Question
A 29-year employee gradually stopped going out, withdrew socially. He felt guilty, worthless and tired all time, lost interest in pleasure and sex and had disturbed sleep. Physician diagnosed him a case of Major depression. (
- (a) Enumerate three drug groups with two examples each to treat major depression. ( 5 mark(s)
- (b) Write the mechanism of action, uses and adverse effects of Fluoxetine. ( 5 mark(s)
- (c) Briefly describe Atypical Antipsychotics 5 mark(s)
Answer
a) Three drug groups for major depression, two examples each
| Class | Examples |
|---|---|
| SSRIs | Fluoxetine, Sertraline |
| SNRIs | Venlafaxine, Duloxetine |
| Tricyclic antidepressants (TCAs) | Amitriptyline, Imipramine |
b) Fluoxetine — mechanism, uses, adverse effects Mechanism: selectively inhibits presynaptic serotonin (5-HT) reuptake transporter, raising synaptic serotonin availability; downstream adaptive receptor changes over several weeks produce the antidepressant effect. Uses: major depressive disorder (first-line), obsessive-compulsive disorder, panic disorder, bulimia nervosa. Adverse effects: nausea/GI disturbance, sexual dysfunction, insomnia/agitation (fluoxetine is more activating than other SSRIs), serotonin syndrome risk with other serotonergic drugs/MAOIs, initial transient increase in suicidal ideation particularly in adolescents — directly relevant to this patient’s presentation and requiring close monitoring at treatment initiation.
c) Atypical antipsychotics Combine dopamine D2 receptor antagonism with serotonin (5-HT2A) receptor antagonism, unlike typical antipsychotics’ pure D2 blockade. Examples: Olanzapine, Risperidone, Quetiapine, Clozapine. Advantages: substantially lower risk of extrapyramidal symptoms/tardive dyskinesia, greater efficacy against negative symptoms of schizophrenia. Trade-off: greater metabolic adverse effects (weight gain, dyslipidemia, new-onset diabetes), most pronounced with olanzapine/clozapine; clozapine additionally requires mandatory blood count monitoring for agranulocytosis risk, reserved for treatment-resistant disease.