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What the FDA labels say about taking them together

Dihydroergotamine and ritonavir

Dihydroergotamine's FDA label of March 6, 2025 names ritonavir in its contraindications section, and ritonavir's label names dihydroergotamine too. The ritonavir label: “Contraindicated due to potential for acute ergot toxicity characterized by vasospasm and ischemia of the extremities and other tissues including the central nervous system.”

Check it at the source: the dihydroergotamine FDA label on DailyMed (effective March 6, 2025, Oceanside Pharmaceuticals); the ritonavir FDA label on DailyMed (effective July 23, 2026, AbbVie Inc.).

What does the dihydroergotamine label say about ritonavir?

Dihydroergotamine label, contraindications

The use of potent CYP 3A4 inhibitors (ritonavir, nelfinavir, indinavir, erythromycin, clarithromycin, troleandomycin, ketoconazole, itraconazole) with dihydroergotamine is, therefore contraindicated ( see WARNINGS, CYP 3A4 Inhibitors ).

Dihydroergotamine label, warnings

The use of potent CYP 3A4 inhibitors with dihydroergotamine should therefore be avoided ( see CONTRAINDICATIONS ). Examples of some of the more potent CYP 3A4 inhibitors include: antifungals ketoconazole and itraconazole, the protease inhibitors ritonavir, nelfinavir, and indinavir, and macrolide antibiotics erythromycin, clarithromycin, and troleandomycin.

Trudhesa label (Impel Pharmaceuticals LLC, September 3, 2026), contraindications

CONTRAINDICATIONS TRUDHESA is contraindicated in patients: with concomitant use of strong CYP3A4 inhibitors, such as protease inhibitors (e.g., ritonavir, nelfinavir, or indinavir), macrolide antibiotics (e.g., erythromycin or clarithromycin), and antifungals (ketoconazole or itraconazole) [see Warnings and Precautions (5.1) and Drug Interactions (7.1) ] with ischemic heart disease (angina pectoris, history of myocardial infarction, or documented silent ischemia) or patients who have clinical symptoms or findings consistent with coronary artery vasospasm, including Prinzmetal's variant angina [see Warnings and Precautions (5.4) ] with uncontrolled hypertension [see Warnings and Precautions …

Trudhesa label (Impel Pharmaceuticals LLC, September 3, 2026), drug interactions

There have been rare reports of serious adverse events in connection with the coadministration of intravenous administration of dihydroergotamine and strong CYP3A4 inhibitors, such as protease inhibitors (e.g., ritonavir, nelfinavir, indinavir), macrolide antibiotics (e.g., erythromycin, clarithromycin), and antifungals (e.g., ketoconazole, itraconazole), resulting in vasospasm that led to cerebral ischemia and/or ischemia of the extremities [see Warnings and Precautions (5.1) ].

Source: FDA drug label (Trudhesa, NDA213436), Impel Pharmaceuticals LLC, effective September 3, 2026 (SPL set b81397b0-910d-4eb4-8fee-a9a3c9d94d63), via openFDA

Source: FDA drug label (Dihydroergotamine Mesylate), NDA020148 (Bausch), as published by Oceanside Pharmaceuticals, effective March 6, 2025 (SPL set 977de209-c53a-4cb4-9f3f-1e850600a9dc), via openFDA; the full label on DailyMed

What does the ritonavir label say about dihydroergotamine?

Ritonavir label, contraindications

NORVIR is contraindicated with drugs that are highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening reactions [see Drug Interactions ( 7.1 ) and Clinical Pharmacology ( 12.3 )]. ○ Alpha 1- Adrenoreceptor Antagonist: alfuzosin ○ Antianginal: ranolazine ○ Antiarrhythmics: amiodarone, dronedarone, flecainide, propafenone, quinidine ○ Antifungal: voriconazole ○ Anti-gout: colchicine ○ Antipsychotics: lurasidone, pimozide ○ Ergot Derivatives: dihydroergotamine, ergotamine, methylergonovine ○ GI Motility Agent: cisapride ○ HMG-CoA Reductase Inhibitors: lovastatin, simvastatin ○ Microsomal triglyceride transfer …

Ritonavir label, drug interactions

Concomitant Drug Class/Drug Name: Ergot Derivatives: dihydroergotamine, ergotamine, methylergonovine; Effect on Concentration of Ritonavir or Concomitant Drug: ↑ ergot derivatives; Clinical Comment: Contraindicated due to potential for acute ergot toxicity characterized by vasospasm and ischemia of the extremities and other tissues including the central nervous system [see Contraindications () ].

Source: FDA drug label (Norvir), AbbVie Inc., effective July 23, 2026 (SPL set 2849298e-de6e-47bb-8194-56e075b33fc3), via openFDA; the full label on DailyMed

These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.

Both medicines on the record

9Dihydroergotamine generic labelers
7Ritonavir generic labelers
DihydroergotamineRitonavir
Labeled forMigraineHIV
Boxed warningYesYes
Pharmacy cost (NADAC)$29.44 per mL 4 mg/mL nasal spray$0.607 per tablet 100 mg tablet
Shortage nowNo current entryA presentation being discontinued

Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)

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