Are ADHD Medications Linked to Increased Glaucoma Risk?

What you need to know

• Some common ADHD medications may increase the risk of developing certain types of glaucoma
• Amphetamines and atomoxetine were associated with higher risk of angle-closure glaucoma
• Methylphenidate was linked to increased risk of open-angle glaucoma
• Patients taking ADHD medications should get regular eye exams to monitor for glaucoma
• More research is needed to understand the mechanisms and confirm these potential risks

Background on ADHD and Medications

Attention deficit hyperactivity disorder (ADHD) is a common psychiatric condition that affects both children and adults. It is characterized by difficulty paying attention, hyperactivity, and impulsive behavior. ADHD is thought to be caused by differences in brain development and function, particularly related to the neurotransmitters dopamine and norepinephrine.

Several medications are used to treat ADHD, with the most common being:

• Stimulants like amphetamines (e.g. Adderall) and methylphenidate (e.g. Ritalin)
• Non-stimulants like atomoxetine (Strattera)

These medications work by increasing levels of dopamine and norepinephrine in the brain, which helps improve focus and reduce hyperactivity in people with ADHD. While effective for many patients, there are concerns about potential side effects and risks associated with long-term use of these drugs.

One area of concern is the potential impact on eye health, particularly the risk of developing glaucoma. Glaucoma is a group of eye conditions that damage the optic nerve, often due to abnormally high pressure inside the eye. It can lead to vision loss if not detected and treated early.

The Current Study

Researchers conducted a large study to examine whether common ADHD medications are associated with increased risk of developing glaucoma. They analyzed health insurance claims data for over 240,000 people who were newly prescribed ADHD medications between 2010-2018.

The study looked at two main types of glaucoma:

1. Angle-closure glaucoma (ACG) - where the drainage angle in the eye becomes blocked
2. Open-angle glaucoma (OAG) - where the drainage angle is open but fluid drains too slowly

They compared the rates of glaucoma diagnosis between people taking different ADHD medications and those not taking any.

Key Findings

The study found some concerning links between certain ADHD medications and glaucoma risk:

Angle-closure glaucoma:

• Atomoxetine users had 2.55 times higher risk
• Amphetamine users had 2.27 times higher risk
• No significant increase for methylphenidate users

Open-angle glaucoma:

• Methylphenidate users had 1.23 times higher risk
• No significant increase for atomoxetine or amphetamine users

These increased risks were found for “regular users” who had filled at least one prescription every 3 months in the year before their glaucoma diagnosis.

Possible Explanations

The researchers propose a few potential reasons for these findings:

For angle-closure glaucoma:

• The medications can dilate (widen) the pupils, which may increase risk in people predisposed to ACG
• Longer-acting drugs like atomoxetine and amphetamines may pose more risk than shorter-acting methylphenidate

For open-angle glaucoma:

• The medications may affect the balance of oxidative stress in cells
• This could potentially damage the trabecular meshwork (the eye’s drainage system) over time

However, the exact mechanisms are not yet clear and require further research to confirm.

Implications for Patients and Doctors

These findings have important implications for people taking ADHD medications and the doctors who prescribe them:

1. Regular eye exams: Patients on ADHD medications should have annual eye pressure checks and comprehensive eye exams to monitor for early signs of glaucoma.

2. Awareness of symptoms: Both patients and doctors should be alert for potential glaucoma symptoms like eye pain, blurred vision, or seeing halos around lights.

3. Careful prescribing: Doctors may need to consider glaucoma risk factors when choosing ADHD medications, especially for patients with a family history of glaucoma.

4. Monitoring long-term use: The risks of these medications may increase with prolonged use, so ongoing monitoring is important.

5. Patient education: People taking ADHD medications should be informed about the potential risk of glaucoma so they can report any concerning eye symptoms promptly.

Limitations and Future Research

While this study provides valuable insights, it does have some limitations:

• It was based on insurance claims data, which may not capture all relevant information
• The follow-up period was relatively short (average 1.8 years)
• It didn’t examine how medication dosage might affect risk

Future research is needed to:

• Confirm these findings in other populations
• Investigate the underlying biological mechanisms
• Determine if the risk varies based on medication dose or duration of use
• Explore whether certain patients are at higher risk than others

Conclusions

• Use of amphetamines and atomoxetine was associated with higher risk of angle-closure glaucoma
• Methylphenidate use was linked to increased risk of open-angle glaucoma
• Patients taking ADHD medications should have regular eye exams to monitor for glaucoma
• Doctors should consider potential glaucoma risk when prescribing ADHD medications
• More research is needed to fully understand the relationship between ADHD medications and glaucoma risk

This study highlights the importance of ongoing safety monitoring for widely-used medications. While ADHD medications are beneficial for many patients, understanding potential risks allows for more informed decision-making and appropriate monitoring to protect long-term health.