Antidepressants - TCAs Flashcards
What are examples of tricyclic antidepressants?
- Amitryptilline
- Nortryptilline
- Imipramine
What are indications for TCAs?
- 2nd Line treatment for moderate - severe depression
- Neuropathic pain
How do TCAs work?
Inhibit neuronal reuptake of serotonin (5-HT) and noradrenaline from the synaptic cleft, thereby increasing their availability for neurotransmission. They also block a wide array of receptors, including muscarininc, histamine, a-adrenergic and dopamine receptors
Why do TCAs have an extensive side effect profile?
Due to their effect on mutliple receptors, including histamine, dopamine, muscarinic and a-adrenergic receptors
What are common adverse side effects of TCAs?
- Antimuscarinic effects - Dry mouth, constipation, urinary retention, blurred vision
- Sedation
- Hypotension
- Prolonged QTc
- Arrythmias
- Convulsions
- Hallucinations
- Mania
- Breast changes
- Sexual dysfunction
- Extrapyramidal symptoms
What are features of TCA overdose?
- Hypotension
- Arrhythmias
- Convulsions
- Coma
- Respiratory failure
What effects can sudden withdrawal of TCAs cause?
- Gastrointestinal upset
- Neurological
- Influenza-like symptoms
- Sleep disturbance
When should TCAs be used with caution?
- Elderly
- CV disease
- Epilepsy
- Constipation
- Prostatic hypertrophy
- Raised intraocular pressure
What drug should TCAs not be given with?
MAOi - can precipitate hypertension, hyperthermia or serotonin syndrome
How soon after starting someone on amitryptilline should symptoms of depression be reviewed?
1-2 weeks - if no response after 4 weeks, consider changing
How long would you treat someone with TCAs for first episode of depression?
6 months
How long should you treat someone with TCAs who is suffering from recurrent depression?
2 years
What advise would you give a patient when starting them on TCAs?
- Warn them not to stop treatment suddenly as this may cause flu-like withdrawal symptoms and sleeplessness
- Warn of any side effects
