Authority chief executive Shane Solomon will look into automatically dispensing drugs after the discovery last week that patients had been given the wrong pills for diabetes.

At least nine patients out of 63 given Glibenclamide diabetes pills at Lady Trench General Outpatient Clinic were given diltiazem, a drug for hypertension.

Staff informed potentially affected patients after a pharmacist discovered the switch of similar looking white pills last week during a routine check.

The discovery, which is suspected to have been caused by human error, has prompted Solomon to promise to improve the system and consider automation.

Meanwhile, all the patients who may have been given the wrong drugs at the Tsuen Wan clinic will have had their supply checked and replaced by today, an authority spokeswoman confirmed. "We have scheduled appointments with the last four patients who are possibly affected," she said.

The patients were between 50 and 85 years of age, and the drugs were dispensed not longer than six months ago, she added.

There have so far been no complaints of illness from patients who have returned the drugs they were wrongly prescribed.

The spokeswoman said possible side effects for patients not suffering from hypertension taking diltiazem include feeling faint and dizzy.

HA chairman Anthony Wu Ting- yuk and Undersecretary for Food and Health Gabriel Leung spoke over the weekend about their disappointment over the incident.

Wu also apologized for the error and said the authority will investigate the root cause of the problem. The employee responsible for the mix-up may face disciplinary action.

Last month local manufacturer Europharm had to recall its anti-gout allopurinol tablets from sale after an illegally high level of fungus was found in the pills.

Marching Pharmaceutical also recalled 216 products after inconsistencies were found in expiration date labels, while Christo Pharmaceuticals was found to have supplied the authority with unregistered drugs.

Another firm, Unipharm Trading, has been suspected of illegally packaging anti-depressant medication and fabricating the expiry date on painkillers while Luen Cheong Hong has recalled batches of "water for injections" because of labeling inconsistencies.