Saturday, December 20, 2008

Newer Drugs Not Worth Noting, cont.

Neurontin (gabapentin)

Neurontin is one of the least useful drugs in history, and the subject of one of the sorriest scandals in modern pharmaceutical history. A brief history, via Wikipedia:

Gabapentin is best known under the brand name Neurontin manufactured by Pfizer subsidiary Parke-Davis. A Pfizer subsidiary named Greenstone markets generic gabapentin. In December 2004, the FDA granted final approval to a generic equivalent to Neurontin made by Israeli firm Teva.

Neurontin is one of Pfizer’s best-selling drugs, and was one of the 50 most-prescribed drugs in the United States in 2003. However, in recent years, Pfizer has come under heavy criticism for its marketing of Neurontin, facing allegations that, behind the scenes, Parke-Davis marketed the drug for at least a dozen supposed uses for which the drug had not been FDA approved.

By some estimates, so-called off-label prescriptions account for roughly 90% of Neurontin sales. While off-label prescriptions are common for a number of drugs and are perfectly legal (if not always appropriate), marketing of off-label uses of a drug is strictly illegal. In 2004, Warner-Lambert agreed to plead guilty and pay $430 million in fines to settle civil and criminal charges regarding the illegal marketing of Neurontin for off-label purposes, and further legal action is pending. The courts of New York State, for example, have refused to certify a class of injured parties who took Neurontin for off-label use, finding that they had failed to state that they had any injury.

The University of California, San Francisco (UCSF) has archived and studied the documents made public by this case, which opens a unique window into pharmaceutical marketing and their illegal promotion. However, Pfizer maintains that the illegal activity originated in 1996, well before it acquired Parke-Davis (through its acquisition of Warner-Lambert) in 2000. Several lawsuits are underway after people prescribed gabapentin for off-label treatment of bipolar disorder attempted or committed suicide.

In fact, Neurontin was very heavily marketed (illegally) to psychiatrists (including this author) by its manufacturer as a new treatment for Bipolar Disorder, with no evidence to support its use. At one point, Neurontin was probably the single most commonly prescribed drug for Bipolar Disorder, and its use was widespread for many other off-label indications. Eventually, FDA pressure led the company to do some actual research, which showed that Neurontin was slightly less effective than placebo in treating Bipolar Disorder! So why did anyone ever prescribe this dud? Because it’s so well tolerated (again, from Wikipedia):

Gabapentin's most common side effects in adult patients include dizziness, drowsiness, and peripheral edema (swelling of extremities); these mainly occur at higher doses, in the elderly. Also, children 3–12 years of age were observed to be susceptible to mild-to-moderate mood swings, hostility, concentration problems, and hyperactivity. Although rare, there are several cases of hepatotoxicity reported in the literature.

Clinical experience in fragile X shows gabapentin to be rather ineffective in its primary indication (epilepsy) and entirely useless as a psychiatric treatment. Indeed, most fragile X patients treated with Neurontin exhibit markedly worse behavior. This typically manifests as behavioral disinhibition---decreased impulse control, defiant and unruly behavior, etc. Aggression, irritability, and mood lability (already a problem!) usually get much worse when Neurontin is introduced. Now, to be fair, gabapentin probably does have some role in the treatment of certain chronic pain conditions---it’s not complete garbage---but it is not a useful psychotropic, period.

As a litmus test for psychopharmacologists, you could not do better than simply asking how much Neurontin that doctor has used (this author has never written a single prescription or recommended it to any patient---ever.) Any psychiatrist who still uses this medication is not worth seeing; if any doctor recommends Neurontin to you or a family member for a psychiatric purpose, run away and don’t look back. (You may have noticed that I feel strongly about this; the misrepresentation of Neurontin by Big Pharma and the wholesale, unthinking acceptance of a worthless drug by the psychiatric profession represent embarrassing low points for both.)