Tricyclic Antidepressants - Amitryptiline Flashcards
(13 cards)
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
