Muscle rigidity in Parkinson’s patients leveled off after regular use of laxatives for constipation, results of a new study published in the British Journal of Clinical Pharmacology showed.

Link to the gut

Researchers noted that the connection between constipation and Parkinson’s disease is well established, often predating diagnosis by decades. Also, diagnosed Parkinson’s patients often present with small intestinal bacterial overgrowth, with an increase in muscle rigidity corresponding to these inflammatory markers.

The findings of the current study support previous research showing that changes in the gut and gut microbe imbalance may affect aspects of Parkinson’s disease. They confirm the gastrointestinal link to Parkinson’s disease, which have implications for future symptom management and treatment.

“That the apparent effect of regular laxatives appeared in those who had never received drugs for Parkinson’s disease points to modification of an underlying disease process,” said Dr John Dobbs, co–lead researcher.

“Different aspects of Parkinson’s disease may, of course, have different drivers. For example, our controlled trial of eradicating Helicobacter from the stomach showed a beneficial effect on the diminished movement of Parkinson’s disease.”

The study

In this study, researchers investigated whether improving intestinal transit using laxatives can effectively slow the pace of observed increase in muscle rigidity.

Using specific inclusion criteria, they conducted a retrospective service evaluation of 79 patients who exhibited Parkinson’s symptoms and attended the same gut/brain axis clinic, where repeated measurements of muscle rigidity were conducted.

Overall, they analyzed 1,493 measurements over a total of 374 person-years. Results show that muscle rigidity increased by 6% per year prior to the introduction of laxative use. However, rigidity was shown to plateau at 2% per year thereafter.

These documented changes were also recognized over multiple laxative classes, pointing to a common mechanism.

Based on the findings and the established prevalence of constipation as a precursor to diagnosis, the researchers concluded that use of laxatives have clear early stage potential to combat rigidity in Parkinson’s patients.