Took one expired tetracyclineWell I found some pills and took some. at the date, it "expired" 4 years ago. . . One . Is this toxic? . . Best Answer: Tetracycline is one of the drugs that can have very serious effects if taken after expiration, however one tablet that is only three months expired is . is that okay? what could result if l do take it. . . . . I took one Nabumetone 750 mg solid capsule that expired 11 months ago. . . . . . . . . . much relief from pain as you would if you took . .... more