Pilocarpine Aids Saliva Flow, But Not via Changes to Gland Structure

Use of oral pilocarpine increased salivary flow in people with dry mouth due to primary Sjögren’s syndrome or other health conditions in a small study.

However, the medication did not significantly alter dental health or the structure of the salivary glands, as assessed via ultrasound.

The study, “Salivary Glands and Periodontal Changes in a Population of Sjögren’s and Sicca Syndrome Treated by Pilocarpine: A Pilot Study,” was published in Rheumatology and Therapy.

Xerostomia, the subjective feeling of mouth dryness, is characteristic of Sjögren’s syndrome. It can also occur due to other reasons, including diseases like diabetes, or as a result of medications or treatments like radiation therapy given to people with head and neck cancers.

Prior research has shown that pilocarpine can ease the feeling of dry mouth in people with primary Sjögren’s syndrome or other health conditions.

The effects of its use on the salivary glands has generally been assessed by measuring salivary flow, either stimulated, as in response to a food substance, or unstimulated.

Treatment has been shown to increase both stimulated and unstimulated salivary flow, but whether this is associated with changes to the structure of the salivary glands is not clear.

Researchers in France conducted a pilot study to determine whether three months of treatment with pilocarpine altered the structure of the salivary glands, as determined by ultrasound, in people with dry mouth.

Ultrasound uses sound waves to visualize structures within the body, such as the salivary glands. Conceptually, it works similar to the echolocation used by bats and dolphins — based on how sound waves bounce around in the body, a computer is able to create an image of internal structures.

A total of 19 female patients were enrolled in the study, and 11 completed it. Five patients discontinued treatment due to side-effects, one due to health insurance issues, one due to other health problems, and one did not come to the final clinical evaluation after three months.

Of these 11 women, five had Sjögren’s syndrome and the rest had xerostomia due to other reasons. Their mean age was 55.

Compared to rates measured at the study’s start, both stimulated and unstimulated salivary flow were significantly increased after three months on pilocarpine, in accordance with previous studies.

Salivary pH tended to be higher (less acidic and more basic) after treatment. However, the difference did not reach statistical significance, meaning that mathematically, there is a substantial probability that the difference was due to random chance.

No statistically significant changes were found in salivary gland structure, as assessed by ultrasound, after three months of pilocarpine treatment. Various measures of dental health also did not significantly change following treatment.

“This pilot study is the first attempt to set forth preliminary results about response to treatment by means of [salivary gland ultrasound]. Pilocarpine improved [stimulated and unstimulated salivary flow] measurements in our [dry mouth] population without any structural or vascular [ultrasound] changes,” the researchers concluded.

They noted several potential explanations for this finding. Most notably, this study was quite small, which makes it more difficult to detect a statistically significant change. The three-month treatment time was also relatively short.

The researchers suggested that larger studies with longer follow-up times may be warranted to better understand how pilocarpine impacts the salivary glands in people with dry mouth.