New York, Oct 15 (IANS): Medical products derived from marijuana might have a mild benefit in treating symptoms of multiple sclerosis, a study has claimed.

Multiple sclerosis is a progressive and degenerative disease in which the immune system attacks nerves, producing a variety of neurological symptoms.

The findings, based on patient self-assessments from clinical trials, that cannabis-derived drugs can be considered safe and have limited effectiveness in treating multiple sclerosis symptoms.

Published in JAMA Network Open, it showed that drugs containing the major chemical compounds in cannabis are associated with a limited and mild reduction in muscle contractions, bladder dysfunction and pain, HealthDay reported.

"The bottom line is there is certainly something happening with cannabinoids in regard to symptoms," said Nicholas LaRocca, vice president of healthcare delivery and policy research at the National Multiple Sclerosis Society -- a US-based non-profit.

The clinical trials also showed that cannabis-derived drugs come with few side effects and no serious ones, the researchers said.

The review included clinical trials related to four cannabis-derived preparations: orally administered cannabis extract, nasally administered cannabis extract, and the drugs dronabinol and nabilone.

Dronabinol and nabilone are both synthetic versions of tetrahydrocannabinol (THC), the chemical in marijuana that causes intoxication. Both are used to treat nausea and vomiting caused by chemotherapy.

The new evidence review combined 17 clinical trials involving 3,161 patients. The team found that cannabis-derived drugs can be considered safe and have limited effectiveness in treating multiple sclerosis symptoms.

However, patients' self-reports of benefits related to muscle contractions differed from results of objective scales used by doctors. The doctors observed no such benefit from marijuana medications.

"That's something that's obviously a concern," LaRocca said.

Side effects associated with the drugs included dizziness, dry mouth, fatigue, intoxication, impaired balance, memory problems and sleepiness, the researchers said.