ADHD medications Adderall, Concerta and Ritalin.. (Photo by PureRadiancePhoto on Shutterstock)
New research brings awareness to potential heart problems linked to non-stimulant prescription drugs for the condition.
In a nutshell
- Contrary to popular belief, non-stimulant ADHD medications (atomoxetine and viloxazine) affect heart rate and blood pressure just as much as stimulants do.
- All ADHD medications except guanfacine increase blood pressure and heart rate by similar amounts – about 1-2 points for blood pressure and 3-6 extra heartbeats per minute.
- Guanfacine stands alone in actually lowering blood pressure and heart rate, with especially strong effects in adults, making it potentially beneficial for ADHD patients with high blood pressure.
SOUTHAMPTON, England — Parents and adults dealing with ADHD often hear warnings about medication side effects: “Keep an eye on heart rate.” “Check blood pressure regularly.” But exactly which drugs affect the cardiovascular system most? Do stimulants really pose greater risks than non-stimulants?
New research published in The Lancet: Psychiatry tackles these questions head-on, examining data from more than 100 clinical trials with over 22,000 participants. What the international team of researchers found turns common assumptions upside down—particularly about which ADHD medications actually impact heart function and blood pressure.
Doctors have long warned patients that stimulant medications like Adderall (amphetamine) and Ritalin (methylphenidate) could bump up blood pressure and quicken heart rate. Meanwhile, newer non-stimulant options have flown somewhat under the radar regarding heart concerns. This fresh study reveals something unexpected: non-stimulant medications such as atomoxetine (Strattera) and viloxazine (Qelbree) affect heart measures about as much as stimulants do—challenging what many doctors and patients believed.
The researchers put it plainly in their paper, provided to StudyFinds in a pre-published manuscript: practitioners should monitor blood pressure and heart rate in patients with ADHD treated with any pharmacological intervention, and not stimulants only.
The ADHD Medication Landscape: More Than Just Stimulants
ADHD touches roughly 5% of kids worldwide and sticks around into adulthood for up to half of them. Kids and adults with ADHD struggle with focus problems, excessive movement, acting without thinking, or some mix of these issues that interfere with daily life.
Pills and capsules remain key players in controlling ADHD symptoms, with various options approved by health authorities. The medicine cabinet includes several types:
- Stimulants: Amphetamines (Adderall), lisdexamfetamine (Vyvanse), and methylphenidate (Ritalin, Concerta)
- Noradrenaline boosters: Atomoxetine (Strattera) and viloxazine (Qelbree)
- Alpha-2 drugs: Clonidine (Kapvay) and guanfacine (Intuniv)
Most stimulants and some non-stimulants crank up norepinephrine (noradrenaline) signals in the brain—improving focus but potentially affecting heart function. Alpha-2 drugs like guanfacine do the opposite by turning down norepinephrine activity. This explains why they affected heart rates and blood pressure differently in the study.
Medical Sleuthing at Its Finest
Researchers from Brazil’s University of São Paulo and the UK’s University of Southampton led what scientists call a “network meta-analysis”—a fancy way of saying they compared treatments that haven’t all been tested against each other directly.
Their detective work involved scanning 12 databases to find 101 proper randomized controlled trials covering over 22,000 people. About 60% of studies looked at kids and teens (13,315 youngsters), while the rest focused on adults (8,942 grown-ups). Boy-heavy participation dominated the younger studies (73% male), while adult studies were more balanced (57% male).
The team monitored:
- Top blood pressure number (systolic)
- Bottom blood pressure number (diastolic)
- How fast hearts beat (pulse rate)
- Heart rhythm patterns (ECG measurements)
Most people in these studies were only followed for about 7 weeks—not long enough to see what might happen years down the road. The researchers ranked how confident they were in each finding using a system called CINeMA, with ratings from “high” (very sure) to “very low” (take with a grain of salt).
Surprising Heart Effects: Breaking Down the Numbers
Perhaps the biggest surprise in the study is that stimulants don’t stand alone in affecting heart function. In fact, five different medications showed remarkably similar effects on blood pressure and heart rate:
- Amphetamines (Adderall)
- Lisdexamfetamine (Vyvanse)
- Methylphenidate (Ritalin, Concerta)
- Atomoxetine (Strattera)
- Viloxazine (Qelbree)
For kids and teens, these drugs pushed up the top blood pressure number by about 1-2 points, the bottom number by 2-2.5 points, and added 3-5.5 extra heartbeats per minute compared to sugar pills.
Adults saw similar or slightly bigger changes: 1.6-2.3 points higher for top blood pressure, 1.6-3.1 points for bottom blood pressure, and 4.4-5.8 extra heartbeats each minute.
These numbers might look small on paper, but they’re just averages. Some people’s bodies react much more strongly—potentially causing problems for folks who already have high blood pressure or heart concerns.
When researchers directly compared medications, they found something that challenges conventional wisdom: stimulants didn’t raise blood pressure or heart rate any more than non-stimulants like atomoxetine or viloxazine. This runs contrary to the common belief that stimulants are riskier for the heart.
It’s also noteworthy that stimulants generally work better against ADHD symptoms than these non-stimulants do, hinting that stimulants must do something beyond just adjusting norepinephrine levels in the brain.
Against the Grain: Guanfacine Stands Alone in Reducing Blood Pressure
One medication marched to its own drummer: guanfacine (Intuniv) actually lowered blood pressure and slowed heart rate. Kids and teens taking guanfacine saw their top blood pressure number drop by about 2.8 points, bottom number fall by 2.1 points, and heart beat about 4.1 fewer times per minute compared to dummy pills.
The effects were even more dramatic in adults: top blood pressure plummeted 10.1 points, bottom number sank 7.7 points, and hearts slowed by nearly 7 beats per minute.
This opposite reaction makes perfect sense given how guanfacine works—it dampens norepinephrine signals rather than amplifying them. For ADHD patients who also struggle with high blood pressure, guanfacine could kill two birds with one stone. The downside? It generally doesn’t control ADHD symptoms as well as stimulants do, especially in adults.
What This Means for Patients and Doctors
For doctors, the message couldn’t be clearer: check blood pressure and pulse in everyone taking ADHD medication—not just stimulant users. For patients with heart problems who need ADHD treatment, guanfacine might be worth considering since it actually lowers blood pressure and slows heartbeats, though it typically doesn’t control ADHD symptoms as well as stimulants.
The researchers want to see new long-term studies tracking heart effects of these medications and suggest that cracking ADHD’s biological code might someday lead to treatments that don’t mess with the cardiovascular system.
Bottom line? Your heart doesn’t particularly care whether you’re taking a stimulant or a non-stimulant for your ADHD—but you and your doctor should. Regular blood pressure checks and pulse measurements matter for everyone taking these medications, regardless of which pill bottle sits in your medicine cabinet.
Paper Summary
Methodology
This research team conducted what’s called a “network meta-analysis,” which is essentially a super-powered comparison of multiple treatments. They searched 12 different medical databases to find every relevant clinical trial comparing ADHD medications. To be included, studies needed to be randomized controlled trials (where participants are randomly assigned to different treatments) involving people with ADHD aged 5 or older. The researchers focused on nine medications: amphetamines, atomoxetine, bupropion, clonidine, guanfacine, lisdexamfetamine, methylphenidate, modafinil, and viloxazine. They extracted data on blood pressure, heart rate, and ECG measurements from each study, then used sophisticated statistical methods to compare all medications against each other, even when they hadn’t been directly compared in the original trials. The team also evaluated how confident they could be in each finding based on factors like how many studies provided data and how consistent the results were.
Results
The analysis revealed that most ADHD medications increased blood pressure and heart rate compared to placebo pills. In children and adolescents, stimulants (amphetamines, lisdexamfetamine, and methylphenidate) and certain non-stimulants (atomoxetine and viloxazine) increased systolic blood pressure by 1-2 mmHg, diastolic blood pressure by 2-2.5 mmHg, and pulse by 3-5.5 beats per minute. Adults showed similar or slightly larger increases. Importantly, when comparing these medications directly against each other, stimulants didn’t cause statistically larger increases than non-stimulants like atomoxetine or viloxazine. Guanfacine was the exception, actually decreasing blood pressure and heart rate in both age groups, with particularly pronounced effects in adults (systolic BP: -10.1 mmHg, diastolic BP: -7.7 mmHg, pulse: -6.8 bpm). For ECG parameters, the findings generally aligned with the heart rate changes, with some medications shortening the PR interval or QRS complex duration, while atomoxetine slightly prolonged the QTc interval in adults.
Limitations
Despite analyzing data from 101 trials with over 22,000 participants, this study had several limitations. First, most trials were short (median 7 weeks), so the research couldn’t address long-term cardiovascular effects of ADHD medications. Second, the analysis couldn’t identify whether certain subgroups (like people with family history of heart disease) might experience larger cardiovascular effects than others. Third, the researchers didn’t examine differences across medication doses, though some evidence suggests higher doses might cause greater cardiovascular effects. Fourth, for some medications (particularly clonidine), data were limited, reducing confidence in the findings. Finally, the analysis focused on average effects across groups of patients, but individual responses can vary considerably—some people might experience much larger increases in blood pressure or heart rate than the average values reported.
Funding and Disclosures
The research was funded by the National Institute for Health and Care Research (NIHR) in the UK. Several authors reported potential conflicts of interest, including receiving research funding, consultation fees, or speaking honoraria from pharmaceutical companies. Dr. Samuele Cortese, one of the lead researchers, is funded as an NIHR Research Professor and supported by several NIHR grants and European Research Executive Agency funding. Dr. Henrik Larsson reported receiving grants from Shire Pharmaceuticals and fees from Medice, Shire/Takeda Pharmaceuticals, and Evolan Pharma AB. Other researchers reported funding from various sources including the University Hospital Toulouse, CARIPLO Foundation, Lundbeck, Angelini Pharma, and the Swedish Research Council. The authors noted that these relationships were outside the scope of the current work.
Publication Information
This study, titled “Comparative cardiovascular safety of medications for attention-deficit/hyperactivity disorder in children, adolescents, and adults: a systematic review and network meta-analysis,” was published in The Lancet: Psychiatry. It was conducted by an international team led by researchers from the University of São Paulo in Brazil and the University of Southampton in the UK. The manuscript was provided to StudyFinds in its pre-publication form, dated April, 11, 2024. The research was pre-registered in PROSPERO (number CRD42021295352), an international database of prospectively registered systematic reviews. The authors made their dataset and analysis codes freely available online in the Open Science Framework database.
