• WHAT IS ANTIDEPRESSANT DRUGS
These drugs by modifying elevate mood in mental depression. Most of the drugs act by modifying monoaminergic transmission...
• WHAT IS THE CLASSIFICATION OF THE ANTIDEPRESSANT DRUGS ---
These are mainly four types with their sub-parts.
1. Reversible inhibitors of MAO-A (RIMAs)
a) MOCLOBEMIDE
b) Clorgyline
2. Tricyclic antidepressants (TCAs)
a) Imipramine
b) Amitriptyline
c) Clomipramine
d) Desipramine
e) Nortriptyline
3. Selective serotonin reuptake inhibitor (SSRIs)
a) Fluoxetine
b) Sertraline
c) Citalopram
d) Escitalopram
4. Atypical antidepressants
a) Trazodone
b) Minaserin
c) Duloxetine
d) Bupropion
• WHAT IS MOCLOBEMIDE:
It is a reversible, selective, short-duration MAO-A inhibitor. MAO activity is restored within two days of stopping the drug. It is an effective antidepressant. It does not produce sedative, anticholinergic and cardiovascular adverse effects. It is a preferred drug in elderly patients and those with heart disease.
•WHAT IS TRICYCLIC ANTIDEPRESSANTS(TCAs):
Drugs that belong to this group are imipramine, Amitriptyline, Clomipramine, Desipramine, and Nortryptyline.
•WHAT IS THE MECHANISM OF ACTION OF ANTIDEPRESSANT DRUGS:
TCAs act by inhibiting the reuptake of biogenic amines ( Noradrenaline (NA) and 5- Hydroxytryptamine (5- HT). This leads to increased concentration of these amines in the CNS. This contributes to antidepressant action.
•WHAT IS THE PHARMACOLOGICAL ACTION OF TRICYCLIC ANTIDEPRESSANT DRUGS:-
1. CNS: In normal individuals, TCAs produce tiredness, sleepiness, difficulty in concentration and thinking. In depressed patients, they have an elevation of mood ( in 2 to 3 weeks). Also, the patient becomes interested in self and surroundings. They do not produce euphoria but correct depression ., Seizure threshold is lowered, and they may produce convulsions.
2. ANS: They produce anticholinergic effects like dry mouth, blurred vision, constipation, and urinary hesitancy.
3. CVS: Postural hypotension and cardiac arrhythmias.
• WHAT IS THE ABSORPTION AND SECRETION OF TRICYCLIC ANTIDEPRESSANT DRUGS:
Oral absorption is excellent but slow. They are highly bound to plasma proteins. Extensively metabolized in the liver. Metabolites are eliminated in urine for 1 to 2 weeks.
•ADVERSE EFFECT OF TRICYCLIC ANTIDEPRESSANTS(TCAs):
1. Anticholinergic effects like dry mouth, constipation, and urinary retention.
2. Sedation and mental confusion.
3. Lowered seizure threshold and convulsions
4. Prostural hypotension
5. Cardiac arrhythmias.
• WHAT IS SELECTIVE SEROTONIN REUPTAKE INHIBITOR (SSRIs):
These are now first-line drugs in the treatment of depression. Drugs that belong to this group are Fluoxetine, Fluvoxamine, Sertraline, Citalopram, and Escitalopram. They do not have anticholinergic, cardiovascular, or neurological side effects as produced by TCAs. Also, they do not produce sedation or postural hypotension. They do not precipitate seizures. They are relatively safe and better acceptable.
• WHAT IS ADVERSE EFFECT OF SELECTIVE SEROTONIN REUPTAKE INHIBITOR ( SSRIs):-
1. Gastrointestinal such as nausea due to 5HT3 receptor stimulation
2. Weight gain
3. Interference with ejaculation and orgasm.
4. Nervousness, restlessness, insomnia, and anorexia
5. Epistraxis and ecchymosis due to platelet dysfunction.
• WHAT IS ATYPICAL ANTIDEPRESSANTS:
Atypical antidepressants include Trazadone, Minaserin, Duloxetine, and Bupropion.
• WHAT IS THE ADVANTAGE OF ATYPICAL ANTIDEPRESSANTS:-
1. Less sedation and fewer anticholinergic effects.
2. Safer in overdose.
3. Effective in patients not responding to TCA.
•WHAT IS TRAZADONE: It has prominent 02 blocking and weak 5-HT, aggressive action. It is short-acting (t 1/2 - 6 hrs.). It can produce a prolonged and painful penile erection ( priapism).
• WHAT IS MINASERIN: It blocks presynaptic O2 receptors. So increases the release and turnover of noradrenaline in the brain. This is responsible for the antidepressant effect.
You must be logged in to post a comment.