Common Medications For ADHD Linked To Increased Risk Of Glaucoma
Authored by Marina Zhang via The Epoch Times (emphasis ours),
Common drugs prescribed to treat attention-deficit/hyperactivity disorder (ADHD) are associated with an increased risk of glaucoma, a recent Canadian study found.
Glaucoma is a progressive eye disease that causes vision loss. Angle-closure glaucoma is a subtype that contraindicates with popular ADHD drugs.
Dr. Rami Darwich, an ophthalmology resident and the study’s lead author, told The Epoch Times that the study “does not establish causation but rather highlights an elevated risk of glaucoma.”
Common ADHD Drugs
Many popular ADHD drugs are sympathomimetic drugs, meaning they activate the sympathetic nervous system to help people focus. However, their downstream effects can inadvertently contribute to elevated eye pressure.
High eye pressure is a significant risk factor for glaucoma, though Dr. Darwich added that some glaucoma has developed even without significant pressure changes in recent years.
Common ADHD drugs include sympathetic stimulants such as methylphenidate and amphetamines. These are often first-line treatments for people with ADHD due to their greater efficacy. Psychostimulants are effective for about 70 percent of ADHD patients.
Non-sympathomimetic drugs, such as atomoxetine, increase chemicals in the brain to help the brain work and concentrate. Atomoxetine is usually prescribed when the patient is unresponsive to first-line drugs.
The study authors followed 240,257 newly prescribed subjects who took either methylphenidate, amphetamines, atomoxetine, or a combination of these drugs for a year or more.
Study participants were then followed and compared to people who had not taken ADHD drugs to determine glaucoma risks.
People who took amphetamines and atomoxetine had a higher risk of angle-closure glaucoma (ACG), while people who took methylphenidate had a higher risk of open-angle glaucoma (OAG).
Our eyes are made up of fluids. Comparing a person’s eyes to a sink, Dr. Darwich explained that ACG occurs when “the drainage pipe of the sink gets blocked, causing the water (fluid inside your eye) to build up suddenly.”
With OAG, “the drainage pipe is open, but it’s like it’s clogged or narrow, so the water (fluid inside your eye) drains too slowly,” he said.
One might experience “severe eye pain, headache, and blurred vision” with ACG. “It can feel like there’s pressure building up in your eye.”
OAG is more chronic and doesn’t present with noticeable symptoms at first. Over time, blind spots can appear in the periphery, which can then progress to the center of one’s vision. However, much of the eye damage has already been done by that stage.
The authors also noted that atomoxetine and amphetamines were weakly linked to the development of OAG, though they said the correlation wasn’t statistically significant.
How ADHD Drugs Contribute to Glaucoma
The authors were surprised that methylphenidate was not strongly linked to ACG, which is contraindicated by psychostimulants that activate the nervous system.
In general, sympathomimetic drugs such as methylphenidate and amphetamines are not recommended for individuals with known or suspected ACG.
Since these medications activate the sympathetic nervous system—the system that prepares the body for fight or flight—the pupils dilate, which can mechanically obstruct the eye’s natural drainage pathway. This fluid buildup can increase eye pressure and damage the optic nerves, causing glaucoma and progressive vision loss.
OAG is more common than ACG, though it has a lower risk of vision loss, and its link to ADHD drugs is not well-established.
Methylphenidate, the drug shown to increase the risk of OAG, has also been found to be toxic to eye cells. The three medications studied have also been known to induce redox reactions, which may lead to oxidative damage, potentially impairing optical nerves and affecting eye health.
People whose bodies don’t properly metabolize ADHD drugs may also be at greater risk of drug-related glaucoma.
“Given the prevalence of ADHD medication use (medically and recreationally), further studies are needed to confirm our findings and investigate associations of ADHD medication use and glaucoma,” the authors wrote.