Signs and symptoms: Stable angina usually occurs after a round of physical exertion. Ketotifen was originally patented by Sandoz in the 1970s. Consult your doctor before you begin any exercise programme. The New Frontier of Population Control". Hydroxyurea (hye drox” ee ure ee’ a) is a hydroxylated analogue of urea and an antimetabolite which inhibits the enzyme ribonucleotide reductase, which is necessary for DNA synthesis and cell cycle replication. With patients whose angina or hypertension is complicated by congestive heart failure, care should be taken to differentiate this peripheral edema from the effects of increasing left ventricular dysfunction.