If you need to take a pill, you might want to take it lying down -- on your right side, that is.
Researchers studying how body positioning affects the absorption of pills found that one taken when a person was lying on the right side speeded pills to the deepest part of the stomach. That pill could then dissolve 2.3 times faster than if the person was upright.
"We were very surprised that posture had such an immense effect on the dissolution rate of a pill," said senior author Rajat Mittal, a professor at Johns Hopkins Whiting School of Engineering and an expert in fluid dynamics. "I never thought about whether I was doing it right or wrong but now I'll definitely think about it every time I take a pill."
For the study, researchers used a model called StomachSim, which relies on physics, biomechanics and fluid mechanics to mimic what happens inside one's gut as it digests food or medicine.
Researchers knew that most pills don't start working until the stomach ejects its contents into the intestine. That would mean that a pill landing in the last part of the stomach, an area called the antrum, would begin dissolving faster. It would also begin emptying its contents more quickly through the pylorus into the duodenum, the first part of the small intestine.
To land a pill there would require a posture that uses both gravity and the natural asymmetry of the stomach to its benefit.
In addition to the right side, the team tested taking pills on the left side, standing upright and lying straight back.
Surprisingly, a pill that dissolves in 10 minutes with a patient lying on his or her right side could take 23 minutes to dissolve in an upright posture and more than 100 minutes with the person on his or her left side. Lying straight back tied with standing upright in terms of pill dissolution.
"For elderly, sedentary or bedridden people, whether they're turning to left or to the right can have a huge impact," Mittal said in a Hopkins news release.
Lead author Jae Ho "Mike" Lee, a former postdoctoral researcher at Johns Hopkins, noted that even small changes in stomach conditions could significantly affect dissolution -- when someone's gut isn't functioning at its best because of conditions such as diabetes and Parkinson's syndrome, for example.
The impacts of posture and stomach disease were similar on drug dissolution.
"Posture itself has such a huge impact … it's equivalent to somebody's stomach having a very significant dysfunction as far as pill dissolution is concerned," Mittal said.
Plans for future work include attempting to predict how changes in the biomechanics of the stomach affect how the body absorbs drugs.
The findings were recently published in the journal Physics of Fluids.
The U.S. National Institute on Aging has more about safe use of medicines for older adults.
SOURCE: Johns Hopkins University, news release, Aug. 15, 2022