Selegiline: uses and side effects of this drug.

An MAOI-type Antidepressant used mainly in patients with Parkinson's disease.

Parkinson's disease is a type of movement disorder that originates when neurons do not produce enough dopamine, thus causing different movement impairments. For its treatment it is mainly used selegiline, an MAOI antidepressant..

In this article we will see how this drug works, as well as its characteristics, adverse effects and the possibility of combining it with other drugs.

Selegiline: general characteristics

Selegiline is an MAOI (selective MAO inhibitor) type antidepressant, specifically inhibits the degradation of MAO-B (dopamine degrading enzymes). That is, it acts by increasing the concentration of dopamine (a natural substance necessary to control movements) in the brain, which leads to improvements in the patient's motor function.

On the other hand, selegiline has a hypothetical neuroprotective effect due to its ability to inhibit the formation of free radicals from dopamine metabolism. from dopamine metabolism and, in addition, a mild symptomatic effect. It is of little use in the elderly since it produces confusion and nervousness.

Selegiline is administered orally (it should be swallowed with water and without chewing).

Mechanism of action

The mechanism of action of selegiline is the selective inhibition in the brain of MAO-B; MAO-B is an enzyme that catalyzes the oxidation of monoamines and the degradation of neurotransmitters -amines, in this case, degrades dopamine.

In other words, selegiline acts by increasing the concentration of dopamine in the brain.It is indicated in the nigrostriatal brain segments, specifically in the nigrostriatal brain segments, and as a consequence improves motor function (that is why it is indicated in Parkinson's disease).

Therapeutic indications

Selegiline is indicated for idiopathic Parkinson's disease.. It can be used as monotherapy in early stages of Parkinson's disease, or as an adjuvant to levodopa (with or without decarboxylase inhibitors). For its part, levodopa (L-DOPA) is the metabolic precursor of dopamine, and is considered the most effective single drug in the treatment of Parkinson's disease.

Thus, as we have seen, selegiline is used in conjunction with levodopa, and also with carbidopa (Sinemet).

Selegiline may help people with Parkinson's disease by decreasing the dose of levodopa/carbidopa needed to control symptoms, lengthening the effect of levodopa/carbidopa and thus increasing the length of time that levodopa/carbidopa will control symptoms.

Currently selegiline is now commonly used in conjunction with another MAOI, rasagilineas an adjuvant in cases of advanced Parkinson's disease to treat motor symptoms.

Contraindications

Selegiline is contraindicated when there is hypersensitivity to it; also concomitantly with: SSRIs (as it can trigger hypertensive crises), dual serotonin and noradrenaline reuptake inhibitors, tricyclic antidepressants, sympathomimetics, MAOIs and opioids.

In addition, the administration of selegiline should be avoided. during the 5 weeks following the last fluoxetine administration..

It is also contraindicated in cases of duodenal ulcer and/or gastric ulcer, as well as combination therapy with levodopa in: AHT, hyperthyroidism, pheochromocytoma, narrow-angle glaucoma, prostatic adenoma with residual urine appearance, tachycardia, arrhythmias, severe angina pectoris, psychosis, and advanced dementia.

Precautions

There are a number of concerns we should be aware of regarding selegiline. On the one hand, when combining selegiline treatment to the maximum tolerable dose of levodopa, involuntary movements and agitation may occur..

If this occurs, the levodopa dose can be reduced by 30% (on average). Once the optimal dose of levodopa is found, the side effects of this combination therapy are less than those of levodopa therapy (alone or with a decarboxylase inhibitor).

Side effects

In the face of monotherapy (sole treatment) with selegiline, the following effects or adverse reactions have been detected in isolated cases: dry mouth, nausea, insomnia and arrhythmias.increased liver enzyme values which are not clinically relevant.

If, on the other hand, we are dealing with a combined treatment of levodopa with selegiline, the following may appear: states of excitation, insomnia, feelings of tiredness, drowsiness, vertigo, headache, anxiety, restlessness, dizziness, anxiety, anxiety about the patient's condition.In rare cases, mental confusion, psychosis, urination disorders and dyspnea may occur, as well as dyskinesias, arterial hypotension, edema, lack of appetite, nausea, hallucinations, constipation and, in rare cases, states of mental confusion, psychosis, urination disorders and dyspnea.

All these adverse effects can be reduced in part by lowering the dose of levodopa, which is possible under combination therapy with selegiline.