Patients who can't take drugs approved by the Food and Drug Administration have a recent law on their side. It allows pharmacists and doctors to tailor-make some drugs for specific patients -- a process known as "compounding."

The provision was included in the FDA Modernization Act of 1997.

It may involve nothing more than crushing a pill into a powder and mixing it with a liquid. Or it may entail sophisticated scientific operations -- for example, preparing sterile drugs in a germ-free environment.

Experts caution that compounded medications may carry extra inherent risks. But those must be weighed against the benefits for certain patients.

• Compounding may be resorted to when a patient is allergic to some inactive ingredient in the standard version -- necessitating a compound which omits an offending dye or a lactose filler, for example.

• It can also be used to alter the particular strength of a drug to accommodate children or seniors.

• And unlike drugs prepared by manufacturers, compounded drugs can include drugs not approved by the FDA for that specific use.

A bulk drug substance -- the chemical that becomes the drug's active ingredient -- can be compounded if it is listed in a book of widely used drug substances published by the U.S. Pharmacopeial Convention, an independent standard-setting organization.

However, compounded drugs must be prescribed by a physician for a specific patient.

Source: Tamar Nordenberg (FDA Consumer magazine), "Pharmacy Compounding: Customizing Drugs," Consumers' Research, September 2000.