ADHD Medication Adjustments

TLDR version: Immediate-release stimulants work better than extended release stimulants when taking a GLP-1 agonist. Immediate-release stimulants dose last longer when taking a GLP-1 agonist, but require a different dosing pattern than what works without a GLP-1 agonist.

(GLP-1 agonist are newer medications for weight loss and diabetes that were first available as injectables. I do not prescribe GLP-1 agonists, but I prescribe treatments for ADHD which may need to be adjusted because of the GLP-1 agonist use.)

More detail: GLP-1 agonists are reported to slow the speed at which the stomach empties its contents into the small intestine. Other reports indicate that stimulants are primarily absorbed in the small intestine.

When I was in residency, an older child psychiatrist told me that several extended-release formulations of methylphenidate had developed a reputation for not being effective. She felt like the timing of blood level increases affecting how well stimulants worked. Over the years I have heard this sentiment echoed by others in various ways. Pharmaceutical manufacturers learned the lesson and did a better job of testing newer formulations. For a while, it seemed like the problem had faded into history.

With widespread use of GLP-1 agonists, the problem has returned. I have only seen about 8 patients on both GLP-1 agonists and stimulants as of early April 2026, but the slower gastric emptying results in immediate release stimulants lasting longer and working more like an extended-release version, but with slightly different properties than existing extended-release formulations. It leads to the existing extended-release versions not working very well at all. Two patients of mine who took extended-release stimulants while on a GLP-1 agonist may have also seen increased development of tolerance to the stimulant effect.

Changes in the immediate-release dosing pattern are also needed for optimal results. Describing the pattern that I am seeing might be misconstrued as medical advice, so I am not going to go into detail here…but the trend I see emerging still needs adaptations tailored to the individual and to a lesser degree to the number of days past the last dose of GLP-1 agonist.