The big companies have clung to the known drugs because they worked so well for so long.

It still takes some money for a known safe drug to be developed into a known effective drug (for an alternate use).

Opium is one of the oldest known drugs.

Colchine is one of the oldest known antimitotic drugs and in the past years much research has been done in order to isolate or develop compounds having similar structure but high activity and less toxicity.

Although active transport is not modeled by the artificial PAMPA membrane, up to 95% of known drugs are absorbed by passive transport.

When dapsone was used alone, the M. leprae population quickly evolved antibiotic resistance; by the 1960s, the world's only known anti-leprosy drug became virtually useless.

Federal officials argued that it made sense to rapidly expand knowledge of the only known effective drug before investigating others that looked far less promising.

Although a vaccine can prevent smallpox, no known drugs can cure the disease after it has developed.

If no known drugs bind to a target, then druggability is implied or predicted using different methods that rely on evolutionary relationships, 3D-structural properties or other descriptors.

Testing for alcohol and other known dementia-inducing drugs may be indicated.