Are Amphetamines Safe for Older Adults with ADHD?

What you need to know

• Amphetamine use in adults over 65 with ADHD was associated with a 6 times higher risk of cardiovascular events compared to those not taking amphetamines.
• The increased risk included heart failure, stroke, irregular heart rhythms, and other heart problems.
• More research is needed to understand the risks and benefits of amphetamines in older adults, as most safety data comes from studies in younger people.

Background on ADHD and amphetamine use

Attention-deficit/hyperactivity disorder (ADHD) is a condition that affects both children and adults, causing symptoms like inattention, hyperactivity, and impulsivity. While ADHD is often thought of as a childhood disorder, many people continue to experience symptoms into adulthood and even later in life.

Amphetamines are a type of stimulant medication commonly prescribed to treat ADHD. They work by increasing levels of certain brain chemicals like dopamine and norepinephrine. This helps improve focus, reduce impulsivity, and manage other ADHD symptoms. Common amphetamine medications include Adderall, Vyvanse, and Dexedrine.

In recent years, there has been a significant increase in amphetamine prescriptions for older adults. One study found a 355% increase in stimulant prescriptions for adults over 65 between 2008 and 2018. However, there has been limited research on the safety and risks of these medications specifically in older populations.

Why study amphetamine use in older adults?

As people age, their bodies go through many changes that can affect how medications work and what side effects they may cause. Some key changes that occur in the cardiovascular system with aging include:

• Decreased elasticity of blood vessels
• Changes in the electrical system of the heart
• Higher levels of stress hormones like adrenaline circulating in the body
• Buildup of plaque in arteries (atherosclerosis)

These natural aging processes mean that older adults may be more vulnerable to cardiovascular side effects from medications. Amphetamines are known to increase heart rate and blood pressure, which could potentially be riskier for older individuals with age-related changes to their heart and blood vessels.

Most of the safety data on amphetamines comes from studies in children, adolescents, and younger adults. There is a need for more research to understand if the risks may be different for people over 65. This study aimed to look specifically at cardiovascular risks associated with amphetamine use in older adults with ADHD.

How the study was conducted

The researchers used a large database of electronic health records from 43 healthcare organizations in the United States. They identified patients over 65 years old who had been diagnosed with ADHD.

The study compared two groups:

1. Patients prescribed amphetamines (4,966 people)
2. Patients not prescribed amphetamines (4,966 people)

To make the comparison as fair as possible, the researchers used a technique called propensity score matching. This helped ensure the two groups were similar in terms of factors like age, sex, race/ethnicity, body mass index, and other health conditions that could affect cardiovascular risk.

They then looked at how many people in each group experienced cardiovascular events over a 3-year period from 2018 to 2020. The cardiovascular events they tracked included:

• Heart failure
• Heart attack
• Stroke
• Irregular heart rhythms (arrhythmias)
• Atrial fibrillation (a specific type of irregular heart rhythm)

The researchers also compared some biological measures between the two groups, including cholesterol levels, blood pressure, and hemoglobin A1c (a measure of blood sugar control).

Key findings on cardiovascular risks

The study found that older adults with ADHD who were prescribed amphetamines had significantly higher odds of experiencing cardiovascular events compared to those not taking amphetamines:

• Overall, the amphetamine group had 6.16 times higher odds of having a cardiovascular event
• This translated to 38 cardiovascular events per 1,000 people in the amphetamine group, compared to only 6 events per 1,000 in the control group
• The increased risk was seen across different types of cardiovascular events:
  • 3.5 times higher odds of heart failure
  • 2.5 times higher odds of stroke
  • 7.09 times higher odds of ischemic heart disease (reduced blood flow to the heart)
  • 6.9 times higher odds of arrhythmias
  • 4.4 times higher odds of atrial fibrillation

It’s important to note that the absolute risk was still relatively low in both groups. However, the large difference in risk between those taking and not taking amphetamines is concerning and warrants further investigation.

Blood pressure and cholesterol findings

The researchers also compared some biological measures that are often used to estimate cardiovascular risk. They found:

• Slightly higher systolic and diastolic blood pressure in the amphetamine group
• Slightly higher HDL (“good”) cholesterol in the amphetamine group
• No significant difference in LDL (“bad”) cholesterol or hemoglobin A1c levels

While the differences in blood pressure and HDL cholesterol were statistically significant, they were relatively small and may not be clinically meaningful on their own. However, even small increases in blood pressure can raise cardiovascular risk over time, especially in older adults.

Limitations and need for further research

This study provides important initial data on potential cardiovascular risks of amphetamine use in older adults with ADHD. However, there are some limitations to keep in mind:

• The study only looked at patients with diagnosed ADHD, so the findings may not apply to amphetamine use for other conditions.
• It did not account for the dose or duration of amphetamine use, which could affect risk.
• There may have been some errors in diagnosis codes or misclassification of patients.
• The study could not prove that amphetamines directly caused the increased cardiovascular events, only that there was an association.

More research is needed to:

• Confirm these findings in other populations of older adults
• Understand how the dose and duration of amphetamine use affects risk
• Identify which subgroups of older adults may be at highest risk
• Explore the balance of potential benefits and risks for treating ADHD in older adults

Implications for patients and healthcare providers

This study raises important questions about the safety of amphetamine use in older adults with ADHD. While amphetamines can be effective for managing ADHD symptoms, the potential increased cardiovascular risk needs to be carefully considered.

The American Geriatrics Society already lists stimulants like amphetamines on their Beers Criteria as medications to avoid in older adults due to safety concerns. This new data provides further support for caution when considering amphetamine use in people over 65.

For patients:

• If you are over 65 and taking amphetamines for ADHD, don’t stop your medication without talking to your doctor.
• Discuss the potential risks and benefits with your healthcare provider.
• Make sure your blood pressure and heart health are being monitored regularly.
• Report any concerning symptoms like chest pain, shortness of breath, or irregular heartbeats to your doctor promptly.

For healthcare providers:

• Carefully weigh the potential risks and benefits when considering amphetamine prescriptions for older adults with ADHD.
• Explore non-stimulant options for managing ADHD symptoms in this age group when possible.
• Monitor cardiovascular health closely in older patients taking amphetamines, including regular blood pressure checks.
• Be aware that safety data from younger populations may not apply to older adults.

Conclusions

• This study found a significantly increased risk of cardiovascular events in adults over 65 taking amphetamines for ADHD compared to those not taking these medications.
• The absolute risk was still relatively low, but the large difference between groups is concerning.
• More research is needed to understand the risks and benefits of amphetamine use in older adults with ADHD.
• Patients and healthcare providers should carefully consider the potential cardiovascular risks when making decisions about ADHD treatment in older adults.
• Close monitoring of cardiovascular health is important for older adults taking amphetamines.

While effective ADHD treatment is important at any age, this study highlights the need for caution and careful consideration of risks and benefits when prescribing amphetamines to older adults. As our population ages, more research focused specifically on medication safety in older age groups will be crucial to inform clinical decision-making and improve patient care.