

Contra-Indications

Hypersensitivity.

Special Precautions

drowsiness, if occurs, donot drive or operate machinery. May mask ototoxic symptoms of some antibiotics. Paediatrics: Contraindicated below 2 years. Pregnany: Safety not established. Lactation: Use with caution. Elderly: Use only, if clearly indicated.

Side Effects

Impaired alertness, sedation, dizziness, dry mouth.

Drug Interactions

Potentiates CNS depressants (alcohol, barbiturates, analgesics, sedatives and neuroleptics), MAOIs, atropine, tricyclic antidepressants enhance antimuscarinic effect. Masks ototoxicity produced by aminoglycosides antibiotics.