Influence of anti-anxiety medication on gastric emptying studies

Objectives: Among contraindications for gastric emptying studies are medications that can complicate the interpretation of results. Anti-anxiety medications are not among these, yet there is evidence that pts may have some abnormal microbial biota that produce both abnormal gastric symptoms & anxiety or depression (J Affect Disord. 2017;208:22-32). Therefore, the objective of our investigation was to determine if there were relationships between anti-anxiety medication & gastric emptying.

Methods: Data were examined for 164 pts (age = 47±18 years; 116 female; 48 male) referred for evaluation of gastric symptoms who underwent gastric motility studies. No patient had diabetes. Pt charts were reviewed to determine whether they were on anti-anxiety medication at the time of the test. The imaging protocol for liquid emptying involved dynamic imaging of the stomach region for 30 min following ingestion of 7.4 MBq ¹¹¹In-DTPA in 10 mL water immediately followed by 300 cc water, & computing the T_1/2 of liquid gastric emptying. To evaluate solid gastric emptying, pts ingested a standardized meal consisting of 4 ounces of egg whites labeled with 37 MBq ^99mTc-sulfur colloid, along with 2 pieces of bread & 4 grams of jam. Simultaneous 1-min anterior & posterior static images were collected with pts erect. Attenuation-corrected conjugate view counts were determined within manually drawn regions over the stomach, & per cent retention values recorded at 1-hr intervals for 4 hrs. The criteria for an abnormal liquid emptying study was T_1/2 > 20 min, & for a solid emptying study > 10% gastric retention at 4 hrs.

Results: 37/164 pts (23%) were on anti-anxiety medication at the time of the test. 92 (56%) pts had normal liquid & solid gastric emptying studies. 29 (18%) pts had abnormal liquid & solid gastric emptying studies, 58 (35%) pts had abnormal liquid gastric emptying studies, & 44 (26%) had abnormal solid gastric emptying studies. 29 (18%) pts had abnormal liquid & normal solid, while 15 (9%) pts had abnormal solid & normal liquid. There was a significant tendency of pts with abnormal liquid emptying to also have abnormal solid emptying (χ² = 22.7, p < 0.0001). Significantly fewer pts had abnormal liquid emptying who were on medication than those who were not (14% versus 42%, p = 0.001), with more rapid emptying time (18±18 versus 25±25 min, p = 0.04). There was a significant tendency of pts on medication to have both liquid & solid normal emptying results (χ² = 9.0, p = 0.003), & significantly more pts on medication had both liquid & solid normal emptying results than pts not on these medications (78% versus 48%, p = 0.001).

Conclusions: Our results suggest that anti-anxiety medications may accelerate gastric emptying in some pts who are referred for motility studies. If confirmed in a larger series of pts, then it could be advisable to take these medications into account in the interpretation of study results.