The combination of MAOIs and dextromethorphan has been reported to cause episodes of psychosis or bizarre behavior. Therefore, in view of XADAGO’s MAO inhibitory activity, dextromethorphan is contraindicated for use with XADAGO.
Severe hypertensive reactions have followed the administration of sympathomimetics and nonselective MAOIs. Hypertensive crisis has been reported in patients taking the recommended doses of selective MAO-B inhibitors and sympathomimetic medications. Concomitant use of XADAGO with methylphenidate, amphetamine, and their derivatives is contraindicated [see Warnings and Precautions (5.1, 5.2)].
Monitor patients for hypertension if XADAGO is prescribed concomitantly with prescription or nonprescription sympathomimetic medications, including nasal, oral, or ophthalmic decongestants and cold remedies [see Warnings and Precautions (5.1)].
MAO in the gastrointestinal tract and liver (primarily type A) provides protection from exogenous amines (e.g., tyramine). If tyramine were absorbed intact, it could lead to severe hypertension, including hypertensive crisis. Aged, fermented, cured, smoked, and pickled foods containing large amounts of exogenous amines (e.g., aged cheese, pickled herring) may cause release of norepinephrine resulting in a rise in blood pressure (Tyramine Reaction). Patients should be advised to avoid foods containing a large amount of tyramine while taking recommended doses of XADAGO [see Warnings and Precautions (5.1)].
Selectivity for inhibiting MAO-B decreases in a dose-related manner above the highest recommended daily dosage, which may increase the risk for hypertension [see Clinical Pharmacology (12.2)]. In addition, isoniazid has some monoamine oxidase inhibiting activity. Monitor for hypertension and reaction to dietary tyramine in patients treated with isoniazid and XADAGO [see Warnings and Precautions (5.1)].
Dopamine antagonists, such as antipsychotics or metoclopramide, may decrease the effectiveness of XADAGO and exacerbate the symptoms of PD.
There are no adequate data on the developmental risk associated with the use of XADAGO in pregnant women. In animals, developmental toxicity, including teratogenic effects, was observed when safinamide was administered during pregnancy at clinically relevant doses. Developmental toxicity was observed at doses lower than those used clinically when safinamide was administered during pregnancy in combination with levodopa/carbidopa.
The background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. 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.
In an embryofetal development study in rats, oral administration of safinamide (0, 50, 100, or 150 mg/kg/day) throughout organogenesis resulted in dose-related increases in fetal abnormalities (primarily urogenital malformations) at all doses. A no-effect dose for adverse effects on embryofetal development was not established. The lowest dose tested (50 mg/kg/day) is approximately 5 times the maximum recommended human dose (MRHD) of 100 mg on a body surface area (mg/m2) basis. In a combination embryofetal development study of safinamide and levodopa (LD)/carbidopa (CD) in rats (80/20 mg/kg/day LD/CD in combination with 0, 25, 50, or 100 mg/kg/day safinamide or 100 mg/kg/day safinamide alone), increased incidences of fetal visceral and skeletal malformations and variations were observed at all doses of safinamide in combination with CD/LD and with safinamide alone. The lowest dose of safinamide tested (25 mg/kg/day) is approximately 2 times the MRHD on a mg/m2 basis.
In embryofetal development studies in rabbits, no developmental toxicity was observed at up to the highest oral dose of safinamide tested (100 mg/kg/day). However, when safinamide (0, 4, 12, or 40 mg/kg/day) was administered throughout organogenesis in a combination study of safinamide with LD/CD (80/20 mg/kg/day LD/CD), there was an increased incidence of embryofetal death and cardiac and skeletal malformations, compared to LD/CD alone. A no-effect dose for safinamide was not established; the lowest effect dose of safinamide tested (4 mg/kg/day) is less than the MRHD on a mg/m2 basis.
In a rat pre- and postnatal development study, oral administration of safinamide (0, 4, 12.5, or 37.5 mg/kg/day) throughout pregnancy and lactation resulted in skin discoloration of the offspring, presumed to be due to hepatobiliary toxicity, at the mid and high doses and decreased body weight and increased postnatal mortality in offspring at the highest dose tested. The no-effect dose (4 mg/kg/day) for adverse developmental effects is less than the MRHD on a mg/m2 basis.
There is no information regarding the presence of XADAGO or its metabolites in human milk, the effects on the breastfed infant, or the effects on milk production.
The developmental and health benefits of breastfeeding should be considered along with the mothers’ clinical need for XADAGO and any potential adverse effects on the breastfed infant from XADAGO or from the underlying maternal condition.
Skin discoloration, presumed to be caused by hyperbilirubinemia resulting from hepatobiliary toxicity, was observed in rat pups indirectly exposed to safinamide through the milk during the lactation period.
Safety and effectiveness in pediatric patients have not been established.
Of the 1516 subjects exposed to XADAGO in clinical studies, 38% were 65 and over, while 4% were 75 and over. No overall differences in safety or effectiveness were observed between these patients and younger patients, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.
XADAGO plasma concentrations are increased in patients with hepatic impairment [see Clinical Pharmacology (12.3)].
In patients with moderate hepatic impairment (Child-Pugh B: 7-9), the maximum recommended dosage of XADAGO is 50 mg once daily [see Dosage and Administration (2.2)]. XADAGO has not been studied in patients with severe hepatic impairment (Child-Pugh C: 10-15), and is contraindicated in these patients. If patients progress from moderate to severe hepatic impairment, treatment with XADAGO should be stopped.
There is no human experience with XADAGO overdose.
There is no known antidote to XADAGO nor any specific treatment for XADAGO overdose. If an overdose occurs, XADAGO treatment should be discontinued and supportive treatment should be administered as clinically indicated. In cases of overdose with XADAGO, dietary tyramine restriction should be observed for several weeks.
The Poison Control Center should be called at 1-800-222-1222 for the most current treatment guidelines.
XADAGO tablets contain safinamide, which is a MAO-B inhibitor, as the mesylate salt. Safinamide mesylate is (S)-2- [[4-[(3-fluorophenyl) methoxy]phenyl]methyl]aminopropanamide methanesulfonate (1:1) and its structural formula is below.
The molecular formula of safinamide mesylate is C17 H19 FN2 O2 ∙CH4 O3 S and its molecular weight is 398.45.
Safinamide mesylate is a white to off-white crystalline powder. Safinamide mesylate is freely soluble in water, methanol and dimethyl sulfoxide. Safinamide mesylate is sparingly soluble in ethanol and is practically insoluble in ethyl acetate. In aqueous buffers that span a pH range of 1.2 to 7.5, safinamide mesylate is highly soluble at pH 1.2 and 4.5, but shows low solubility (<0.4 mg/mL) at pH 6.8 and 7.5.
XADAGO is available as 50 mg and 100 mg film-coated tablets for oral administration. Each XADAGO tablet contains 65.88 mg or 131.76 mg of safinamide mesylate, equivalent to 50 mg or 100 mg, respectively, of safinamide free base. The tablets also contain the following inactive ingredients: colloidal silicon dioxide, crospovidone, hypromellose, iron oxide (red), magnesium stearate, microcrystalline cellulose, polyethylene glycol 6000, potassium aluminum silicate, and titanium dioxide.
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