The Food and Drug Administration approved a new drug from Bayer to treat dangerously high blood pressure in the lungs.

The agency cleared the company's Adempas tablets for patients with two forms of pulmonary hypertension, which forces the heart to work harder to pump blood to the lung's arteries. When left untreated, the disease can lead to lung transplantation and death.

Regulators said late Tuesday they approved Adempas to treat the condition in patients who have undergone surgery or who cannot undergo surgery, to improve their ability to exercise. The agency also approved the drug for patients whose pulmonary hypertension is inherited or caused by other diseases.

Adempas is the first drug approved in a new class of therapies called soluble guanylate cyclase stimulators. The drugs work by relaxing the arteries, which increases blood flow and decreases blood pressure.

The drug will carry a boxed warning label alerting doctors and patients that it can cause birth defects in developing fetuses if used by pregnant women.

Women will only be able to take the drug after registering in a special program that requires regular pregnancy testing and education on contraception.

Common side effects with Adempas seen in clinical trials included headache, dizziness, indigestion, diarrhea and vomiting.

Bayer Healthcare is a subsidiary of German conglomerate Bayer, with U.S. offices in Wayne, N.J.

Bayer HealthCare is a unit of German drugmaker Bayer AG. U.S.-traded shares of Bayer AG slipped 9 cents to $113.98 in morning trading.