Central antitussive effect of codeine in the anesthetized rabbit.

Abstract

BACKGROUND:

Codeine represents a commonly used drug to suppress cough. Central antitussive effect of codeine has been confirmed in a number of animal studies. However, available data related to antitussive activity of codeine in rabbits are very limited.

OBJECTIVE:

We investigated the effects of codeine on cough, single expiratory responses (expiration-like reflex) induced by mechanical tracheo-bronchial stimulation, and on the sneeze reflex in the anesthetized rabbit.

MATERIAL AND METHODS:

Twenty pentobarbitone anesthetized spontaneously breathing rabbits were used for the study. Increasing doses of codeine (codeinum dihydrogenphosphate, Interpharm) were injected intravenously (iv); 0, 0.15, 0.76, and 3.78 mg/kg of codeine dissolved in saline, 0.25 ml/kg) or intracerebroventricularly (icv); 0, 0.015, 0.076, and 0.378 mg/kg of codeine dissolved in artificial cerebrospinal fluid, 0.033 ml/kg.

RESULTS:

Both iv and icv injections of codeine led to a dose-dependent reduction of coughing provoked by tracheo-bronchial stimulation; however, the doses differed substantially. The effective cumulative dose for a 50% reduction in the number of coughs was 3.9 and 0.11 mg/kg after iv and icv administration of codeine, respectively; representing about 35-fold higher efficacy of the icv route. The numbers of expiration-like responses and sneeze reflex responses remained unchanged.

CONCLUSIONS:

The study confirmed the central antitussive effect of codeine, but showed a low sensitivity of sneeze and expiration reflex to codeine. We validated the experimental model of an anesthetized rabbit for studies on central antitussive action.

• Authors: Michal Simera, I Poliacek, J Jakus
• Journal: European journal of medical research (Eur J Med Res) Vol. 15 Suppl 2 Pg. 184-8 (Nov 04 2010) ISSN: 0949-2321 [Print] England
• PMID: 21147648 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antitussive Agents
• Codeine

Topics

• Anesthesia
• Animals
• Antitussive Agents (pharmacology)
• Brain (drug effects, physiology)
• Codeine (pharmacology)
• Electromyography
• Female
• Male
• Rabbits