Cyclobenzaprine extended-release

Based on its structural similarity to tricyclic antidepressants, cyclobenzaprine hydrochloride extended-release capsules may have life-threatening interactions with MAO inhibitors [see Contraindications ( 4 )], may enhance the effects of alcohol, barbiturates, and other CNS depressants, may enhance the seizure risk in patients taking tramadol, or may block the antihypertensive action of guanethidine and similarly acting compounds. Postmarketing cases of serotonin syndrome have been reported during combined use of cyclobenzaprine and other drugs, such as SSRIs, SNRIs, TCAs, tramadol, bupropion, meperidine, verapamil, or MAO inhibitors [see Warnings and Precautions ( 5.1 )].

MAO Inhibitors: Life-threatening interactions may occur ( 4 , 7 ) Serotonergic Drugs: Serotonin syndrome has been reported ( 5.1 , 7 ) CNS Depressants: Effects of alcohol, barbiturates, and other CNS depressants may be enhanced ( 5.2 , 7 ) Tramadol: Seizure risk may be enhanced ( 7 ) Guanethidine: Antihypertensive effect may be blocked ( 7 )

8.1 Pregnancy Risk Summary Available data from case reports with cyclobenzaprine hydrochloride extended-release capsules use in pregnancy have not identified a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. In rats, decreased pup body weight and survival was noted at cyclobenzaprine doses ≥10 mg/kg/day (approximately ≥3 times the maximum recommended human dose (MRHD) of 30 mg/day), when administered orally during pregnancy and lactation (see Data). The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown.

All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the US general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal Data No adverse embryofetal effects were reported following oral administration of cyclobenzaprine during organogenesis to mice and rabbits at maternal doses up to 20 mg/kg/day (approximately 3 and 15 times the MRHD, respectively, on a mg/m 2 basis). Maternal toxicity characterized by decreased body weight gain was observed only in mice at the highest tested dose of 20 mg/kg/day.

Decreased pup body weight and survival were reported in a prenatal and postnatal study where pregnant rats were treated orally with cyclobenzaprine during pregnancy and lactation with maternal doses of 10 and 20 mg/kg/day (approximately 3 and 6 times the MRHD on a mg/m 2 basis). Maternal toxicity, characterized by a decreased body weight gain, was observed only at the highest tested dose of 20 mg/kg/day.