Health insurer Aetna announced Tuesday that it will provide the lifesaving opioid overdose reversal drug Narcan to some of its customers at no cost.

The medicine will be available to customers who are insured under Aetna's commercial plans, such as those through work, beginning on Jan. 1. The company said it is the first national insurer to make such a provision available to its customers.

Narcan is a nasal spray that works to awaken someone who has overdosed on an opioid such as a prescription painkiller or heroin and also works to combat more potent drugs like fentanyl. A package of Narcan, which includes two nasal sprays, typically costs as much as $150. Aetna customers will be able to obtain two packs at at time.

Some states allow naloxone, the active drug in Narcan, to be given to patients without a prescription. Prior to the announcement Aetna already paid for most of the cost of the drug, and patients paid between $30 and $40 in co-pays.

According to data Aetna received from Narcan's manufacturer, nearly 35 percent of enrollees didn't pick up their prescriptions between January and June. They also found that people were less likely to fill a prescription when the co-pay increased. The data show that 76.7 percent of prescriptions weren't picked up if they had a co-pay of between $100.01 and $150, compared to a 46.1 percent drop in prescription pickups if the copay was between $40.01 and $50.

“Cost is clearly a factor in whether individuals with substance abuse disorder obtain medication that could save them from a fatal overdose,” said Dr. Harold Paz, executive vice president and chief medical officer of Aetna. “By eliminating this barrier, we hope to keep our members safe until they are ready to address their addiction.”

Aetna also said it was limiting the number of opioids prescribed for acute pain and after surgery to a seven-day supply. Many people who become addicted to opioids do so after receiving a prescription from a doctor to treat pain. When they are unable to obtain more medication, they turn to heroin as a cheaper alternative which carries a similar high. Deaths from opioids reached 33,000 in 2015, according to the latest available federal data.