Mirtazapine and Nirmatrelvir and ritonavir interaction

Mirtazapine and Nirmatrelvir and ritonavir: both prescribing labels flag 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 Nirmatrelvir and ritonavir (Paxlovid) label · effective 2026-02-19

Major

…(selective blocker of Na v 1.8 sodium channels): suzetrigine • Opioid antagonists: naloxegol • PDE5 inhibitor: sildenafil (Revatio ® ) when used for pulmonary arterial hypertension (PAH) • Sedative/hypnotics: triazolam, oral midazolam • Serotonin receptor 1A agonist/serotonin receptor 2A antagonist: flibanserin • Vasopressin receptor antagonists: tolvaptan ➢ Drugs that…

Contraindicationsby drug classView label on DailyMed
Major

Sedative/hypnotics triazolam, oral midazolam ↑ triazolam ↑ midazolam Co-administration contraindicated due to potential for extreme sedation and respiratory depression [see Contraindications (4) ] .

Drug interactionsby drug classView label on DailyMed
Major

Serotonin receptor 1A agonist/ serotonin receptor 2A antagonist flibanserin ↑ flibanserin Co-administration contraindicated due to potential for hypotension, syncope, and CNS depression [see Contraindications (4) ] .

Drug interactionsby drug classView label on DailyMed
Moderate

Antidepressants bupropion ↓ bupropion and active metabolite hydroxy-bupropion Monitor for an adequate clinical response to bupropion. trazodone ↑ trazodone Adverse reactions of nausea, dizziness, hypotension, and syncope have been observed following co-administration of trazodone and ritonavir.

Drug interactionsby drug classView label on DailyMed
Moderate

Sedative/hypnotics buspirone, clorazepate, diazepam, estazolam, flurazepam, zolpidem ↑ sedative/hypnotic A dose decrease may be needed for these drugs when co-administered with PAXLOVID and monitoring for adverse events. midazolam (administered parenterally) ↑ midazolam Co-administration of midazolam (parenteral) should be done in a setting which ensures close…

Drug interactionsby drug classView label on DailyMed

From the Mirtazapine (REMERONSOLTAB) label · effective 2025-08-06

Moderate

Examples phenytoin, carbamazepine, rifampin Strong CYP3A Inhibitors Clinical Impact The concomitant use of strong CYP3A inhibitors with REMERON/REMERONSolTab may increase the plasma concentration of mirtazapine [see Clinical Pharmacology (12.3) ] .

Drug interactionsby drug classView label on DailyMed
Moderate

Intervention Decrease the dose of REMERON/REMERONSolTab if needed with concomitant strong CYP3A inhibitor use.

Drug interactionsby drug classView label on DailyMed
Moderate

Conversely, an increase in dosage of REMERON/REMERONSolTab may be needed if the CYP3A inhibitor is discontinued [see Dosage and Administration (2.5) ].

Drug interactionsby drug classView label on DailyMed
Moderate

Examples itraconazole, ritonavir, nefazodone Cimetidine Clinical Impact The concomitant use of cimetidine, a CYP1A2, CYP2D6, and CYP3A inhibitor, with REMERON/REMERONSolTab may increase the plasma concentration of mirtazapine [see Clinical Pharmacology (12.3) ].

Drug interactionsby drug classView label on DailyMed
Moderate

Strong CYP3A inhibitors : Dosage decrease may be needed when REMERON/REMERONSolTab is coadministered with strong CYP3A inhibitors.

Drug interactionsby 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.