Q. I have Morton's neuroma (a swollen or thickened nerve in the ball of the foot), and the pain can be excruciating. I've tried gabapentin, which didn't really help, and two surgeries didn't help.

I would like to try Lyrica before going in for a third surgery, but my health plan won't pay for the medication. They say it has not been approved for Morton's neuroma. But the advertisements for Lyrica say it treats peripheral neuropathy (nerve pain away from the brain and spinal cord). So wouldn't it help the pain in my foot?

A. I'm sorry to disappoint you, but I've seen very little success with pregabalin (Lyrica) in the treatment of nerve pain. Moreover, pregabalin is so similar, chemically, to gabapentin that if one doesn't work I doubt the other will.

Sign up for the AARP Health Newsletter.

As you probably know, Morton's neuroma is an enlargement of the nerve that runs between the metatarsal bones in the foot. When the metatarsal bones press against the nerve, it can become inflamed, resulting in pain in the ball of the foot that often shoots into the toes.

Poorly fitting shoes are a prime cause of Morton's neuroma (which is 10 times more likely to affect women than men). My advice would be to seek out a specialist in custom orthotics, who can help fit you with better footwear. Shoes with low heels and wide toe boxes can significantly reduce the pain associated with Morton's neuroma. The specialist may also recommend for your shoes padded wedges that support the metatarsal arch and reduce the pressure on the nerve when you walk. Such custom orthotic devices can provide the support needed to reduce pressure and compression on the nerve.

If you continue to have neuropathic pain, you may wish to consult with your doctor or health professional about trying a low dose of an SSRI/SNRI — a newer-generation antidepressant. In the patients I see, 75mg to 150mg of venlafaxine ER (extended release) at bedtime has been very helpful in relieving neuropathic pain.

Antidepressants can relieve neuropathic pain in people who aren't depressed by blocking pain signals to the brain, and for that reason they're often the first-choice treatment. Be aware, though, that this is an "off label" use of these drugs — meaning that the Food and Drug Administration has not officially approved antidepressants for this use.

Ask the Pharmacist is written by Armon B. Neel Jr., PharmD, CGP, in collaboration with journalist Bill Hogan. They are coauthors of Are Your Prescriptions Killing You?, published in July by Atria Books.