Tramadol

There are now a number of case reports, which suggest induction of a serotonin syndrome by combination of tramadol with SSRIs. 16 , 17   Such combinations may be used with caution.  Although no reports of drug interactions with MAO inhibitors have been published, the concomitant use of MAOIs with tramadol is contraindicated as a safety precaution.  Other relevant interactions between tramadol and concomitant medication have not been described.  Initial reports of an interaction between tramadol and coumarins with prolongation of INR could not be confirmed.

In overdose, tramadol produces significant neurologic toxicity such as seizures, coma and respiratory depression, while cardiovascular toxicity seems to be limited to mild tachycardia and hypertension.When seizures do occur with tramadol use, they are commonly of short duration and are easily treatable.  In one reported case of a seizure, the convulsions were induced by naloxone administration.  Hence, although respiratory depression in overdose can be treated with the opioid antagonist, naloxone, reversal of all opioid poisoning should be conducted with low doses, repeated as clinically indicated, to avoid rebound effects including pain, hypertension, tachycardia and seizures.

Competing interests : Professor Schug has been and is involved in clinical research on tramadol, partially funded or supported by Gr?nenthal GmbH, Stolberg, Germany and CSL (New Zealand) Ltd., Auckland.

Correspondence to Professor Stephan Schug, Head, Division of Anaesthesiology, Faculty of Medical and Health Sciences, University of Auckland, PO Box 92019, Auckland, New Zealand. Phone 09 373 7599 ext 6401 fax 09 373 7556,  e-mail s.schug@auckland.ac.nz