Drug Interaction Report

Iproniazid and Levodopa Oral Inhalation: Interaction Details

A pharmacist-reviewed analysis of the Iproniazid and Levodopa Oral Inhalation interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Levodopa Oral Inhalation

Inbrija Inbrija®
+

Iproniazid

No brand names on record
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Contraindicated
These should generally not be used together.
How we grade severity & evidence

Severity levels

  • Contraindicated: These should generally not be used together.
  • Major: Potentially serious — often needs a change or close monitoring.
  • Moderate: Can be significant — usually manageable with monitoring.
  • Minor: Usually limited clinical impact.

Evidence grades

  • Established: Well documented — supported by controlled studies or strong clinical data.
  • Probable: Good supporting evidence, though not definitively proven.
  • Suspected: Some evidence suggests this interaction, but it is not well established.
  • Possible: Limited or conflicting evidence; the interaction may occur.
  • Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Of 14 documented Iproniazid interactions, 7 are rated contraindicated — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
probable
Severity
Contraindicated

What happens

Hypertensive crisis

Interaction Deep Dive

Significant blood pressure elevations and hypertensive crisis have occurred during coadministration of carbidopa/levodopa with a nonselective MAOI271, such as iproniazid, and is contraindicated. Discontinue tranylcypromine at least 2 weeks prior to initiating treatment with carbidopa/levodopa 3546.

Why it happens (mechanism)

Increased dopamine and/or norepinephrine availability

Common questions

Can I take Iproniazid and Levodopa Oral Inhalation together?

Hypertensive crisis Always confirm with your pharmacist or prescriber before making any change.

How serious is the Iproniazid and Levodopa Oral Inhalation interaction?

It is rated contraindicated. These should generally not be used together.

How quickly could this interaction happen?

The documented onset is "unspecified". The timing of this interaction is not well characterized.

How strong is the evidence for this interaction?

The evidence is graded "probable". Good supporting evidence, though not definitively proven.

Questions for your pharmacist

  • Does my dose of Iproniazid or Levodopa Oral Inhalation need adjusting while I take them together?
  • What symptoms should prompt me to call you or my prescriber right away?
  • Does the timing of my doses matter for this combination?
  • Is there a safer alternative to one of these medications for me?

References (7)

  1. Hodge JV: Use of monoamine-oxidase inhibitors. Lancet 1965; 1:764. DOI
  2. Teychenne PF, Calne DB, Lewis PJ, et al: Interactions of levodopa with inhibitors of monoamine oxidase and l-aromatic amino acid decarboxylase. Clin Pharmacol Ther 1975; 18:273-277. PubMed
  3. Product Information: LODOSYN(R) oral tablets, carbidopa oral tablets. Valeant Pharmaceuticals North America LLC (per FDA), Bridgewater, NJ, 2014. DailyMed
  4. Product Information: SINEMET(R) oral tablets, carbidopa levodopa oral tablets. Merck Sharp & Dohme Corp. (per DailyMed), Whitehouse Station, NJ, 2013. DailyMed
  5. Product Information: SINEMET(R) CR oral sustained release tablets, carbidopa levodopa oral sustained release tablets. Merck Sharp & Dohme Corp. (per DailyMed), Whitehouse Station, NJ, 2013.
  6. Product Information: PARCOPA(R) oral disintegrating tablets, carbidopa levodopa oral disintegrating tablets. Azur Pharma, Inc. (per manufacturer), Philadelphia, PA, 2011. DailyMed
  7. Hunter KR, Boakes AJ, Laurence DR, et al: Monoamine oxidase inhibitors and L-dopa. Br Med J 1970; 3:388. PubMed
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Levodopa Oral Inhalation

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