TCAs & Tricyclic-related antidepressants

Question 1

MoA

Answer 1

Inhibits the reuptake of 5-HT + NA
Also blocks a wide array of receptors (M, H1, alpha1/2 and D2)

Question 2

Sedating TCAs

Answer 2

Give in anxious, agitated patients

Amitriptyline (also used in neuropathic pain)
Clomipramine
Dosulepin (dangerous in overdose - specialist use)
Doxepin
Trimipramine

Question 3

Less sedating TCAs

Answer 3

Given in withdrawn, apathetic patients

Imipramine (most antimuscarinic effects)
Lofepramine (rarely causes hepatotoxicity)
Nortriptyline (also used in neuropathic pain)

Question 4

Tetracyclic antidepressants

Answer 4

Sedating
Given in anxious, agitated patients

Mianserin
Trazodone

Question 5

Side effects

Answer 5

More sedating, epileptogenic (seizures), cardiotoxic and antimuscarinic than SSRIs.
They are also more toxic in overdose.

Question 6

Cardiac side effects

Answer 6

QT prolongation
Arrhythmias
Heart block
Hypertension

Question 7

Antimuscarinic side effects

Answer 7

Dry mouth
Blurred vision
Constipation
Tachycardia
Urinary retention
Pupil dilation
Raised intraocular pressure
Angle closure glaucoma

Question 8

Other side effects

Answer 8

Hallucinations
Mania (increased 5-HT/NA)
Hypotension (alpha blockade)
Sexual dysfunction
Breast changes
Extrapyramidal SE (d blockade)

Question 9

Interactions - increased plasma concentrations

Answer 9

Cimetidine (enzyme inhibitors)

Question 10

Interactions - increased risk of hyponatraemia

Answer 10

Diuretics (loop/thiazide)
Desmopressin
Carbamazepine

Question 11

Interactions - increased risk of QT prolongation (clomipramine)

Answer 11

Amiodarone
Sotalol
Antipsychotics
Citalopram/escitalopram
Loop/thiazide diuretics
B2 agonists
Corticosteroids
Theophylline

Question 12

Interactions - increased risk of hypotension

Answer 12

Antihypertensive
- Alpha blockers
- Beta blockers
- ACEi
- CCBs
Antipsychotics
Levodopa/dopaminergic
NSAIDs
SGLT2 inhibitors (gliflozin)
Diuretics
Phosphodiesterase type-5 inhibitors (sildenafil)

Question 13

Interactions - increased risk of hypotension

Answer 13

Antimuscarinic drugs
Antihistamines
Atropine
Antipsychotics

Question 14

Interactions - increased risk of serotonin syndrome

Answer 14

MAOIs/selegiline (MAO-B inhibitor)
Tramadol
Amphetamines, 5-HT1a agonists e.g. sumatriptan, SSRIs
5-HT3 receptor antagonists e.g. ondansetron
Lithium