The Food and Drug Administration yesterday issued rules that require all nonprescription drugs sold in the United States to be packaged in tamper-resistant containers.

The new FDA regulation will affect 200,000 to 300,000 separate products, all of which will have to be manufactured with tamper-resistant packages in either 90 or 180 days unless a special exemption is granted.

The regulation allows manufacturers to choose among a variety of tamper-resistant packages: foil seals under the cap, shrink-bands around the cap and bottle or "bubble" packages in which plastic is shrunk around the bottle or individual capsule and then glued to a backing, among others.

Manufacturers will be required to print distinctive designs on the tamper-resistant material so that it will be easier for consumers to detect tampering. Each package must also include a printed warning that the package is tamper-resistant and should be examined and not used if there is evidence of tampering.

Secretary of Health and Human Services Richard S. Schweiker estimated that the regulation will cost between $20 million and $40 million, all of which is expected to be passed to the consumer in the form of a 1- to 2-cent rise in the price of nonprescription drugs. The nonprescription drug industry, whose own recommendations bear a strong resemblance to the final regulation, praised the new rules.

The regulation was written and passed through the bureaucracy in less than a month, in response not only to the seven murders by cyanide-contaminated Tylenol in Chicago, but also to the wave of copycat poisonings and product tamperings since that time.

The FDA alone has recorded nearly 300 such incidents, more than three dozen of them confirmed by FDA investigation. Many others reported to police or health officials have not been counted by the FDA.

Under the regulation, tamper-resistant packages must have some barrier to being opened and the breaking of the barrier must be obvious to the consumer so that a visual warning of tampering is provided.

Schweiker said in a statement yesterday that "While it is virtually impossible to make any package tamper-proof, it is possible to manufacture packages in such a way that tampering is much more difficult and that if a product is tampered with, it can more easily be detected by a careful consumer."

Most nonprescription capsule and liquid products that are especially susceptible to tampering, including eyedrops and mouthwashes, would have to be in the new packages in 90 days.

Tablets and suppositories, which are considered less susceptible to tampering, would be required to have tamper-resistant packaging in 180 days.

Foods and skin-care products are not covered by the regulation.

Retailers can sell existing stocks of over-the-counter drugs for 15 months. But Schweiker said some improved packages might be on the shelves within a week or two.

An industrial packaging specialist, David W. Powell of 3M Co., said that some drug companies "that have a big investment in a brand name," such as Tylenol, will use not one but more likely two or three separate barriers on a package to try to assure confidence in that brand.

Powell said the most popular packaging will be foil seals on the bottle beneath the cap, mostly because the materials and machinery are readily available. For other packaging, such as shrink-bands, it is necessary to use custom-designed machinery, which can take many months to put in place.