Health Canada has announced the recall of all 60-milligram tablets of the prescription drug pms-Phenobarbital because some oversized tablets were recently found in the Canadian market.

The oversized tablets contain more Phenobarbital than the label indicates, posing an accidental overdose hazard that can be life-threatening.

Those who take a higher-than-recommended overdose also run a risk of falling into a coma or experiencing cardiac arrest, Health Canada says.

Pms-Phenobarbital is used to treat anxiety, sleep disorders and seizures. Symptoms of a possible overdose may include:

• Uncontrolled eye movements.
• Lack of muscle co-ordination.
• Impaired speech.
• Extreme drowsiness.
• Decreased breathing and heart rate.

Those experiencing such symptoms are advised to immediately contact emergency services. Consumers who have already used the drug are advised to contact a doctor.

"Health Canada advises consumers currently using pms-Phenobarbital 60mg to return this product to their pharmacist for a replacement," Health Canada said in a release Friday.

"Consumers should not stop taking their medication without consulting a health-care professional, as abrupt discontinuation of this medication can cause symptoms of withdrawal, ... and, if used to treat seizures, can result in an increase in seizures."

The drug's distributor is Pharmascience Inc.

There have been no reports of adverse reactions associated with consumption of the drug.

Consumers seeking more information can contact Health Canada at (613) 957-2991 or toll-free at 1-866-225-0709.