Untapped potential of antidepressants for cancer

Sep 11 2008

A comprehensive review of current scientific literature, published in the peer-reviewed journal ecancer, has suggested that antidepressants can help the human body fight cancer by boosting its own immune response, amongst other mechanisms.

Not only this but they can help with side effects from chemotherapy such as aiding sleep, stimulating appetite, combating pain and avoiding depression.

Antidepressants work by affecting levels of chemicals known as prostaglandins. These are ephemeral, infinitesimal signallers self-regulating every cell in the body, including those serving mood and immunity. When first discovered they were perceived as a master switch, but are now believed to regulate every component of cellular microanatomy and physiology, including those of the organelles, cytoskeleton, proteins, enzymes, nucleic acids and mitochondria.

Prostaglandins are responsible, paradoxically, for both cell function and dysfunction. Excessive prostaglandin synthesis depresses immune function and may induce cancer.

An ideal anticancer agent would inhibit prostaglandins in such a manner as to shut down the pathogenesis of cancer. The article indicates that antidepressants have such properties.

Report author, Dr Julian Lieb of Vermont, USA, concludes that antidepressants have the potential to arrest, prevent, reverse and palliate cancer. He also points out that short of that they have many other uses in cancer care.

Antidepressants can reduce the severity and frequency of hot flushes in patients treated with chemotherapy, and venlafaxine (Effexor) remit acute neurosensory symptoms secondary to oxaliplatin chemotherapy. The monoamine oxidase inhibitors deprenyl and clorgyline protect nonmalignant cells from ionizing radiation and chemotherapy toxicity, and such antidepressants as nefadazone are capable of reversing chemotherapy-induced vomiting.

The report notes that as the response to antidepressants is highly specific, many patients require multiple trials before responding. It found that some subjects are non-responsive to all antidepressants, and some may relapse due to getting used to the drug. However, adjusting prostaglandins can induce both pro and anti-cancer actions. The constant presence of this paradox means that antidepressants may be capable of initiating or accelerating cancer and thus maintaining close clinical observation and limiting the duration of drug trials is essential.

The review also points out that epidemiological studies have failed to confirm the suspicion that antidepressants may induce breast cancer. However, breast cancer has been reported in three men taking selective serotonin reuptake inhibitors.

Dr Lieb added: “Wherever prostaglandin-synthesizing enzymes convert arachidonic acid to prostaglandins there are possible sites of action of antidepressants. By maintaining these enzymes within physiological limits, antidepressants shut down the mechanisms of carcinogenesis. Considerable evidence now shows that antidepressants are cytotoxic, cytostatic, convert multidrug resistant cells to sensitive, and protect nonmalignant cells from ionizing radiation and chemotherapy.

Antidepressants have potent pain relieving properties alone, or through enhancing narcotics, and they enhance sleep, appetite and occasionally energy. Their immuno-stimulating and antimicrobial properties may help with infection secondary to chemotherapy or radiation. Alleviation of anxiety, depression, fear of death, recrimination and remorse by antidepressants can be very beneficial, though care must be taken to monitor for negative effects such as intensification of depression or pain. Overall, the positive effects of antidepressants in cancer therapeutics far outweigh the negatives.”