Dextroamphetamine and Phentermine interaction
Dextroamphetamine and Phentermine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Dextroamphetamine (Dextroamphetamine Sulfate Extended-Release) label · effective 2023-12-31
CONTRAINDICATIONS Advanced arteriosclerosis, symptomatic cardiovascular disease, moderate to severe hypertension, hyperthyroidism, known hypersensitivity or idiosyncrasy to the sympathomimetic amines, glaucoma.
Hypersensitivity reactions such as angioedema and anaphylactic reactions have been reported in patients treated with other amphetamine products [see Adverse Reactions ].
…alone carry an increased risk of sudden death, stimulant products generally should not be used in children or adolescents with known serious structural cardiac abnormalities, cardiomyopathy, serious heart rhythm abnormalities, or other serious cardiac problems that may place them at increased vulnerability to the sympathomimetic effects of a stimulant drug.
Hypertension and Other Cardiovascular Conditions Stimulant medications cause a modest increase in average blood pressure (about 2 mmHg to 4 mmHg) and average heart rate (about 3 bpm to 6 bpm), and individuals may have larger increases.
Tricyclic Antidepressants May enhance the activity of tricyclic or sympathomimetic agents causing striking and sustained increases in the concentration of d-amphetamine in the brain; cardiovascular effects can be potentiated.
From the Phentermine (Phentermine hydrochloride) label · effective 2026-08-17
Risk of Abuse and Dependence Phentermine is related chemically and pharmacologically to amphetamine (d- and d l l-amphetamine) and other related stimulant drugs that have been extensively abused.
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.