Zoloft (Lustral/sertraline) , Xanax , Demerol - no mention of Jackson taking Seroxat - source Copyright 2009 Times Newspapers Ltd

Drug mix Michael Jackson took is key
Copyright 2009 Times Newspapers Ltd.

http://entertainment.timesonline.co.uk/tol/arts_and_entertainment/music/article6585279.ece



Dr Martyn Lobley
The list of prescription drugs that Michael Jackson was reported to have taken includes drugs from three main chemical classes. Those most frequently referred to are the anti-depressant sertraline, known as Zoloft in the US and Lustral in Britain, the Valium-like tranquilliser alprazolam (Xanax) and the morphine-like painkiller pethidine (Demerol).

It is reported that Jackson collapsed shortly after an injection of Demerol, presumably administered by a doctor or nurse. The timescale is not clear, but the limited interval between the injection and his collapse suggests that the two may have been linked.

All tranquillisers and morphine-like painkillers are known to affect patients breathing patterns, especially if taken in excessive doses. Doctors know that the large single doses of opiates and sedatives given to patients in their final hours to relieve pain could shorten their lives by depressing their respiratory efforts.

When two drugs are given together, especially if they are from different classes, the effects do not simply combine they multiply. Doctors make use of this when treating high blood pressure where low doses of two drugs given simultaneously are often more effective than high doses of one or the other. But the multiplication principle also holds true for unwanted effects. The death of the actor Heath Ledger last year was attributed to the combination of Xanax with another opiate painkiller, oxycodone.

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The sedative effect of previous doses of Xanax, combined with an injection of Demerol, could have been responsible for the apparent shallowness of Jacksons breathing in the minutes that followed. By the time that the 911 call had been logged by the emergency services his breathing had stopped altogether. The sedation resulting from the drug combination may well have removed the desire for him to breathe for himself as surely as if the drugs had been administered by an anaesthetist.

When breathing stops and the heart is deprived of the oxygen required to function a cardiac arrest is inevitable.

As soon as a patient collapses the priority is to re-establish some sort of circulation and to provide essential oxygen, usually by administering cardiopulmonary resuscitation (CPR). If the cause of collapse is known it is mandatory to deal with that too. A collapse as a result of a heart attack is often due to a pulse abnormality known as V-fib (ventricular fibrillation) and a couple of shocks from a defibrillator may restore the hearts normal rhythm.

If the reports are accurate, the short time between the injection and the collapse would mean that the doctor who injected the Demerol would probably have considered administering an opiate antagonist (or antidote) to reverse any respiratory depression.

The effects of the most commonly used antidote, naloxone, are short-acting but the time it buys the emergency response team, allowing them artificially to ventilate a patient, is invaluable.

But even in the best situations, attempts at CPR are not always successful. Jackson was known to be physically frail, reportedly weighing as little as 7st, and to be under great stress. Perhaps it is not surprising that the paramedics and emergency room staff were unable to revive him.

Dr Lobley is a general practitioner in South London