Safinamide (Xadago) is the newest drug approved for Parkinson's disease. It is used as adjunct therapy to levodopa/carbidopa (Sinemet and others) when Parkinson's symptoms are not well controlled by that medication alone. Times when Parkinson's symptoms aren't being well controlled by treatment are referred to as "off episodes." Safinamide decreases the incidence of these episodes. The drug is not effective if used as monotherapy.
Safinamide is a monoamine oxidase type B (MAO-B) inhibitor. MAO inhibitors are used in the treatment of depression (likely because they increase serotonin levels), Parkinson's disease (likely because they increase available dopamine), and some other conditions. MAO-B inhibitors are believed to achieve their therapeutic effect by increasing the effect of levodopa/carbidopa, and ultimately raising levels of available dopamine.
Because it inhibits MAO, safinamide may cause any of the following: serotonin syndrome if used with other MAO inhibitors, antidepressants, or opioids; falling asleep during activities of daily living; hallucinations/psychotic behavior; problems with impulse control/compulsive behaviors; and retinal pathology (this precaution is based only on findings from animal studies). It may also cause or exacerbate dyskinesia and hypertension, and may produce withdrawal emergent hyperpyrexia and confusion.
Safinamide is contraindicated in patients with severe hepatic impairment (because concentrations of the drug will be increased), and dose limitations are required if moderate hepatic impairment is present. Other contraindications include use of other MAO inhibitors or potent inhibitors of MAO, which may cause hypertension or hypertensive crisis by increasing nonselective MAO inhibition; dextromethorphan, which may induce psychosis or abnormal behavior; opioids such as tramadol, meperidine, and related derivatives; certain antidepressants such as serotonin-norepinephrine reuptake inhibitors, tri- or tetracyclics, or triazolopyridines; cyclobenzaprine; methylphenidate, amphetamine, and their derivatives; and St. John's wort-all of these can induce life-threatening serotonin syndrome.
The most common adverse effects of safinamide are dyskinesia, falls, nausea, and insomnia. Some people experienced increased somnolence and fell asleep during normal daily activities.
Patient education should include information on potential risks, drug warnings, and common adverse effects. Although dietary tyramine restriction is not required with safinamide treatment (because of its MAO-B selectivity), eating large quantities of food high in tyramine increases the risk of hypertension. Nurses should teach patients to avoid more than 150 mg of aged, fermented, cured, smoked, and pickled foods. Because the tuberculosis drug isoniazid has some MAO inhibiting activity, patients may be at increased risk for interactions, including hypertension, if taking safinamide, isoniazid, and tyramine-containing foods. Nurses should also teach patients that safinamide might increase somnolence. If patients experience any new episodes of falling asleep during normal daily activities, they should avoid dangerous activities such as driving or operating machinery. Other sedating medications, alcohol, or central nervous system depressants may increase the risk of sedation. If dyskinesia occurs or worsens, NPs should consider decreasing the dose of levodopa/carbidopa.
To see complete prescribing information for safinamide, see http://bit.ly/2qJdwtw.