(Reuters) - Trevena Inc’s opioid injection to treat acute pain could be abused and potentially lead to overdose, staff reviewers of the U.S. Food and Drug Administration said on Tuesday, sending the drugmaker’s shares down 66 percent.

The treatment, oliceridine, aims to manage moderate-to-severe acute pain in adult patients for whom an intravenous opioid is necessary and the injection should be administered in hospitals and ambulatory surgery centers.

FDA staff reviewers said here overall assessment of the abuse-related data from studies suggests that Trevena's oliceridine has an abuse and overdose potential and could lead to physical dependence that is similar to other such treatments.

Oliceridine belongs to a class of opioids that includes morphine and fentanyl, which are commonly prescribed for pain.

An expert panel to the FDA is expected to vote on the efficacy and safety of the treatment on Thursday. Their meeting comes at a time when abuse of opioid drugs has reached epidemic proportions.

Addiction to opioids - mainly heroin and prescription painkiller fentanyl - has emerged as a serious public health crisis in the United States, especially in rural areas, resulting in the death of over 70,000 people last year.

While the FDA is not obliged to follow the panel’s advice, it generally does so.

Trevena shares were trading at 99 cents before the bell on Tuesday. The company’s shares have risen 86 percent this year.