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[×] COMT inhibitors
 BRAND NAMES
 MECHANISM OF ACTION
Selegiline is a selective irreversible inhibitor of monoamine oxidase (MAO). MAO exists as two isoenzymes, referred to as MAO-A and MAO-B.
In humans, intestinal MAO is predominantly type-A, while most of that in the brain is type-B.
At the recommended dose, selegiline has greater affinity with type-B than for type-A active sites and serves as a selective inhibitor of MAO type-B (MAO-B).
In the CNS, MAO-B play important roles in the catabolism of dopamine, therefore, by inhibiting MAO-B, selegeline facilitates the activity of the nigrostriatal dopaminergic neuron.
Selegiline may have pharmacological effects unrelated to MAO-B inhibition. There is some evidence that it may increase dopaminergic activity by inhibiting dopamine reuptake at the synapse.
Selegiline (Oral) is indicated for the treatment of patients with Parkinson's disease. It can be used as monotherapy in the early phases of the disease and as adjunctive therapy with levodopa (with / without a peripheral decarboxylase inhibitor).
the recommended initial dose is 10mg/day. This may be taken either as one 10mg or two 5mg tablets. Selegiline can be taken as a single daily dose in the morning, or in two parts, half dose in the morning and half-dose at lunchtime. when taking selegiline in the evening or before going to bed the drug may lead to insomnia.
The recommended dose of (10 mg/day) should not be exceeded because of the risks associated with nonselective inhibition of MAO. MAO-A in the gastrointestinal tract, is thought to provide vital protection from exogenous amines (e.g. tyramine) that have the capacity, if absorbed intact, to cause a 'hypertensive crisis', the so-called 'cheese reaction'. The possibility of a hypertensive reaction at higher doses (>20 mg /day) of selegiline after ingestion of food or drugs rich in various exogenous amines has to be taken into account.
- Known hypersensitivity to selegiline
- If you have taken or are taking antidepressants known as selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine), paroxetine, or sertraline within the last five weeks.
- If you are taking antidepressants known as monoamine oxidase inhibitors (MAOIs) such as moclobemide, phenelzine or tranylcypromine or have taken these medications within the last two weeks.
- If you are taking antidepressants known as tricyclic antidepressants (TCAs) such as imipramine, clomipramine, amitriptyline or have taken these medications in the last two weeks.
 PREGNANCY AND LACTATION
 SIDE EFFECTS
In monotherapy, selegiline has been found to be well tolerated. Dry mouth, transient rise of serum alanine aminotransferase values and sleeping disorders have been reported more frequently than in patients receiving placebo.
Because selegiline potentiates the clinical efficacy of levodopa, the adverse reactions of levodopa, e.g. abnormal movements such as dyskinesias, nausea, agitation, confusion, hallucinations, headache, postural hypotension, cardiac arrhythmias and vertigo, may worsen when selegiline is added to the Maximum tolerated levodopa dose. Micturition difficulties and skin reactions have also been reported during selegiline treatment.
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