Two drugs may enhance recovery from stroke

When a person has a stroke caused by a blood clot, doctors immediately prescribe powerful drugs to dissolve the clot and restore blood flow to starved brain tissues. This can save the patient’s life, but if part of the brain has been damaged, stroke survivors often face difficulties speaking or moving their limbs.

Studies in Germany and the United States now indicate that two drugs not currently prescribed for stroke–the anti-Parkinson’s disease medication levodopa and a stimulant called dextroamphetamine–can help restore function in the damaged parts of the brain. If tests in larger numbers of people support these findings, the drugs could improve poststroke therapy, which has been largely limited to speech training and physical therapy.

The brain converts levodopa into dopamine and, in turn, norepinephrine; both these chemicals relay signals between cells in the brain. In people with Parkinson’s disease, levodopa offsets a shortage of dopamine.

In the Sept. 8 Lancet, Klaus Scheidtmann of the Neurology Clinic in Bad Aibling, Germany, and his colleagues describe giving 22 stroke patients levodopa and 25 others inert pills daily for 3 weeks. Treatment started 3 weeks to 6 months after a patient’s stroke. Unaware of which patients received medication or placebo until after the 6-week trial, the scientists provided the doses one-half hour before a physical therapy session. All but 12 of the patients were wheelchair-bound at the start, and only one in each group could walk unassisted, Scheidtmann says.

After the 6 weeks, 11 of the patients who had received levodopa, or 50 percent, were able to walk, compared with 7 of those getting placebo, or 28 percent.

In the other study, researchers in Texas and California gave 12 stroke patients dextroamphetamine pills starting on average 1 month after their stroke. Nine other stroke patients with similar language impairments received a placebo. Patients received 10 doses of dextroamphetamine or the placebo just before speech and language therapy over 5 weeks. Earlier work had shown that such mild doses of amphetamines can spur norepinephrine production.

After only 1 week of treatment, the group receiving dextroamphetamine but not the placebo group demonstrated significant speech improvement. A week after treatment ended, both groups had improved, says study coauthor Delaina Walker-Batson, a neuroscientist at Texas Woman’s University in Dallas.

By that time, two of the nine patients getting the placebo improved by at least 15 points on a 100-point scale for speech and language ability.

However, 10 of the 12 patients treated with dextroamphetamine had improved

that much, the researchers report in the September Stroke.

Scientists consider a 15-point improvement to be significant, says Walker-Batson. She and her colleagues used a test that measures four basic language components–speaking, listening, reading, and writing.

Repeated use helps the brain recover, Walker-Batson says. This study suggests that dextroamphetamine may speed that process, she says.

Test-tube and animal studies have indicated that release of norepinephrine within the brain can stimulate neurons to take on new tasks and compensate for damaged tissues. However, norepinephrine given directly causes harsh side effects.

The studies of levodopa and dextroamphetamine “are very interesting and encouraging, and are consistent with other studies,” says Larry B. Goldstein, a neurologist at Duke University Medical Center in Durham, N.C.