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Selegiline should not be used at daily doses exceeding those recommended (10 mg/day) because of the risks associated with non-selective inhibition of MAO. (See CLINICAL PHARMACOLOGY.)
The selectivity of selegiline for MAO B may not be absolute even at the recommended daily dose of 10 mg a day. Rare cases of hypertensive reactions associated with ingestion of tyramine-containing foods have been reported in patients taking the recommended daily dose of selegiline. The selectivity is further diminished with increasing daily doses. The precise dose at which selegiline becomes a non-selective inhibitor of all MAO is unknown, but may be in the range of 30 to 40 mg a day.
Severe CNS toxicity associated with hyperpyrexia and death have been reported with the combination of tricyclic antidepressants and non-selective MAOIs (NARDIL, PARNATE ). A similar reaction has been reported for a patient on amitriptyline and ELDEPRYL (selegiline hcl) . Another patient receiving protriptyline and ELDEPRYL (selegiline hcl) developed tremors, agitation, and restlessness followed by unresponsiveness and death two weeks after ELDEPRYL (selegiline hcl) was added. Related adverse events including hypertension, syncope, asystole, diaphoresis, seizures, changes in behavioral and mental status, and muscular rigidity have also been reported in some patients receiving ELDEPRYL (selegiline hcl) and various tricyclic antidepressants.
Serious, sometimes fatal, reactions with signs and symptoms that may include hyperthermia, rigidity, myoclonus, autonomic instability with rapid fluctuations of the vital signs, and mental status changes that include extreme agitation progressing to delirium and coma have been reported with patients receiving a combination of fluoxetine hydrochloride (PROZAC) and nonselective MAOIs. Similar signs have been reported in some patients on the combination of ELDEPRYL (selegiline hcl) (10 mg a day) and selective serotonin reuptake inhibitors including fluoxetine, sertraline and paroxetine.
Since the mechanisms of these reactions are not fully understood, it seems prudent, in general, to avoid this combination of ELDEPRYL (selegiline hcl) and tricyclic antidepressants as well as ELDEPRYL (selegiline hcl) and selective serotonin reuptake inhibitors. At least 14 days should elapse between discontinuation of ELDEPRYL (selegiline hcl) and initiation of treatment with a tricyclic antidepressant or selective serotonin reuptake inhibitors. Because of the long half-lives of fluoxetine and its active metabolite, at least five weeks (perhaps longer, especially if fluoxetine has been prescribed chronically and/or at higher doses) should elapse between discontinuation of fluoxetine and initiation of treatment with ELDEPRYL (selegiline hcl) .
Some patients given selegiline may experience an exacerbation of levodopa associated side effects, presumably due to the increased amounts of dopamine reaction with super sensitive, post-synaptic receptors. These effects may often be mitigated by reducing the dose of levodopa/carbidopa by approximately 10 to 30%.
The decision to prescribe selegiline should take into consideration that the MAO system of enzymes is complex and incompletely understood and there is only a limited amount of carefully documented clinical experience with selegiline. Consequently, the full spectrum of possible responses to selegiline may not have been observed in pre-marketing evaluation of the drug. It is advisable, therefore, to observe patients closely for atypical responses.
Laboratory Tests: No specific laboratory tests are deemed essential for the management of patients on ELDEPRYL (selegiline hcl) . Periodic routine evaluation of all patients, however, is appropriate.
Carcinogenesis, Mutagenesis, and Impairment of Fertility
Assessment of the carcinogenic potential of selegiline in mice and rats is ongoing.
Selegiline did not induce mutations or chromosomal damage when tested in the bacterial mutation assay in Salmonella typhimurium and in an in vivo chromosomal aberration assay. While these studies provide some reassurance that selegiline is not mutagenic or clastogenic, they are not definitive because of methodological limitations. No definitive in vitro chromosomal aberration or in vitro mammalian gene mutation assays have been performed.
The effect of selegiline on fertility has not been adequately assessed.
Pregnancy Category C: No teratogenic effects were observed in a study of embryo-fetal development in Sprague-Dawley rats at oral doses of 4, 12, and 36 mg/kg or 4, 12 and 35 times the human therapeutic dose on a mg/m2 basis. No teratogenic effects were observed in a study of embryo-fetal development in New Zealand White rabbits at oral doses of 5, 25, and 50 mg/kg or 10, 48, and 95 times the human therapeutic dose on a mg/m2 basis; however, in this study, the number of litters produced at the two higher doses was less than recommended for assessing teratogenic potential. In the rat study, there was a decrease in fetal body weight at the highest dose tested. In the rabbit study, increases in total resorptions and % post-implantation loss, and a decrease in the number of live fetuses per dam occurred at the highest dose tested. In a peri- and postnatal development study in Sprague-Dawley rats (oral doses of 4, 16, and 64 mg/kg or 4, 15, and 62 times the human therapeutic dose on a mg/m2 basis), an increase in the number of stillbirths and decreases in the number of pups per dam, pup survival, and pup body weight (at birth and throughout the lactation period) were observed at the two highest doses. At the highest dose tested, no pups born alive survived to Day 4 postpartum. Postnatal development at the highest dose tested in dams could not be evaluated because of the lack of surviving pups. The reproductive performance of the untreated offspring was not assessed.
It is not known whether selegiline hydrochloride is excreted in human milk. Because many drugs are excreted in human milk, consideration should be given to discontinuing the use of all but absolutely essential drug treatments in nursing women.
The effects of selegiline hydrochloride in children have not been evaluated.
Last reviewed on RxList: 7/15/2008
This monograph has been modified to include the generic and brand name in many instances.
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