RCOA Guide to the FRCA Examination The Primary (fourth edition) - Pharmacology Flashcards
Cisatracurium:
is one of two stereoisomers in atracurium
False. Cisatracurium is one of the ten stereoisomers present in atracurium.
Cisatracurium:
is of equal potency to atracurium
False. It is three to four times more potent than atracurium.
Cisatracurium:
undergoes direct hydrolysis by plasma-esterases
False. It does not undergo direct hydrolysis by plasma esterases, but is predominantly eliminated by Hofmann elimination to laudanosine and a monoquaternary acrylate.
This is then hydrolysed by non-specific plasma esterases to a monoquaternary alcohol and acrylic acid.
Cisatracurium:
has no active metabolites
True. None of the metabolites of cisatracurium have neuromuscular blocking properties
Cisatracurium:
is more dependent than atracurium on renal function for excretion
False. The elimination of both atracurium or cisatracurium is independent of renal function.
Propofol:
Is a water soluble phenol compound
False. Propofol is insoluble in water but highly soluble in fat and requires preparation as a lipid emulsion.
Propofol:
Has an elimination half-life of less than one hour
False. It has a terminal elimination half-life of five to twelve hours.
Propofol:
Glucuronidation occurs through the hydroxyl group at position 1
True.
Propofol:
Acts only on the ß subunit of the GABA receptor
False. As well as acting on the B subunit of the GABA receptor it also enhances the effect of glycine which is the major inhibitory. transmitter in the brainstem and spinal cord. It also inhibits neurotransmission at excitatory central nicotinic acetylcholine receptors.
Propofol:
Has anti-emetic effects which may be due to dopamine
antagonism
True. Antagonism of the D2 receptor is a possible mechanism for its anti-emetic
The following are true of local anaesthetic drugs:
Lidocaine and tetracaine (amethocaine) are both amides
False. Tetracaine (amethocaine) is an ester local anaesthetic.
The following are true of local anaesthetic drugs:
Potency is related to lipid solubility
True. Potency is closely related to lipid solubility in vitro.
The following are true of local anaesthetic drugs:
Rate of onset of action is independent of dose administered
False. Rate of onset of action is closely related to pKa.
Increasing the dose will increase the absolute amount of unionised drug present and hence increase the speed of onset.
The following are true of local anaesthetic drugs:
Ester local anaesthetic drugs are all poorly bound to plasma proteins
False. Cocaine is 95% plasma protein bound.
The following are true of local anaesthetic drugs:
Ropivacaine is more potent than lidocaine
True. Ropivacaine is four times more potent than lidocaine, reflecting its greater lipid solubility.
Phase I depolarisation blockade:
Shows ‘fade’ during tetanic stimulation
False. Fade is a feature of partial non-depolarising blockade.
Pre-junctional nicotinic receptors normally provide positive feedback to maintain transmitter release during periods of high neuromuscular activity; fade may be caused by non-depolarising neuromuscular blocking drugs acting at pre-junctional receptors. No fade is seen during tetanic stimulation in the presence of partial depolarisation blockade.
Phase I depolarisation blockade:
May be potentiated by anticholinesterases
True
Phase I depolarisation blockade:
Shows post-tetanic facilitation
False. Post-tetanic facilitation is a feature of non-depolarising blockade.
Phase I depolarisation blockade:
Is prolonged by prior administration of a small dose of a non-depolarising relaxant
False. Small doses of non-depolarising neuromuscular blockers were previously given in an attempt to decrease muscle pains after succinylcholine but have no effect on phase 1 block itself. Phase 1 block may be potentiated by volatile agents, anticholinesterases, magnesium and lithium.
Phase I depolarisation blockade:
Is antagonised by dantrolene
False. Dantrolene prevents release of calcium from the sarcoplasmic reticulum and may cause skeletal muscle weakness.
Adverse effects of heparin include:
Thrombocytopenia
True. Immune mediated heparin-induced thrombocytopaenia is serious and often associated with thrombotic complications. A non-immune thrombocytopaenia also occurs but is rarely of clinical significance.
Adverse effects of heparin include:
Hyperkalaemia
True. This is caused by inhibition of aldosterone secretion.
Adverse effects of heparin include:
Hypersensitivity reactions
True
Adverse effects of heparin include:
Intra-uterine fetal haemorrhage
False. Heparin has low lipid solubility and does not cross the placenta.