Peuckmann, V., Elsner, F., Krumm, N., Trottenberg, P., & Radbruch, L. (2010). Pharmacological treatments for fatigue associated with palliative care. Cochrane Database of Systematic Reviews, 11, CD006788.

To determine the efficacy of pharmacological treatment on nonspecific fatigue in palliative care, including patients with advanced cancer and other chronic conditions associated with fatigue.

Databases searched were EMBASE, PsychLit, CENTRAL, and MEDLINE. Reference lists of identified articles were reviewed for inclusion, and textbooks were handsearched. Conference proceedings of the American Society of Clinical Oncology (ASCO) from 2000 to 2008 and the 2005 meeting of the European Cancer Conference were included in the search.

An extensive listing of keywords and specific search methods per database are provided in the article.

Studies were included in the review if

• They were randomized, controlled trials
• The primary outcome was fatigue or related terms, such as asthenia
• Participants were 18 years or older
• The study included evaluation of the effect of pharmacologic treatment of fatigue with psychostimulants, amantadine, corticosteroids, donazepine, and antidepressants if used for the treatment of fatigue. 

Studies were excluded if they studied megestrol or focused on physiologic deficiencies, such as lack of hemoglobin and use of erythropoietin.

Initial searching provided 2,000 titles. Of those, 22 met the inclusion criteria. They included data from 11 drugs:  amantadine (6), pemoline (3), methylphenidate (3), dexamphetamine (2), paroxetine (2), acetyl-L-carnitine (2), testosterone (2), fluoxetine (1), donepezil (1), modafinil (1), and acetylsalicylic acid (1). If two or more studies of the same medication could be analyzed in the same subpopulation of patients, meta-analysis was performed. Meta-analysis was performed for amantadine, pemoline, methylphenidate, and modafinil.

• The final sample of 22 studies included 1,632 patients.
• Studies were performed in patients with multiple sclerosis (MS) (10), HIV (4), cancer (6), postpolio (1), and endstage chronic obstructive pulmonary disease (COPD) (1).

Most studies showed some beneficial effect; however, a substantial similar placebo effect was often observed.

Amantadine

• Meta-analysis was conducted for three (n = 154) studies comparing amantadine to placebo in patients with MS.
• Standard mean difference (SMD) favored amantadine (SMD = 1.68; 95% confidence interval [CI] [1.24,1.92]; Z = 12.76; p < 0.00001).
• No statistically significant heterogeneity existed.
• Study samples were generally small, and several methodologic weaknesses were seen.

Pemoline

• Pemoline was used in three studies on MS.
• Meta-analysis demonstrated no benefit (SMD = –0.11; 95% CI [–0.42, 0.2]; Z = 0.71; p = 0.48).
• There was significant heterogeneity among the studies.

Methylphenidate

• Two studies in patients with cancer were included.
• There was a slightly superior effect compared to placebo (SMD = 0.49; 95% CI [0.15, 0.83]; Z = 2.86; p = 0.004).
• There was significant heterogeneity.

Dextroamphetamine

• Two studies compared the drug to placebo in patients with cancer. No significant benefits were seen.

Paroxetine

• There were no significant effects demonstrated in one study in patients with COPD and one in patients with cancer.

Testosterone

• No significant effects were demonstrated in studies on HIV.

Acetyl-L-carnitine

• No significant effects were shown in one study on cancer and one on MS.

Modafinil

• Meta-analysis in two studies on MS showed no significant effect.

Donepezil

• One study in 142 patients with cancer showed no benefit compared to placebo.

Other

• Fluoxetine was inferior to testosterone in one study on HIV.
• Acetylsalicylic acid was associated with relief of fatigue compared to placebo in one study on MS.

Methylphenidate and amantadine showed promise for reducing fatigue in patients with advanced disease. Amantadine has not been studied in patients with cancer-related fatigue, but it has been shown to be effective in patients with MS. The meta-analysis included only a few studies and the evidence was weak, pointing to the need for additional research in this area. It is not clear whether amantadine would be useful for patients with cancer, as this has not been studied.

The analysis was performed only in palliative care populations and did not include studies of methylphenidate in patients with cancer during active treatment, which also have shown some efficacy. However, side effects included insomnia, anorexia, behavior change, and vertigo in studies reviewed with methylphenidate. In addition, although statistically significant, effect sizes were small. These findings suggest that use in patients with cancer, who also may experience anorexia and sleep disorders from other causes, has potential benefits that would need to be balanced with potential adverse effects. Carnitine, acetylsalicylic acid, and modafinil have been used in a few studies with positive results. These drugs warrant additional investigation to confirm efficacy in different patient populations with fatigue.