In a recent study published in Eye, researchers investigated the risk of angle-closure glaucoma (ACG) and open-angle glaucoma (OAG) in individuals taking attention-deficit/hyperactivity disorder (ADHD) medications.
Give me some background first.
ADHD is a common psychiatric condition with an estimated prevalence of 5% to 10% in children and 4% in adults in the U.S.
It is characterized by:
- Developmentally inappropriate hyperactivity
- Impulsivity
- Inattention
Now, talk about the study.
Researchers conducted a retrospective cohort study with a case-control analysis using data from the IQVIA PharMetrics Plus U.S. databases.
The cohort consisted of participants who were newly prescribed ADHD medications from 2010 to 2020. The participants were followed up until the first diagnosis of ACG or OAG, or the end of follow-up.
Note: A conditional logistic regression model was used to adjust for confounders and calculate adjusted incidence-rate-ratios (aIRRs).
Who was included in the study?
The study included 240,257 individuals comprised of:
- 1,159 glaucoma cases
- 4,636 controls
- 55% female
- Mean age: 45.4±19.4 years
What ADHD medications were participants using?
Of the participants:
- 15,830 (6.6%) were atomoxetine users
- 107,020 (44.5%) were amphetamines users
- 81,264 (33.8%) were methylphenidate users
- 36,143 (15.0%) used a combination of the above-mentioned medications
Findings?
The investigators found that:
- Mean follow-up time was 1.8 ± 1.7 years
- Regular users of atomoxetine and amphetamines had a higher aIRR for developing ACG compared with non-users
- aIRR = 2.55 95% Confidence interval (CI) (1.20–5.43) and 2.27 95% CI (1.42–3.63), respectively
- Users of methylphenidate had a higher aIRR for developing OAG
- aIRR = 1.23 95% CI (1.05–1.59)
So … what does this mean?
The investigators hypothesized that a potential reason why methylphenidate does not induce a higher risk of ACG compared to atomoxetine and amphetamines is due to the differences in the half-lives of the three medications.
The average half-lives of these medications were:
- Methylphenidate: 3.5 hours
- Atomoxetine: 5 hours
- Amphetamine: 11 hours
They explained that, “It may be possible that the longer the pupils are dilated, especially at night, the higher the chance of inducing ACG.”
Limitations?
Limitations included short follow-up time and a lack of dose-dependent analysis. The authors noted that they could not control for all potential confounders, including history of migraines.
Additionally, they stated that large, national databases can potentially suffer from non-standardized reporting practices. For the full list of limitations, refer to the study.
Expert opinion?
The authors stated that individuals taking ADHD medication may benefit from annual intraocular pressure (IOP) assessments and ophthalmologic assessments for suspicious ocular complaints.
They added that youth should be consulted regarding the potential for detrimental ocular side effects of the recreational use of ADHD medications.
Take home.
The use of amphetamines and atomoxetine was associated with a higher risk for ACG while methylphenidate use was associated with a higher risk for OAG.