From the Guidelines
Adderall generally poses higher cardiovascular concerns than phentermine in adults, due to its more potent stimulant effects and stronger sympathetic nervous system activation. When comparing the cardiovascular risks of phentermine and Adderall in adults, it's essential to consider the mechanisms and effects of each medication. Phentermine, primarily used for short-term weight management, typically causes modest increases in heart rate and blood pressure, making it potentially safer for patients with controlled mild hypertension but still contraindicated in those with significant cardiovascular disease 1. In contrast, Adderall, an amphetamine combination used primarily for ADHD, has more potent stimulant effects that can cause more significant increases in heart rate, blood pressure, and cardiac workload, carrying black box warnings regarding serious cardiovascular events including sudden death, particularly in patients with pre-existing heart abnormalities. Key points to consider when prescribing either medication include:
- Avoiding use in patients with uncontrolled hypertension, advanced atherosclerosis, hyperthyroidism, glaucoma, or history of cardiovascular events
- Regular monitoring of vital signs
- Patients should report chest pain, palpitations, shortness of breath, or fainting immediately
- Phentermine should be used with caution in patients with well-controlled comorbidities, such as hypertension, dyslipidemia, and diabetes, as suggested by the AGA clinical practice guideline on pharmacological interventions for adults with obesity 1. Overall, while both medications carry cardiovascular risks, the more recent and higher quality study 1 suggests that Adderall poses a greater concern, and therefore, phentermine may be a safer option for patients with controlled mild hypertension, but careful consideration and monitoring are necessary to minimize cardiovascular risks.
From the Research
Comparative Cardiovascular Risks
The comparative cardiovascular risks of phentermine and Adderall in adults can be evaluated based on several studies:
- Phentermine has been associated with a reduced cardiovascular risk in overweight/obese patients at low-to-intermediate cardiovascular risk when used in combination with topiramate 2.
- Atrial fibrillation is a rare but potential cardiovascular side effect of phentermine, highlighting the need for clinician caution 3.
- Long-term phentermine pharmacotherapy for obesity has been shown to not increase blood pressure or heart rate, and may even be associated with favorable shifts in categorical blood pressure and retardation of progression to hypertension in obese patients 4.
Adderall Cardiovascular Risks
- The short-term cardiovascular effects of Adderall in youths with attention-deficit/hyperactivity disorder have been found to be modest, with no clinically significant changes in cardiovascular measures 5.
- There is limited direct evidence comparing the cardiovascular risks of phentermine and Adderall in adults.
Cardiovascular Safety
- A retrospective cohort study found that the rates of major adverse cardiovascular events (MACE) among current users of phentermine and topiramate were lower than those among unexposed former users, suggesting no increased risk of MACE for current users 6.
- However, the study also found that the rate of MACE among current users of topiramate alone was greater than among unexposed former users, highlighting the need for further research on the cardiovascular safety of these medications.
Key Findings
- Phentermine may be a safe and effective option for reducing weight in overweight/obese patients at low-to-intermediate cardiovascular risk 2, 4.
- Adderall has been found to have modest short-term cardiovascular effects in youths with attention-deficit/hyperactivity disorder 5.
- Further research is needed to fully understand the comparative cardiovascular risks of phentermine and Adderall in adults.