Anti-depressants
Major depression and mania are two extremes of affective disorders which refer to a pathological change in a mood state.
- Major Depression is characterized by symptoms like sad mood, loss of interest and pleasure, low energy, worthlessness, guilt, psychomotor retardation or agitation, change in appetite or sleep, melancholia, suicidal thoughts etc.
- mania refers to elation or irritable mood, racing thoughts, accelerated speech, increased activity, reduced sleep, reckless or violent behaviour and may be progressive loss of contact with reality.
- In bipolar disorders, cyclical swings mood from mania to depression are seen. The mood change may have a psychotic basis with delusional thinking or occur in isolation and induce anxiety.
Drugs used in these conditions are grouped into:
- Antidepressants.
- Antimanics (Mood stabilizer)
Antidepressants
These are drugs which can elevate mood in depressive illness. Practically all anti-depressants affect monoaminergic transmission in the brain in one way or other.
Classification:
- Reversible inhibitors of MAO-A (RIMAs)
Moclobemide, Clorgyline. - Tricyclic Anti-depressants (TCAs)
- NA + 5-HT reuptake inhibitors. e.g Imipramine, Amitriptyline, Trimipramine, Doxepin, Dothiepin, Clomipramine.
- Predominantly NA reuptake inhibitors. e.g.Desipramine, Nortriptyline, Amoxapine.
- Selective serotonin reuptake inhibitors (SSRIs) E.g. Fluoxetine, Fluvoxamine, Paroxetine, Sertaline, Citopram.
- Atypical antidepressants eg Trazadone, Mianiserin, Mirtazapine, Venlafaxine , Tianeptine, Amineptine, Bupropion.
Pharmacological Actions:
The TCAs inhibit monoamine uptake and interact with a variety of receptors viz. muscarinic, α adrenergic, histamine H1, 5-HT1, 5-HT2 and occasionally dopamine D2. However, relative potencies at these sites differ among different compounds. The newer selective serotonin re-uptake inhibitors (SSRIs) and atypical anti-depressants interact with fewer receptors and have more limited spectrum of action (produce fewer side effects).