QUESTION FROM READER:ANESTHESIA

Q:My wife recently had a severe, near fatal reaction when given Diprivan (propofol) in a routine operation. All doctors in the hospital tried to cover it up or dismiss it. Where can I discover truthful data on the side effects of propofol? PJ Nettle

Propofol is considered a wonder drug over the older anesthesia, sodium pentothal. The onset is rapid (it starts working in 40 seconds after the start of injection), and the patient also eliminates the drug from his body more quickly than with earlier anesthetic drugs. Consequently, there are fewer after effects, including nausea. According to Stuart Pharmaceuticals, the American company which manufacturers Diprivan, writing in the Physician’s Desk Reference, patients given a single dose to induce hypnosis, plus kept on maintenance levels of 0.1-0.2 mg per kg of weight per minute of propofol for up to two hours are awake, responsive and oriented after eight minutes. The drug also seems to leave the body quickly. Again, according to Stuart, 70 per cent of the injected drug was recovered in the urine of six subjects after 24 hours and 90 per cent within five days.

For all of its great benefits, there is a good deal that the manufacturers don’t know about the drug, including how much is necessary in the blood to maintain anesthesia. And also a good number of patients who can react to it. It should not be used in patients with impaired cerebral circulation because it can cause blood pressure to substantially decrease.

Diprivan is a white oil in water emulsion, which contains soybean oil, glycerin and egg lecithin; one anesthetist we spoke with likened it to injecting ice cream into patients. This means that anyone with allergies to soy products or eggs may react.

Furthermore, Stuart also says that strict sanitary condition must be maintains while handling Diprivan since the suspension vehicle used for it is capable of supporting rapid growth of microorganisms. Furthermore, the injection shouldn’t be administered through the same intravenous catheter as blood because we don’t know if the two substances are compatible; indeed, test tube studies have shown that blood mixed with a portion of the emulsion have caused it to clump together.

There is also a possibility that the premedication generally used, particularly narcotics (morphine, meperidine and fentanyl), or combinations of narcotics and sedatives (such as benzodiazepines or barbiturates), may increase the anesthetic effects of Diprivan and may also caused more pronounced changes in blood pressure and output of blood from the heart. This may also be the case with the inhalational drugs like isoflurane and halothane, but nobody really knows the exact effect. Because it decreases blood pressure, propofol should not be used with patients who have decreased cerebral blood pressure.

Among the copious side effects noted by this drug, Stuart reports both low and high blood pressure, apnea (inability to breathe), abnormal heartbeat and depression of heartbeat, and, less commonly, heart block, generalized and localized seizures, poor blood supply to the heart and central nervous system.

Among a column of other side effects, the PDR also lists upper airway obstruction, bronchospasm, other breathing difficulties, including hyperventilation and hypoventilation (abnormally high and low breathing rates, respectively), delirium and seizures.

Any one of these effects could account for your wife’s extreme reaction. Your story points up the little known fact that any form of anesthesia, even the new “miracle” variety, carries risks which should be explored before they get you under the knife.