After at first being a skeptic I am finding a significant role for Lyrica in treatment of neuropathic pain syndromes. Lyrica first came to market in December of 2004 in the US with approval for diabetic neuropathic pain and post herpetic neuralgic pain. I was a slow adopter of this drug. It seemed essentially a high priced alternative to Neurontin, a closely related drug that is used off label for the same indications. It appeared another case of a drug company miraculously coming up with a new and improved version of an old drug shortly before the patent on the old drug expires as I’ve previously discussed with Nexium and Lexapro. (Pfizer markets gabapentin as Neurontin and also pregabalin as Lyrica) Lyrica is pregabalin which is chemically very similar to gabapentin and works by the same mechanism.
Over time I have come to realize that Lyrica does have some distinct advantages over gabapentin. From a practical standpoint the biggest advantage of Lyrica over gabapentin is that I can prescribe a dose of Lyrica that has a chance of working for their painful condition without intolerable Lyrica side effects at the starting dose. The lowest dose of gabapentin that is typically effective for neuropathic pain is 1800 mg daily. Starting a patient at that dose will almost always lead to intolerable drowsiness and an intoxicated sensation of disequilibrium and confusion. We have to start gabapentin with a slow taper up in dosing to avoid these intolerable side effects. A typical starting regimen would be to start on gabapentin 100 mg three times a day, or 300 mg at bedtime for a few days and then very gradually increase the dose over a couple of weeks or more to a dose of 600 mg three times daily. Most patients do not get adequate pain relief at doses much lower than 1800 mg daily of gabapentin. Increasing the dose much faster almost guarantees the patient stopping therapy due to these side effects. Using Lyrica I can prescribe 50-75 mg twice daily from the beginning with a good chance that the starting dose will help with the pain. If it takes a higher dose the Lyrica can be increased much faster than gabapentin without causing undue sedation and drugged feeling in most patients.
Other advantages of Lyrica over gabapentin include the faster and more consistent absorption from the gut. About 90% of Lyrica is absorbed from the gut vs. 27-60% of gabapentin being absorbed. In addition the absorption of Lyrica is not dose dependent whereas the higher the dose of gabapentin the lower the absorption rate. Both Lyrica and gabapentin work via a similar mechanism biologically.
For conditions like diabetic peripheral neuropathy I find gabapentin to be a good option. These patients have a chronic condition that has usually been slowly progressive, and gradually beginning a medication with the expectation of help over a few weeks time is acceptable to most of these patients. For more acutely painful conditions like herpes zoster and trigeminal neuralgia the idea of taking up to several weeks for pain relief is much less acceptable. In these conditions Lyrica is far more attractive.
Lyrica was also the first drug with an FDA approval specifically for treating fibromyalgia. Gabapentin is also used off label (without a specific FDA indication for the condition being treated) for fibromyalgia. It is nice as a physician to have a drug with a proven benefit for fibromyalgia as it is a notoriously difficult to treat problem. I have had a couple of patients who have had dramatic improvement of their fibromyalgia on Lyrica and have not had this type of response with gabapentin. I expect that once Lyrica loses its patent and becomes competitive with gabapentin as a generic medication it will nearly replace gabapentin as the drug of choice or treatment of neuropathic pain. For reasons unknown to me gabapentin has not come down dramatically in price like nearly every other generic drug. The cash price of gabapentin 300 mg capsules at Costco is still 14.68/ 100 capsules of the generic product, making the cost of 600 mg three times daily $26.42/ month. This compares favorably though to brand name Neurontin at $391.63 for the same dose or Lyrica 75 mg twice daily of $172.95 / month. My experience has also been that it is difficult to receive authorization from third party payers for Lyrica without previously trying gabapentin, even when gabapentin does not have FDA approval for the condition being treated.
In summary I still use generic gabapentin frequently, and find it a very good drug, but I find that Lyrica sometimes works when gabapentin seems not to be effective and that Lyrica is frequently better tolerated by patients. Especially for patients with fibromyalgia Lyrica is sometimes a remarkably effective drug when not much else seems to work.