Clinical Therapeutics & BNF Guidelines Flashcards

What is the mechanism of action of selective serotonin reuptake inhibitors (SSRIs)?

Answer: Block serotonin reuptake at the presynaptic terminal

SSRIs inhibit the serotonin transporter (SERT), preventing reuptake of serotonin into the presynaptic neuron, increasing serotonin availability in the synapse.

According to NICE, which antidepressant class should be avoided in patients with a recent MI?

Answer: Tricyclic antidepressants (TCAs)

TCAs have cardiotoxic effects including QT prolongation and arrhythmia risk, making them contraindicated post-MI. SSRIs are preferred for depression post-MI.

Which proton pump inhibitor has the most significant interaction with clopidogrel?

Answer: Omeprazole

Omeprazole and esomeprazole are potent CYP2C19 inhibitors, reducing conversion of clopidogrel to its active metabolite. Pantoprazole has the least effect.

What is serotonin syndrome and which combination most commonly causes it?

Answer: Dangerous serotonergic excess; SSRI + tramadol

Serotonin syndrome is life-threatening excess serotonin activity causing hyperthermia, clonus, and agitation. SSRI combined with tramadol (also serotonergic) is a common precipitant.

A patient is prescribed lithium. Which monitoring parameter is most critical?

Answer: Serum lithium levels, renal function, and thyroid function

Lithium has a narrow therapeutic index. Regular monitoring of serum lithium (0.4–1.0 mmol/L), renal function (lithium is renally cleared), and thyroid function is essential.

According to BNF, what is the first-line treatment for Helicobacter pylori eradication?

Answer: Triple therapy: PPI + amoxicillin + clarithromycin for 7 days

UK first-line H. pylori eradication is triple therapy: a PPI + amoxicillin + clarithromycin for 7 days. Clarithromycin resistance affects choice in some areas.