PT - JOURNAL ARTICLE AU - Andrew D Reddick AU - Kirsten Hodge AU - William G Morrison TI - Effect of concomitant opiate ingestion on paracetamol levels in acute overdose AID - 10.1136/emj.2009.083469 DP - 2010 Oct 01 TA - Emergency Medicine Journal PG - 742--744 VI - 27 IP - 10 4099 - http://emj.bmj.com/content/27/10/742.short 4100 - http://emj.bmj.com/content/27/10/742.full SO - Emerg Med J2010 Oct 01; 27 AB - Aim To assess whether the co-ingestion of opiates in acute paracetamol overdose has an effect on the paracetamol level 4 h after ingestion.Methods A prospective observational study was performed in the emergency department of a teaching hospital. The paracetamol levels at 4 h of consecutive patients who had taken an overdose of either paracetamol alone or in conjunction with an opiate were collected over a 4-month period. The data were then analysed.Results After exclusions, the results of 21 patients who took paracetamol alone and 20 who took paracetamol and an opiate showed that paracetamol levels were significantly lower at 4 h if there was co-ingestion of an opiate. Analysis shows that opiate ingestion is a predictor for paracetamol levels at 4 h.Conclusion Co-ingestion of opiate decreases the serum paracetamol level at 4 h. If opiate and paracetamol are taken together, there is a case for a repeat measurement of the paracetamol level if the level at 4 h is lower than would be expected in selected patients.