Antidepressants

Question 1

TCA common indications

Answer 1

2nd line for moderate-severe depression where SSRI were ineffective

treatment for neuropathic pain (liceened)

Question 2

TCA MOA

Answer 2

inhibit the neuronal uptake of 5HT and noradrenaine from the synpatic clef- increasing the availabiltiy for transmission. TCA block array of receptors including muscarinic, histamine, alpha adrenaline and dopamine.

Question 3

Adverse effects of TCA

Answer 3

antimuscarinic: dry mouth, constipation, urinary retention, blurred vision

blockage of H1 and alpha 1 receptors: sedation, hypotension

cardiac: arrhythmias, ECG changes (prolonged QT and QRS)
brain: convulsion, hallucinatoins, mania

dopamine blockage: sexual dysfunction, breast changes, extrapyramidal side effects (rare)

Question 4

TCA OD

Answer 4

hypotension, arrhythmias, convulsion, coma, respiratory failure
sudden withdrawl can cause GI upset, neuro and influenza like symptoms and sleep disturbance

tx sodium bicarbonate

Question 5

TCA contraindication

Answer 5

elderly, epilepsy, CVS disease, prostatic hypoertrophy, glaucoma, constipation
people with tachycarrhythmias

do not give with monoamine oxidase inhibitor as both increase 5HT and noradrenaline levels at the synpase which can precipitate hypertension and hyperthermia or SSRI

Question 6

TCA perscribing

Answer 6

depression- trial another SSRI before TCA. (75mg)
neuropathic pain- amitryptline in lower doses (10mg at night)
tablet/oral solutoin