Isoniazid and Phendimetrazine interaction

Isoniazid and Phendimetrazine: the Phendimetrazine prescribing label flags this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.

Major

Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.

What the FDA labels say

From the Phendimetrazine (PHENDIMETRAZINE TARTRATE) label · effective 2025-12-19

Major

…coronary artery disease, stroke, arrhythmias, congestive heart failure, uncontrolled hypertension, pulmonary hypertension) • During or within 14 days following the administration of monoamine oxidase inhibitors • Hyperthyroidism • Glaucoma • Agitated states • History of drug abuse • Pregnancy (see PRECAUTIONS, Pregnancy ) • Nursing • Use in combination with other…

Contraindicationsby drug classView label on DailyMed
Major

Drug Interactions Monoamine Oxidase Inhibitors Use of phendimetrazine tartrate is contraindicated during or within 14 days following the administration of monoamine oxidase inhibitors because of the risk of hypertensive crisis.

Drug interactionsby drug classView label on DailyMed
Moderate

Use of phendimetrazine tartrate within 14 days following the administration of monoamine oxidase inhibitors may result in a hypertensive crisis.

Warningsby drug classView label on DailyMed

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Not 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.