Use of promoters of erythropoiesis, antidepressants and stimulants used for attention deficit disorder can improve excessive fatigue in patients with cancer, according to an article in Issue 1 (2008) of the Cochrane Database of Systematic Reviews.

"Fatigue is difficult to treat as it usually has a number of contributory causes - many of which are not fully understood," said lead investigator Dr. Oliver Minton. Patients and professionals alike may consider tiredness as an unavoidable part of cancer treatment, Minton said, rather than a problem to recognize and address.

Among other therapies, drugs can improve some symptoms of fatigue in patients, said Minton, a clinical researcher at St. George's University of London, U.K.

The review analyzed 27 studies (total, 6,746 patients) that examined the effectiveness of certain drugs for relieving symptoms of cancer-related fatigue. Agents tested were methylphenidate, a stimulant typically used to treat attention deficit disorders and concentration problems, erythropoietin and darbepoietin, paroxetine, a selective serotonin reuptake inhibitor used to treat depression and anxiety disorders, and progestational steroids.

Minton said "We found that drugs which improve anemia caused by chemotherapy [also] improve fatigue."

In 14 studies, erythropoietin or darbepoietin proved more effective than usual care or placebo in relieving cancer-related fatigue. However, Minton said that risk or occurrence of side effects, such as aggravating hypertension and thromboembolic events, might limit use of these drugs.

Although they appear promising, patients should also keep in mind that "the erythropoietin findings apply only to cancer patients with anemia," not to all cancer patients, said David Spiegel, MD, psychiatrist and professor at Stanford University School of Medicine. He had no affiliation with the review research.

Minton and his team also found two studies with preliminary evidence for an improvement in cancer-related fatigue with the use of the psychostimulant methylphenidate.

This finding for psychostimulants is an interesting one, because such drugs can be helpful, but they can also create dependency, Spiegel said. Furthermore, the reviewers noted that additional studies are required to confirm this evidence and to assess potential side effects.

The existing research also showed that paroxetine and progestational steroids failed to improve symptoms of tiredness. As a result, the authors say that no evidence exists to support their use for the treatment of cancer-related fatigue.

As for the optimum fatigue treatment, it is still unclear, Minton said. There is little consensus among researchers on how to measure fatigue, which makes gauging the effects of medication difficult.

Although it is common, cancer-related fatigue is difficult to treat effectively for all patients all of the time. "The review looked at one area of treatment using drugs, but exercise and psychological interventions may also help," Minton said.

The most important message for patients is to be aware of the effects of fatigue, and how they can affect everyday life, such as reading, self-care and daily activities, Minton said.

"If patients start to experience these problems having been pre-warned then it may reduce the distress associated with fatigue. It is worth discussing the expected symptoms and possible treatment options with your doctors before, during and after any treatment ends.

Patients can experience fatigue at the time of diagnosis, on treatment and in patients with more advanced disease. It can also occur after treatment - even when they are free of cancer. There may be options for treating it at all of these stages," Minton said.