Fluvoxamine and Tizanidine interaction

Coadministration Coadministration of tizanidine, thioridazine, alosetron, or pimozide with Fluvoxamine Maleate Tablets is contraindicated [see Warnings and Precautions ( 5.4 , 5.5 , 5.6 , 5.7 )] .

Coadministration of tizanidine, thioridazine, alosteron, pimozide ( 4 )

Fluvoxamine and tizanidine should not be used together [see Contraindications ( 4 )] .

The effect of fluvoxamine (100 mg daily for 4 days) on the pharmacokinetics and pharmacodynamics of a single 4 mg dose of tizanidine has been studied in 10 healthy male subjects.

Tizanidine C max was increased approximately 12-fold (range 5-fold to 32-fold), elimination half-life was increased by almost 3-fold, and AUC increased 33-fold (range 14-fold to 103-fold).

Zanaflex is contraindicated in patients taking strong CYP1A2 inhibitors [see Drug Interactions ( 7.1 )] . with a history of hypersensitivity to tizanidine or the ingredients in Zanaflex.

Symptoms have included anaphylaxis and angioedema [see Warnings and Precautions ( 5.5 )] Concomitant use with strong CYP1A2 inhibitors ( 4 , 7.1 )

Therefore, concomitant use of Zanaflex with strong CYP1A2 inhibitors is contraindicated [see Contraindications ( 4 ) and Drug Interactions ( 7.1 )] .

Moderate or weak CYP1A2 inhibitors: avoid concomitant use; may cause hypotension, bradycardia, or excessive drowsiness; if concomitant use is necessary and adverse reactions occur, reduce Zanaflex dosage or discontinue.

Clinically significant hypotension (decreases in both systolic and diastolic pressure) has been reported with concomitant administration of tizanidine and strong CYP1A2 inhibitors [see Clinical Pharmacology ( 12.3 )] .