Pssst! Pharmaceutical companies! Want to know a secret? One of the easiest ways to get investors jazzed up about your company is to run a clinical trial with a commercially available drug, then add naltrexone to it. Animal and human drug supplier Alpharma (NYSE:ALO) has done just that, adding naltrexone to the company's lead drug to treat chronic pain.

Alpharma held a conference call today to announce results from a phase 2 trial testing the company's already approved oral morphine pain drug, Kadian, with naltrexone. The goal of the trial was to show that Kadian was just as safe and effective with naltrexone as without.

With shares up nearly 10% for the day, it's easy to guess how the trial results fared. The Kadian and naltrexone combination drug showed the same efficacy and levels of adverse events as the non-naltrexone version.

The idea behind adding naltrexone to the drug is that if drug abusers try to crush it to hasten its entry into the bloodstream, as they often do with opioids, the company's special formulation of naltrexone will be released, rendering the drug much less effective. Naltrexone is often used to treat drug dependence and alcoholism, so it makes sense that it should perform in this way.

With positive phase 2 trials behind it, Alpharma plans to begin enrolling patients for a phase 3 trial in the fourth quarter and, if successful, hopes to have the Kadian-naltrexone combination drug on the market in 2009.

For the first two quarters of 2006, sales of Kadian have reached $69 million and increased 55% in the most recent quarter compared to last year. If Alpharma can usher this abuse-resistant version of Kadian through the clinical trial process, the company should have no problem keeping up this sort of sales growth for the drug for a quite a while.

Many companies are working on designing drugs using naltrexone and its related chemical entities. Whether naltrexone is used to treat alcoholism or drug dependence, autoimmune diseases or bowel disorders, this generically available compound is very popular because of the drug's long history of proven safety and minimal side effects. Alpharma can now be added to the lengthy list of naltrexone users.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. The Fool has a disclosure policy .