Shares of the company fell as much 7.47 percent to 1,573 pence, the lowest since May, 2014. They were the top loser on the FTSE 100 bluechip index and the pan-European Stoxx 600 index.
Hikma now expects full-year revenue to be in the range of $2.0 billion-$2.1 billion at constant currency, down from its earlier forecast of $2.2 billion (1.7 billion pounds).
Earlier this month, the company said approval for its generic version of GlaxoSmithKline Plc's blockbuster lung drug Advair was unlikely in 2017.
Hikma and its partner Vectura Group Plc are in a race with Mylan to launch the first U.S. generic copy of Advair. The FDA has already delayed approval of Mylan's version.
Hikma on Friday lowered its 2017 revenue forecast for its generics business to $670 million, down from its earlier forecast of $800 million.
"This assumes we do not launch our generic version of Advair Diskus in 2017 and reflects the intensifying competitive environment in the U.S.," the company said in a statement.
Hikma maintained its full-year revenue estimate for its injectables unit at a range of $800 million-$825 million, with core operating margin seen in the high 30s.
(Reporting by Sanjeeban Sarkar and Tenzin Pema in Bengaluru; Editing by Sunil Nair)