Subsequent to the corporate acquisition of the original patent holder, the pharmaceutical company Pfizer admitted that there had been violations of FDA guidelines regarding the promotion of unproven off-label uses for gabapentin in the Franklin v. Parke-Davis case (see below). Reuters reported on 25 March 2010, that "Pfizer Inc violated federal racketeering law by improperly promoting the epilepsy drug Neurontin ... Under federal RICO law the penalty is automatically tripled, so the finding will cost Pfizer $141 million." The case stems from a claim from Kaiser Foundation Health Plan Inc. that "it was misled into believing Neurontin was effective for off-label treatment of migraines, bipolar disorder and other conditions. Pfizer argued that Kaiser physicians still recommend the drug for those uses", and that "the insurers website also still lists Neurontin as a drug for neuropathic pain. "The Wall Street Journal noted that Pfizer spokesman Christopher Loder said, "We are disappointed with the verdict and will pursue post-trial motions and an appeal." He later added that "the verdict and the judges rulings are not consistent with the facts and the law." Franklin v. Parke-Davis case
While off-label prescriptions are common for a number of drugs, marketing of off-label uses of a drug is not. In 2004, Warner-Lambert (which subsequently was acquired by Pfizer) agreed to plead guilty for activities of its Parke-Davis subsidiary, and to pay $430 million in fines to settle civil and criminal charges regarding the marketing of Neurontin for off-label purposes.
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.