Does Adipex (Phentermine) reduce hypotension?

From the Guidelines

Adipex (phentermine) does not reduce hypotension; in fact, it typically raises blood pressure as a side effect. Adipex is a stimulant medication primarily prescribed for short-term weight management in obese patients, working by suppressing appetite through its effects on the central nervous system. As a sympathomimetic amine similar to amphetamines, Adipex commonly causes increased heart rate and elevated blood pressure by stimulating the release of norepinephrine and other catecholamines 1.

Key Points to Consider

• Patients with hypertension, heart disease, or other cardiovascular conditions should use Adipex with caution or avoid it altogether, as it can exacerbate these conditions 1.
• The recommended dosage of phentermine is 15 to 37.5 mg orally once daily in the morning, and it should not be used with monoamine oxidase inhibitors or other sympathomimetic amines 1.
• If you have high blood pressure and need medication to lower it, you should consult with your healthcare provider about appropriate antihypertensive medications such as ACE inhibitors, ARBs, calcium channel blockers, or diuretics.
• Never use Adipex as a means to control blood pressure, as this could potentially worsen your cardiovascular health 1.

Important Considerations

• Phentermine is a Schedule IV medication and has a potential for abuse and dependence 1.
• The most common side effects of phentermine include dry mouth, difficulty sleeping, dizziness, and irritability, and it should be used with caution in patients with anxiety or insomnia 1.
• Appropriate candidates for phentermine include patients with obesity who need assistance with appetite suppression, but it should be used under the guidance of a healthcare provider and with careful monitoring of blood pressure and other cardiovascular parameters 1.

From the FDA Drug Label

7.4 Adrenergic Neuron Blocking Drugs Phentermine may decrease the hypotensive effect of adrenergic neuron blocking drugs.

Phentermine does not reduce hypotension, it may actually decrease the hypotensive effect of certain medications, potentially worsening hypotension. 2

From the Research

Effect of Adipex (Phentermine) on Hypotension

• The available evidence does not directly address the effect of Adipex (Phentermine) on hypotension, as the studies primarily focus on its impact on hypertension and weight loss 3, 4, 5, 6.
• However, several studies suggest that phentermine can lead to reductions in blood pressure, which may not be beneficial for individuals with hypotension 4, 5, 6.
• A study published in 2011 found that phentermine treatment for obesity did not result in increased systolic or diastolic blood pressure and was associated with favorable shifts in categorical blood pressure 4.
• Another study from 1983 reported significant reductions in blood pressure in patients treated with phentermine, which were likely related to weight loss rather than a direct effect of the drug 5.
• A 2016 review of long-term effects of weight-reducing drugs, including phentermine, found that phentermine/topiramate lowered blood pressure in people with elevated blood pressure 6.
• A case report from 2022 discussed the rare occurrence of atrial fibrillation associated with phentermine use, but did not address the effect of phentermine on hypotension 7.

Blood Pressure Effects

• The evidence suggests that phentermine can lead to reductions in blood pressure, particularly in individuals with hypertension 4, 5, 6.
• However, the effect of phentermine on hypotension is not well understood, and further research is needed to determine its safety and efficacy in individuals with low blood pressure.
• It is essential to consider the potential cardiovascular side effects of phentermine, including atrial fibrillation, and to rule out secondary causes of these effects, such as medication side effects 7.