Zolpidem, more popularly known as Ambien, is a popular sleeping pill that is supposed to help you fall asleep and awaken refreshed. However, those taking this medication may be getting more than what they’ve bargained for. A new study by the US Substance Abuse and Mental Health Services Administration (SAMHSA) found that there are a growing number of emergency room visits from adverse reactions from the drug.

The researchers reviewed data from the the Drug Abuse Warning Network (DAWN), which is a public health surveillance system that studies reports from various hospital networks across the nation. The adverse reactions they found included hallucinations, paranoia, confusion and agitation, which led to 19,487 emergency room visits in 2010, a 220% increase from 2005. Over half of these visits involved the user taking the sleeping pill with alcohol or other medications, like antidepressants, sedatives or analgesics.

Over two-thirds of those visitors were women, who appear to be much more vulnerable to the drug compared to men. Three-quarters of those visitors were 45 years old or older.

Back in January, the FDA announced that it will require drug makers that produce sleep medications that contain zoplidem to cut their recommended dosages for women by half. This cut came after recently published research suggested that blood levels of the drug were still elevated in the morning, putting the user at risk of severe impairment and drowsiness. There was no dosage change recommendation for men.

“Although short-term sleeping medications can help patients, it is exceedingly important that they be carefully used and monitored,” said SAMHSA Administrator Pamela S. Hyde in a press release. “Physicians and patients need to be aware of the potential adverse reactions associated with any medication, and work closely together to prevent or quickly address any problems that may arise.”