New Discussion-- Pharmacotherapy of Depression

[Guest guest]

Respected members,

The second class of drugs are the tricyclic antidepressants.

TRICYCLIC ANTI-DEPRESSANTS

MECHANISM OF ACTION

Block uptake of SER and NE from the postsynaptic terminal – responsible for major action

Inhibition of transporters ----- NET and SERT

OTHER ACTIONS

Facilitation of SER (and DA) through á1 hetero-ceptors

Secondary down-regulation of 5HT1 auto-receptors and 5HT2 postsynaptic receptors

Secondary down-regulation of D2 auto-receptors and postsynaptic auto-receptors

Narrow therapeutic range leading to increased incidence of toxicity (35%)

100-250 ng/ml – Therapeutic

500 ng/ml and above – toxic

"Poor correlation between serum concentration and clinical effect"

ADR: central anticholinergic and antihistaminic effects, postural hypotension (á1 blocking), sedation, weight gain

Contraindicated in cardiac patients

- Cardiac depressant action (act on fast Na+ channels)

- Tachycardia – anti-cholinergic and adrenergic action

Dr Ankush Gaikwad

Second year resident, Department of Pharmacology

GMC, Nagpur.