The Department of Defense announced this week that it will start testing U.S. servicemembers for prescription drugs containing hydrocodone, seen here, after a spike in prescription drug abuse in the military. The DOD will also test for anti-anxiety medications containing benzodiazepine.

TOKYO — The Defense Department announced an expansion of its drug testing program Wednesday to include widely abused prescription medications containing hydrocodone and benzodiazepine, but it’s offering an unprecedented 90-day amnesty period for servicemembers to come clean or get treatment.

The painkiller Vicodin, containing the synthetic opioid hydrocodone, and the anti-anxiety medications Xanax and Valium, which contain benzodiazepine, are among the most abused prescription drugs on the market, which is why they are being added to the list of testable substances, according to Joe Angello, DOD director of operational readiness and safety.

The program already tests for the opiates codeine and morphine.

But for the first time in more than 40 years of drug testing, the DOD is giving troops a three-month notice before the testing begins.

“The memorandum is giving you a 90-day warning order,” Angello said in a DOD release announcing the new policy.

This way, servicemembers addicted to prescription drugs can seek medical help without fear of penalty, he said.

The testing is not an all-out ban of the substances. Servicemembers with prescriptions for the drugs will not be subject to disciplinary action for using them within the dosage and time prescribed.

In July 2011, after years of war and with increasing numbers of troops returning from Afghanistan and Iraq with combat or training injuries, The Associated Press reported the number of soldiers referred for opiate abuse treatment had been growing steadily for at least a decade. In response to the trend, the Army began limiting the number of painkillers a soldier could be prescribed at one time.

According to Army data provided to AP, referrals for opiate abuse increased from 87 in fiscal year 1999 to 703 in fiscal year 2009. There were more than 670 referrals from October 2009 through June 2010.

Expired medications should be turned in for disposal rather than flushed, Angello said, as they can contaminate the water supply.

baileyn@pstripes.osd.mil