When Greg Yudkowsky, 15, hit 185 pounds, his mother, Michelle, knew it was time to do something. Although the 5-foot-6-inch teen, who has Duchenne muscular dystrophy, still was walking with assistance and full leg braces, the extra weight made moving more difficult, and the family struggled to lift him. His physical therapist said that losing even 10 pounds would help.

Greg, of Agoura Hills, Calif., tried limiting his calories to 800 to 900 a day. But the strict diet was hard to follow and his weight climbed to 196. Michelle, who holds a doctorate in neuroscience, began intensively researching the issue and pressing Greg’s pediatrician to do the same.

Enter Topamax. The drug (generic name: topiramate) was developed for seizure control. One of its notable side effects is weight loss.

Greg’s doctor agreed to give the drug a try. “It was a shot in the dark,” Michelle Yudkowsky says. “There’s no track record with patients like Greg.”

Under medical supervision, Greg started out taking 25 milligrams of Topamax per day. As the dosage increased, his hunger vanished and the pounds started to come off —  20 pounds in the first three months, 42 pounds in seven months.

MDA clinic director Greg Carter of  Seattle has used both Topamax and Wellbutrin (bupropion, an antidepressant with a possible weight loss side effect) to help some patients with neuromuscular diseases reduce their appetites and lose weight.

The drugs “must be used with extreme caution and close physician supervision because they have other significant side effects as well,” Carter warns. Topamax carries a risk of kidney stones, raised blood acidity, dizziness, nausea, headaches, fatigue and mental fuzziness. Up to 15 percent of users can experience troublesome cognitive, emotional or physical side effects. Wellbutrin can cause (among other things) seizures, insomnia and mania.

Some patients with NMDs have lost so much weight on Topamax that it became painful to sit in a wheelchair due to loss of padding.

The ideal candidate, Carter says, would have no history of drug intolerance and be in good health, with no significant heart disease. Carter doubts these drugs would be effective against prednisone-induced weight gain, which is due to the direct effect of the steroid on protein metabolism and fluid retention.

Greg Yudkowsky has managed to avoid kidney stones by drinking low-calorie cranberry juice, and blood tests show no evidence of blood acidity, which can weaken bones and impair growth. Greg adjusted the Topamax dose when he became more tired than usual while exercising.

Greg’s determination and adherence to his diet have been “incredible,” his mother says. He feels satisfied eating 800 to 850 calories a day (supplemented with multivitamins), still walks with help and exercises with a pulley weight daily. Once he hits the normal weight range for his height, he’ll either be weaned off the drug or kept on a low maintenance dose.

While thankful that Topamax worked for Greg, Michelle also feels frustrated that weight gain in kids with DMD isn’t taken more seriously. She notes that parents may have to take the lead in seeking safe, healthy weight solutions that work for their children.