Although the efficacy of gabapentin for insomnia has not been established, it does alleviate sleep disorder in patients with medical illness.Gabapentin does not appear to provide benefit for bipolar disorder, complex regional pain syndrome, post-surgical pain, or tinnitus, or prevent episodic migraine in adults. Contraindications
Gabapentin should be used carefully and at lower doses in people with kidney problems due to possible accumulation and toxicity. It is unclear if it is safe during pregnancy or breastfeeding. Side effects
Dizziness and somnolence are the most frequent side effects. Fatigue, ataxia, peripheral edema (swelling of extremities), and nystagmus are also common. Gabapentin is associated with a weight gain of 2.2 kg after 1.5 months of use. Case studies indicate that it may cause anorgasmia and erectile dysfunction, as well as myoclonus that disappear after discontinuing gabapentin or replacing it with other medication. DRESS, anaphylaxis, respiratory depression, and increased suicide behavior are the rare but serious side effects. Suicide
The gabapentin label contains a warning of an increased risk of suicidal thoughts and behaviors. According to an insurance claims database study, gabapentin use is associated with about 40% increased risk of suicide, suicide attempt and violent death as compared with a reference anticonvulsant drug topiramate. The risk is increased for both bipolar disorder and epilepsy patients. Another study has shown an approximately doubled rate of suicide attempts and self-harm in patients with bipolar disorder who are taking gabapentin versus those taking lithium.
Since August 2009, the U.S. FDA has required warnings to be placed on packaging with respect to increased risks of certain cancers.The risks involved seem to be related both to the duration and the dosage used. People who have previously been treated with an alkylating agent may have an excessive risk of cancers if treated with azathioprine. Epidemiological studies by International Agency for Research on Cancer have provided "sufficient" evidence of azathioprine carcinogenicity in humans (group 1), although the methodology of past studies and the possible underlying mechanisms are questioned.The various diseases requiring transplantation may in themselves increase the risks of non-Hodgkin lymphoma, squamous cell carcinomas of the skin, hepatobiliary carcinomas, and mesenchymal tumours to which azathioprine may add additional risks. Those receiving azathioprine for rheumatoid arthritis may have a lower risk than those undergoing transplantation.Cases of hepatosplenic T-cell lymphoma – a rare type of lymphoma – have been reported in patients treated with azathioprine. The majority occurred in patients with inflammatory bowel disease. Adolescents and young adult males were the majority of cases. They presented with a very aggressive disease course, and with one exception, died of the lymphoma. The FDA has required changes to the labeling to inform users and clinicians of the issue. Skin cancers
In transplant patients, skin cancer is 50 to 250 times more common than in the general population, and between 60 and 90% of patients are affected 20 years after transplantation.