What is the vasoconstrictive mechanism of action of methylene blue?
Inhibits nitric oxide induced cGMP activity resulting in vasoconstriction.
How does vancomycin work?
Glycopeptide antibiotic: Inhibit cell wall synthesis by binding to and interfering with the ongoing synthesis of peptidoglycan cell wall.
What is carboprost?
Prostaglandin F2-alpha analogue used in management of PPH. It can precipitate bronchospasm.
What is the mechanism of action of nicorandil?
Potassium channel activator
Activation of ATP-sensitive potassium channels within the walls of arterioles causes hyperpolarisation, which reduces intracellular calcium. In turn, this leads to arteriolar vasodilation and subsequent reduced blood pressure.
Describe the pKa, protein binding and relative solubility of prilocaine.
Which class of antibiotics exhibits concentration-dependent killing?
Aminoglycosides
(the higher the concentration, the greater the bactericidal action)
Beta-lactams are time-dependent.
What is the mechanism of action of aminoglycoside antibiotics?
Prevent protein synthesis by binding to the 30S ribosomal subunit
Which classes of antibiotics work by inhibiting bacterial protein synthesis?
50S: macrolides, clindamycin, chloramphenicol
30S: aminoglycosides, tetracycline
Which intravenous antiviral agent causes obstructive crystal nephropathy?
Aciclovir
What is a structural isomer of dobutamine used in anaesthetics?
Dihydrocodeine
What dose of intralipid should be used in local anaesthetic toxicity?
1: Bolus Dose at 1.5 ml/kg over 1 min
2: Infusion at 15 mL/kg/hour
3: Second Bolus + Increase Infusion to 30 mL/kg/hour (if cardiovascular instability not sorted)
List the absolute contraindications for parecoxib.
Which antacids are absorbed in the GI tract and which are not absorbed?
NOT Absorbed: magnesium and aluminium
Absorbed: sodium bicarbonate and sodium citrate
Aluminium causes constipation whereas magnesium causes diarrhoea.
What is the maximum safe dose of bupivacaine?
2 mg/kg
Adrenaline does NOT change max safe dose (as bupivacaine is already vasoconstricting).
What is the maximum cumulative dose of intralipid that can be given?
12 ml/kg over 30-60 mins
I.e. 840 ml for a 70kg adult.
Outline the Vaughan-Williams classification of antiarrhythmics.
What is the mechanism of action of trimetaphan?
Centrally acting ganglion blocker that reduces blood pressure by competing with nicotinic acetylcholine receptors in parasympathetic and sympathetic ganglia.
List antiarrhythmics based on their effectiveness for supraventricular, ventricular, or both types of tachyarrhythmia.
Which pharmacokinetic features affect a local anaesthetic’s potency, speed of onset, and duration of action?
State the protein-binding, volume of distribution and half-life of amiodarone.
Describe the activity of dopamine at different dose ranges.
Which local anaesthetic can cause methaemoglobinaemia?
Prilocaine
Which uterotonic agent is contraindicated in pre-eclampsia and why?
Ergometrine can cause coronary vasospasm and hypertension and therefore is contraindicated in pre-eclampsia.
Which alpha blocker is an irreversible alpha antagonist and, hence, has a long duration of action?
Phenoxybenzamine
Non-selective irreversible alpha antagonist (new receptors must be synthesised to overcome the effect).