Accutane, a powerful drug used for the treatment of acne when all else fails, may heighten the risk of heart and liver problems in users, new research suggests.

Most of the 14,000 participants in the study were young -- their median age was 19 -- and had used the drug for months. The median length of treatment was 21 weeks. The investigators found that heightened levels of blood cholesterol, triglycerides and blood liver function were more common than reported in previous studies.

Raised triglyceride fat levels were observed in 44 percent of patients who had previously normal levels; increases in total cholesterol occurred in 31 percent of users.

Earlier trials had shown Accutane to raise triglycerides in 25 percent of patients, while increasing cholesterol in just 7 percent of users, according to the drug's label. Higher triglyceride and cholesterol levels have been linked to increased risk of heart attack and stroke.

In most cases, blood levels normalized to pretreatment levels after Accutane use was discontinued. Liver enzyme levels returned to normal within three months followiong treatment in 92 percent of the patients who were monitored. Cholesterol levels returned to normal during the same period in 79 percent of patients, and triglyceride levels returned to normal in 80 percent of patients.

However, the researchers suggested that further monitoring would be useful to learn whether there might be long-term cardiovascular and liver disease risk.

. Previous research also linked isotretinoin to birth defects. Last year, the Food and Drug Administration issued regulations requiring that females be screened for pregnancy before the drug is prescribed. The drug has been blamed for hundreds of miscarriages and birth defects each year.

Accutane was approved in 1982 for the treatment of severe, disfiguring acne that was not responsive to other forms of treatment.