More must be done to curb NHS spending on prescription drugs in England, which has more than doubled in a decade to £8.2bn a year, MPs say.
Millions of pounds could be saved if people took generic drugs
The Commons public accounts committee wants GPs to use more generic drugs instead of expensive, branded ones.
The cross-party group of MPs also suggested printing the cost of drugs on packets to discourage patient waste.
The pharmaceutical industry claims new medicines are under-used by the NHS, not over-prescribed.
The MPs also suggested restricting drug firm influence by forcing GPs to declare significant gifts and hospitality.
A recent survey found a fifth of GPs admitted to being more influenced by pharmaceutical firms than NHS advisers over which drugs to prescribe - raising concerns that they were too ready to use expensive branded medicines.
Over the last decade the NHS drugs bill has soared from £4bn to £8.2bn a year.
GPs now prescribe an average of 14 items per person a year - at an average cost of £11 per item.
The National Audit Office has estimated that £200m a year could be saved without affecting patient care by GPs prescribing lower cost but equally effective treatments.
The MPs said at least £100m was estimated to be lost on wasted and unused drugs each year.
BRANDED V GENERIC
In October 2006, a generic version of the cholesterol-lowering statin simvastatin could be bought for £2.34 for a pack of 28 20mg pills
A branded version of the same drug cost £29.69
They said patients must be made aware about the true cost of drugs as the amount they paid in prescription charges bore no relation to the true price of the treatment.
The report also said the government should encourage doctors to become better at medicines management by setting tougher targets in the GP contract.
MPs used the example of cholesterol-lowering statins to illustrate flaws in the system.
They said 28% of prescribed statins in some trusts were the cheaper versions compared to 86% elsewhere.
Committee chairman Edward Leigh said: "Around a quarter of all expenditure in primary care is on drugs and both the volume of drugs prescribed and their total cost are increasing.
"Efficient management by the Department of Health and NHS bodies can however make the drugs bill more affordable without affecting patient care."
Dr Jim Kennedy, prescribing spokesman for the Royal College of General Practitioners, said: "Many of the recommendations are sensible and, of course, we could do better.
"But I would point out that GPs here have the best record for using generic versions of drugs.
"I also think the government could do more with the deals it arranges with pharmaceutical companies.
"Instead of paying for the amount of drugs we use, perhaps the NHS could be charged for the effect they have on say life expectancy or lowering blood pressure so the price reflect their effectiveness and performance."
The Association of the British Pharmaceutical Industry (ABPI) said new, innovative medicines are under-used by the NHS, not over-prescribed.
Dr Richard Barker, ABPI director general, said: "The facts simply do not back the assertion that doctors are unduly influenced by the pharmaceutical industry's marketing activities.
"Not only is the UK the poor relation of comparable countries worldwide in terms of prescribing new, innovative medicines but we also have the highest prescribing rates for generics."
A Department of Health spokesman said generic prescribing was on the increase, and future action would focus on minimising waste.