The New Straits Times, December 4, 1995
Q: My neighbour was recently admitted to the hospital after he was found to be in coma. According to the neighbour's sister, the patient had ingested a few tablets of heart pills known as "propranolol" prior to the incident. Could you explain to us what is to be expected?
A: There are many causes of coma. In this instance, we need more information about the victim and the circumstances that led him to the coma before we can ascertain that this is caused by the propranolol.
The effects of propranolol poisoning or overdose are highly variable and may depend on factor such as the underlying medical disease or other medications taken concomitantly. But there is enough information on what is to be expected from propranolol poisoning. We highlight these affects with the hope that readers are more aware of the potential dangers of propranolol use.
Propranolol belongs to a group of drugs known as beta-blockers. Besides propranolol, there are many other beta-blockers available. Generally, they are used for treating heart disease and other cardiovascular problems such as heart rhythm disturbance, heart attack and hypertension but they are also found to be useful for controlling migraine headaches and glaucoma.
In the case of an accidental poisoning or overdose involving propranolol, the most common or classic features would be the lowering of blood pressure the heat beat.
Thus the patient is usually described to experience a state of hypotension and bradycardia. In addition to this, the patient may also develop coma or even seizures. Due to the central effects of propranolol and some other beta-blockers, propranolol is able to enter the brain quite readily. Some individuals, especially children and patients with unstable diabetes, may also develop hypoglycaemia, a state of low blood sugar.
The toxic effects from propranolol may be seen as early as 20 minutes after ingestion and may last for up to a few days. Some individuals may be very susceptible to propranolol. They may develop severe or even fatal reactions even with the usual therapeutic doses.
There are no clear-cut guidelines to assess severity from propranolol poisoning. We consider ingestion of anything more than two to three times the therapeutic dose as potentially toxic. Though this may be the case, we recommended that all individuals suspected of propranolol poisoning be brought to the attention of a medical officer as soon as possible.
