Mirtazapineinteractions

Table 5 includes clinically important drug interactions with mirtazapine. Table 5: Clinically Important Drug Interactions with Mirtazapine Monoamine Oxidase Inhibitors (MAOIs) Clinical Impact The concomitant use of serotonergic drugs, including mirtazapine, and MAOIs increases the risk of serotonin syndrome. Intervention Mirtazapine is contraindicated in patients taking MAOIs, including MAOIs such as linezolid or intravenous methylene blue. Examples selegiline, tranylcypromine, isocarboxazid, phenelzine, linezolid, methylene blue Other Serotonergic Drugs Clinical Impact The concomitant use of serotonergic drugs with mirtazapine increases the risk of serotonin syndrome. Intervention Monitor patients for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increases. If serotonin syndrome occurs, consider discontinuation of mirtazapine and/or concomitant serotonergic drugs. Examples SSRIs, SNRIs, triptans, tricyclic antidepressants, fentanyl, lithium, amphetamines, St. John’s Wort, tramadol, tryptophan, buspirone Strong CYP3A Inducers Clinical Impact The concomitant use of strong CYP3A inducers with mirtazapine decreases the plasma concentration of mirtazapine. Intervention Increase the dose of mirtazapine if needed with concomitant CYP3A inducer use. Conversely, a decrease in dosage of mirtazapine may be needed if the CYP3A inducer is discontinued. Examples phenytoin, carbamazepine, rifampin Strong CYP3A Inhibitors Clinical Impact The concomitant use of strong CYP3A inhibitors with mirtazapine may increase the plasma concentration of mirtazapine. Intervention Decrease the dose of mirtazapine if needed with concomitant strong CYP3A inhibitor use. Conversely, an increase in dosage of mirtazapine may be needed if the CYP3A inhibitor is discontinued. Examples itraconazole, ritonavir, nefazodone Cimetidine Clinical Impact The concomitant use of cimetidine, a CYP1A2, CYP2D6, and CYP3A inhibitor, with mirtazapine may increase the plasma concentration of mirtazapine. Intervention Decrease the dose of mirtazapine if needed with concomitant cimetidine use. Conversely, an increase in dosage of mirtazapine may be needed if cimetidine is discontinued. Benzodiazepines and Alcohol Clinical Impact The concomitant use of benzodiazepines or alcohol with mirtazapine increases the impairment of cognitive and motor skills produced by mirtazapine alone. Intervention Avoid concomitant use of benzodiazepines and alcohol with mirtazapine. Examples diazepam, alprazolam, alcohol Drugs that Prolong QTc Interval Clinical Impact The concomitant use of other drugs which prolong the QTc interval with mirtazapine, increase the risk of QTc prolongation and/or ventricular arrhythmias (e.g., Torsades de Pointes). Intervention Use caution when using mirtazapine concomitantly with drugs that prolong the QTc interval. Warfarin Clinical Impact The concomitant use of warfarin with mirtazapine may result in an increase in INR. Intervention Monitor INR during concomitant use of warfarin with mirtazapine.

Strong CYP3A inducers: Dosage increase may be needed for mirtazapine with concomitant use of strong CYP3A inducers.

Strong CYP3A inhibitors: Dosage decrease may be needed when mirtazapine is coadministered with strong CYP3A inhibitors.

Cimetidine: Dosage decrease may be needed when mirtazapine is coadministered with cimetidine.

Warfarin: Monitor INR during concomitant use.