Poor healthcare-screening programmes and long waiting times for some treatments are forcing doctors to prescribe more medicines than should be necessary for their patients.
The claim was made yesterday by Limerick-based family doctor, Dr Mary Gray, who said there was an over-reliance on drug therapies in the State.
Dr Gray, a member of the GP committee of the Irish Medical Organisation, said poor disease screening for conditions such as diabetes and the fact that medical card patients have to wait up to a year to see a physiotherapist, meant patients were being prescribed painkillers, she said.
Dr Gray's comments followed the admission at a London scientific meeting by the worldwide vice-president of genetics at GlaxoSmithKline (GSK) that fewer than half of the patients prescribed some of the most expensive drugs actually derived any benefit from them.
Mr Allen Roses said drugs for migraines, osteoporosis and arthritis work in about half the patients who are given them.
Drugs for Alzheimer's disease work in fewer than one in three patients and those for cancer are only effective in a quarter of patients, he added.
He suggested this was because the recipients carry genes that interfere in some way with the medicine.
"The vast majority of drugs - more than 90 per cent - only work in 30 or 50 per cent of the people," he said.
Dr Gray said doctors would be aware from clinical trials that not all drugs worked on all patients.
"A 30 per cent effectiveness for cancer treatment would be excellent but for an antibiotic that would be very poor," she said.
"We would be aware in prescribing that there would be patients for whom a particular drug would not be effective and we would be aware that could be up to 50 per cent but how we manage that is by reviewing patients regularly.
"If a drug is not effective we would change to an alternative brand and more often than not we would find a brand that would be effective for a particular patient," she said.
Despite the costs, doctors had to keep prescribing until they found an effective remedy, she added.
Meanwhile, Mr Brian Murphy of the Irish Pharmaceutical Healthcare Association emphasised no product was placed on the market that had not been approved by an independent regulatory authority.
Here the Irish Medicines Board assessed products for efficacy and safety before they were licensed, he said.
He added that it would be unfortunate if Mr Roses comments put people off taking medication which had been prescribed for them by their doctor.