Paracetamol Domperidone

Domperidone may be the antiemetic of choice, but as the patient has very little metabolic and synthetic liver function, owing to massive hepatocellular necrosis secondary to the hepatotoxic effects of the paracetamol overdose, accumulation of the domperidone may occur. However, it may be of benefit as a pro-kinetic agent. 

The absorption of paracetamol is decreased by anion exchange resins (colestyramine), whereas some drugs used to control nausea and vomiting, such as metoclopramide and domperidone, hasten the absorption of paracetamol. 

Metoclopramide increases the rate of absorption of paracetamol and raises its maximum plasma levels. Similarly, domperidone may increase the rate of absorption of paracetamol. 

Intravenous metoclopramide 10 mg increased the peak plasma levels of a single 1.5-g dose of paracetamol by 64% in 5 healthy subjects (slow absorbers of paracetamol), and increased its rate of absorption (peak levels reached in 48 minutes instead of 120 minutes), but the total amount absorbed remained virtually unaltered. Oral metoclopramide also increases the rate of paracetamol absorption, probably because the rate of gastric emptying is increased. Similarly, the speed of absorption of paracetamol may also be increased by domperidone. This interaction is exploited in Paramax (a proprietary oral preparation containing both paracetamol and metoclopramide) to increase the effectiveness and onset of analgesia for the treatment of migraine. This is obviously an advantageous interaction in this situation. 

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