Tricyclic Antidepressants - Amitryptiline Flashcards
What is amitriptyline used for?
1) 2nd line for moderate to severe depression (when SSRIs are ineffective)
2) neuropathic pain
How do tricyclic antidepressants like amitriptyline work?
- inhibit neuronal reuptake of serotonin and noradrenaline
- so increase their availability for neurotransmission.
- improves mood / physical symptoms
- Tricyclic antidepressants block a wide array of receptors e.g. muscarinic, histamine (H1), alpha-adrenergic, dopamine D2 receptors.
Tricyclic antidepressants work by inhibiting neuronal reuptake of serotnin and noradrenaline.
They also block a wide array of receptors - which ones?
- muscarinic
- histamine (H1)
- alpha adrenergic (a1/a2)
- dopamine (D2)
What are the side effects of tricyclic antidepressants such as amitriptyline?
blockade of antimuscarinic receptors:
- dry mouth (due to
- constipation
- urinary retention
- blurred vision
blockade of H1 and a1 receptors:
- sedation
- hypotension
- ECG changes (prolonged QT/QRS)
- arrhythmias
- convulsions
- hallucinations
- mania
blockade of D2:
- breast changes
- sexual dysfunction
- tremor
- dyskinesia
resp failure, hypotension, convuslions, coma, arrhythmias in overdose - fatal
what are the side effects of sudden withdrawal of tricyclic antidepressants like amitriptyline?
- GI upset
- neuro symptoms
- flu like symptoms
- sleep disturbance
What are the side effects caused by amitriptyline due to blockade of antimscarinic receptors ?
- dry mouth
- urinary retention
- blurred vision
What are the side effects causes by blockade of H1 and a1 receptors by amitriptyline?
- sedation
- hypotension
- cardiac effects (QT/QRS prolonged —-> arrhythmias)
What are the side effects caused by blockade of dopamine receptors by amitriptyline>
- breast changes
- sexual dysfunction
- tremor
- dyskinesis
What are the contraindications of tricyclic antidepressants?
- elderly
- cardiovascular disease
- epilepsy
- constipation
- prostatic hypertrophy
- raised intraocular pressure
what are the drug interactions of tricyclic antidepressants?
DO NOT give with :
- monoamine oxidase inhibitors ( both increases serotonin and noradrenaline —-> hypertension/hyperthermia/serotonin syndrome)
Why should tricyclic antidepressants like amitriptyline not be given with monoamine oxidase inhibitors?
- both classes of drugs increases serotonin and noradrenaline at synapses —> hypertension and hyperthermia or serotonin syndrome
What is serotonin syndrome?
- high body temp
- agitation
- tremor
- dilated puplils
What is the dose of amitriptyline for depression vs neuropathic pain?
- depression = 75mg daily
- neuropathic pain = starting dose 10mg at night
