The makers of a treatment option for opioids, like heroin, took a beating after the U.S. Food and Drug Administration doubted the efficacy of their drug in a review, stating the dosage was "not high enough."

The verdict traveled fast as their shares subsequently dropped 43 percent.

Titan Pharmaceutical Inc.'s marketed their implant drug Probuphine that could pump around-the-clock doses of buprenorphine, a class of medication that prevents an addict from relapsing by producing the same high. Opioids include a number of therapeutic and illicit drugs such as morphine, heroin, codeine, oxycodone and hydrocodone

"While the placebo group had even more discouraging results, supporting the conclusion that Probuphine does have an effect on drug use," reviewers stated in the document. "Overall, the response was not what one might hope for, given that the product ensures compliance with the medication for six months. It prompts speculation that the dose is simply not high enough."

The concern was that four Probuphine implants released doses of the medication nearly a third less than what's released by current oral options for opiate addicts.

"It is possible that the dose is sufficient to provide some agonist effects but not to block the effects of exogenous opioids," regulators added. "Potentially, Probuphine could deliver just enough buprenorphine to allow patients to continue to use illicit opioids without experiencing withdrawal when they stop."

The drug is unlike other alternative opiate replacements. Probuphine is inserted surgically beneath the skin of the upper arm by trained providers, however the FDA also blasted concern on whether it could potentially lead to surgical complications.

The FDA announced their disapproving review ahead of schedule. They were expected to discuss the drug's status on safety and efficacy on March 21.

According to the Opiate Freedom Center, opioid dependence affects nearly seven million Americans every day. Current treatments aside from buprenorphine, include oral medication such as methadone, which replaces the use of illegal opiates and is consumed as a solution or powder and naltrexone, an opioid antagonist that's usually taken as an oral tablet.

Today, buprenorphine is taken daily as sublingual tablets, such as Subutex and Suboxone that dissolve under the tongue. Titan said Probuphine is surgically implanted under the skin within 10 to 15 minutes and for six months administers a constant supply of buprenorphine.