Your answer was correct
-
A Dyskinesias occur in 80% of patients receiving L-dopa therapy for long periods Correct Answer
-
B It is a precursor to tyrosine
-
C Levodopa stops the progression of parkinsonism
-
D Carbidopa given with L-dopa worsens GIT side effects
Explanation
L-dpoa is an immediate precursor of dopamine. L-dopa is rapidly absorbed from the samll intestine, but its absorption depends on the rate of gastric emptying and the pH ofthe gastric contents. Food will delay the appearnace of L-dopa in the plasma. Adding carbidopa will reduce GIT side effects. (only 20%will suffer as opposed to 80% without carbidopa)1-3% enters the brain unaltered, but this number will be higher if given with dopa decarboxylase inhibitor. Concomitant administration of a peripheral dopa decarboxylase inhibitor (carbidopa) may reduce the daily requirement of levodopa by approximately 75%. L-dopa causes a positive Coombs test. L-dopa has a half life of between 1-3 hours but when administered with carbidopa, the plasma half lie is longer. Suddenly stopping L-dopa will cause tremor. This side effect part of the neuroleptic malignant syndrome which may occur on abrupt stopping of the drug. L-dopa does not stop the progression of parkinsonism but its early initiation will lower mortality.
Question 106
Which of the following cholinoceptor blocking drugs is the least absorbed by the brain?
Your answer was correct
-
A Ipratropium Correct Answer
-
B Scopolamine
-
C Atropine
-
D Benztropine
Explanation
Ipratropium is a quaternary amine-charged- and therefore poorly taken up by the brain and are relatively free-at low doses-of centrla nervous system effects. The other drugs are tertiary smines and are able to be takenup by the brain at lower doses.
Question 107
All of the following drugs prolong the refractory period in normal cells, except?
Your answer was not correct
-
A Amiodarone
-
B Lignocaine Correct Answer
-
C Quinine Your Answer
-
D Procainamide
Explanation
Lignocaine, Propanolol and Moricizine decrease the RP in normal cells. Adenosine, Diltiazem, Esmolol, Flecanide, Mexiletine,Tocainide and Verapamil have no effect on the RP of normal Cells
Question 108
Which local anaesthetic causes methaemaglobinaemia?
Your answer was correct
-
A Lignocaine
-
B Tetracaine
-
C Bupivacaine
-
D Prilocaine Correct Answer
Explanation
Question 109
Which drug-effect match is incorrect?
Your answer was correct
Explanation
Question 110
Regarding pancuronium, which statement is incorrect?
Your answer was correct
-
A It is a steroid
-
B It does not release histamine
-
C It is renally excreted
-
D It has a shorter duration of action than vecuronium Correct Answer
Explanation
Pancuronium’s duration of action >35min. Vecuronium’s duration of action is 20-35m
Question 111
Regarding atracurium, which of the following statements is correct?
Your answer was correct
-
A It has a longer duration of action than vecuronium
-
B It is not associated with histamine release
-
C It is a steroid derivative
-
D It is eliminated by non renal or liver dependant mechanisms Correct Answer
Explanation
Atracurium’s duration of action 20-35m which is the same as vecuronium. Atracurium releases histamine slightly. It is an isoquinolone derivative. And is eliminated by Hoffman (non renal/liver) elimination
Question 112
What is the correct order of catecholamine synthesis?
Your answer was not correct
-
A Tyrosine - dopamine - dopa - noradrenaline - adrenaline
-
B Tryptophan - dopa - dopamine - adrenaline - noradrenaline
-
C Tysosine - dopa- dopamine - adrenaline - noradrenaine Your Answer
-
D Tyrosine - dopa - dopamine - noradrenaline - adrenaline Correct Answer
Explanation
Question 113
Regarding St Johns Wort, which of the following statements is correct?
Your answer was correct
-
A It is more effective than placebo Correct Answer
-
B It has a side effect profile comparable to placebo
-
C Can cause hyperthermic or hypertensive reaction
-
D Has been trialed for the use in viral diseases
Explanation
St John’s wort is an enzyme inducer and has been trialed for depression. It has not trialed, and should therefore not be used for viral disease or cancers. Side effects: mania, photosensitization, autonomic arousal
Question 114
Which of the following is the major side effect of benztropine?
Your answer was correct
-
A Miosis
-
B Delirium Correct Answer
-
C Diarrohea
-
D Bronchorrhea
Explanation
The side effects are typical antimuscarinic side effects: mydriasis, delirium, flushing, lack of sweating (remember: blind as a bat, mad as a hatter, dry as a chip, red as a beet). The other options here represent cholinergic poisoning.
Question 115
A woman is hypertensive with potassium of 6.7. Which of the following drugs is LEAST likely to cause this?
Your answer was correct
-
A Spironalactone
-
B Frusemide Correct Answer
-
C ACE inhibitor
-
D Suxamethonium
Explanation
Frusemide decrease potassium levels.
Question 116
A young man is injected with an iv drug. He shows a resultant tachycardia, midriasis, normal blood pressure and reduced sweating. Which of the following drugs is most likely to have caused this?
Your answer was correct
-
A Nicotinic antagonist
-
B Muscarinic antagonist Correct Answer
-
C Cholinomimitic
-
D Adrenergic agonist
Explanation
Reduced sweating is a sign of anticholinergic poisoning. Others include mydriasis-blindness, delirium, flushing.
Remember “blind as a bat, mad as a hatter, red as a beet, dry as a chip”
Question 117
A patient arrives in the ED staggering, agitated, hyperthermic with dilated pupils. Which of the following drugs in overdose is least likely to produce these effects?
Your answer was not correct
-
A Atropine Your Answer
-
B Amphetamine
-
C Aspirin Correct Answer
-
D Tricyclic
Explanation
Aspirin OD does present with hyperthermia and agitation but does not cause mydriasis
Question 118
Which of the following is not a pharamcological characteristic of propranolol?
Your answer was not correct
-
A Lipid soluble
-
B Local anaesthetic action Your Answer
-
C Half life of 3-6 hours
-
D It has selective B receptor blocking properties Correct Answer
Explanation
Propanolol is a non-selective beta receptor blocker. It has no sympathomimetic activity. It is highly lipid soluble and readily crosses the BBB. Because of its Na channel blocking activity, it causes widening of the QRS and therefore VF arrest in overdose. It also causes seizures in overdose as it crosses the BBB. Treatment is bicarbonate. Half life 3.5-6hrs. Bioavailability <25%
Question 119
Of the following antipsychotics, which is most likely to cause extrapyramidal side effects?
Your answer was not correct
-
A Clozapine
-
B Chlorpromazine Your Answer
-
C Risperidone
-
D Haloperidol Correct Answer
Explanation
Chlorpromazine (a phenothiazine) causes medium EP side effects. Risperidone (atypical antipsychotic) cause high EP side effects. Haloperidol (a butyrophenone) causes very high side effects. Clozaoine (atypical antipsychotic) cause low EP side effects
Question 120
Of the following sedatives, which is the most potent?
Your answer was not correct
-
A Diazepam
-
B Midazolam Correct Answer
-
C Phenobarbitone Your Answer
-
D Chloral hydrate
Explanation
Potency is the dose required to produce 50% of THAT drugs effect. Phenobarbitone may have a stronger effect but it is required in much higher doses than midazolam and is therefore not as potent.
Question 121
Which of the following statements best describes buspirone's mechanism of action?
Your answer was correct
-
A Direct GABA stimulation
-
B Indirect GABA stimulation
-
C Direct noradrenaline receptor stimulation
-
D None of the above Correct Answer
Explanation
Buspirone relieves anxiety without sedation; it is a non-benzodiazapine anxiolytic. It is a partial agonist at 5HT1 and D2. There is no rebound anxiety on stopping drug. It takes a week to work, unsuitable in acute anxiety
Question 122
Regarding neurotransmitters in the brain, which of the following statements is correct?
Your answer was correct
-
A Strychnine stimulates glycine receptors
-
B Atropine antagonises GABA receptors
-
C Butyrophenones stimulate dopamine receptors
-
D Ondansetron antagonises serotonin receptors Correct Answer
Explanation
Strychnine antagonizes glycine receptors. Atropine is an antagonist at the M2 (muscarinic receptor). Butyrophenones antagonize the dopamine receptor
Question 123
Which of the following opiates is associated with seizures when given in high dose to patients with renal failure?
Your answer was correct
-
A Codeine
-
B Morphine
-
C Pethidine Correct Answer
-
D Methadone
-
E Fentanyl
Explanation
Question 124
Regarding SSRIs, which of the following statements is correct?
Your answer was not correct
-
A They may be associated with seretonin syndrome with muscle weakness, hyperpyrexia and confusion. Your Answer
-
B They are safe in overdose due to minimal drug interactions
-
C They are readily removed by dialysis.
-
D They may cause seizures in overdose Correct Answer
Explanation
SSRis are dangerous in OD because they can cause serotonin syndrome that consists of muscle rigidity, hyperpyrexia, and confusion, which can lead to convulsions, coma and rhabdomiolysis. Dialysis is of no benefit as they have high volumes of distrubution
Question 125
A patient on phenytoin is found to have a low blood phenytoin level. Of the following drugs, which is LEAST likely to cause this?
Your answer was not correct
-
A Carbemazepime Your Answer
-
B Non-compliance
-
C Disulfiram Correct Answer
-
D Hypoalbuminemia
Explanation
Disulfiram retards the metabolism of phenytoin. Carbamazapine is an enzyme inducer and will increase phenytoins metabolism. Non compliance obviously lowers blood levels. Because phenytoin is highly protein bound, low levels of albumin will decrease phenytoin blood levels
Question 126
Of the following drugs, which is the most dangerous in overdose?
Your answer was not correct
-
A Imipramine Correct Answer
-
B Moclobenide Your Answer
-
C Sertraline
-
D Paroxeteine
Explanation
Imipramine is a tricyclic antidepressant. In OD it causes VF arrest and coma. A dose of 10mg/kg of a TCA is lethal
Question 127
Which of the following drugs acts by MAO inhibition?
Your answer was not correct
-
A Clomipramine Your Answer
-
B Paroxetine
-
C Sertraline
-
D Moclobemide Correct Answer
Explanation
Clomipramine is a tricyclic antidepressent that prevents reuptake of noradrenaline (NA), serotonin.
Paroxetine is a selective serotonin reuptake inhibitor, antidepressant, no effect on NA
Sertraline is a selective serotonin reuptake inhibitor, antidepressant, no effect on NA
Note: Paroxetine and sertraline have no antimuscarinic action (unlike chlomipramine)
Question 128
Carbamazepine is closely related to which of the following drugs?
Your answer was not correct
-
A Quinidine Your Answer
-
B Sodium valproate
-
C Metoprolol
-
D Imipramine Correct Answer
Explanation
Carbamazapine resembles (in it's chemical structure only) tricyclic antidepressants, of which Imipramine is one
Question 129
Which of the following drugs is a direct serotonin agonist?
Your answer was correct
-
A Fluoxeteine
-
B Amitryptiline
-
C Moclobemide
-
D Sumatriptan Correct Answer
Explanation
Fluoxetein = Selective Serotonine reuptake inhibitor SSRI
Amitryptiline = Tricyclic antidepressant : Blocks reuptake of noradrenaline and serotonin.
Moclobemide = Competitively and reversibly inhibits monoamine oxidase MAO A (selective). Note: from the evidence available, the reversible short acting MAO inhibitor moclobemide, appears to be relatively free of the hypertensive reaction due to tyramine.
Sumatriptan is a selective agonist for 5-HT1D and 5-HT 1B receptors.
Question 130
Regarding neuromuscular junction blockers, which of the following statements is correct?
Your answer was not correct
-
A Pancuronium causes histamine release Your Answer
-
B Vecuronium is an isoquinolone derivative
-
C Gallium is eliminated by the liver
-
D Gentamicin increases their efficacy Correct Answer
Explanation
Pancuronium does not cause histamine release. Vecuronium is a steroid derivative. The kidney eliminates Gallamine only.
Question 132
Which of the following drugs is not an amide local anaesthetics?
Your answer was correct
-
A Prilocaine
-
B Lignocaine
-
C Bupivicaine
-
D Benzocaine Correct Answer
Explanation
Other amide local anaesthetics include mepivacaine, etidocaine, ropivocaine
Question 133
At low dose, which of the following muscle relaxants is most commonly associated with tachycardia?
Your answer was not correct
-
A Suxamethonium
-
B Atracurium
-
C Vecuronium Your Answer
-
D Gallamine Correct Answer
Explanation
Pancuronium can also cause a tachycardia but to a lesser degree
Question 134
All the following drugs are anaesthetic agents except?
Your answer was not correct
-
A Midazolam Your Answer
-
B Glycopyrolate Correct Answer
-
C Propofol
-
D Etomidate
Explanation
Question 135
Which of the following drugs has the greatest MAC?
Your answer was correct
-
A Nitrous oxide Correct Answer
-
B Halothane
-
C isoflurane
-
D Methoxyflurane
Explanation
NO-100%
halothane-0.75%
isoflurane 1.4%
methoxyflurane-0.16%
Question 136
Which of the following muscle relaxants has the longest duration of action?
Your answer was correct
-
A Atracurium
-
B Pancuronium Correct Answer
-
C Vecuronium
-
D Rocuronium
Explanation
Atracurium-20-35m
mivacurium-10-20m
vecuronium-20-35m
rocuronium 20-35m
Question 137
A patient complains of muscle pain post-operatively. Which of the following drugs is most likely to cause this?
Your answer was not correct
-
A Propofol
-
B Suxamethonium Correct Answer
-
C Atracurium Your Answer
-
D Ketamine
Explanation
Muscle pain due to the depolarizing action of suxamethonium
Question 138
What is the most common adverse effect of procainamide?
Your answer was not correct
-
A Anaphylaxis
-
B Bradycardia Your Answer
-
C Fever
-
D Hypotension Correct Answer
Explanation
Hypotension especially when administered IVI as it has ganglion-blocking properties
Question 139
Which of the following statements regarding L-Dopa is correct?
Your answer was correct
-
A L-dopa can be taken with food
-
B Drug holidays are recommended to improve the the responsiveness to levodopa
-
C Suddenly stopping it will cause tremor Correct Answer
-
D L-dopa's half life is unaffected when given with carbidopa
Explanation
L-dopa is an immediate precursor of dopamine. L-dopa is rapidly absorbed from the samll intestine, but its absorption depends on the rate of gastric emptying and the pH ofthe gastric contents. Food will delay the appearnace of L-dopa in the plasma. 1-3% enters the brain unaltered, but this number will be higher if given with dopa decarboxylase inhibitor. Concomitant administration of a peripheral dopa decarboxylase inhibitor (carbidopa) may reduce the daily requirement of levodopa by approximately 75%. L-dopa causes a positive Coombs test. L-dopa has a half life of between 1-3 hours but when administered with carbidopa, the plasma half life is longer. Suddenly stopping L-dopa will cause tremor. This side effect part of the neuroleptic malignant syndrome which may occur on abrupt stopping of the drug. Because a drug holiday may only temporarily improve responsiveness to levodopa and due to the risks of aspiration, PE, venous thromboembolism and depression (from the increasing immobility) during a drug holiday, they are not recommended.
Question 140
Regarding sodium valproate, which of the following statements is correct?
Your answer was not correct
-
A T1/2 is 40 hrs
-
B It's VD is 0.6L/kg Your Answer
-
C It is lipid soluble Correct Answer
-
D It has a high first pass metabolism
Explanation
Sodium valporate has a VD of 0.15L/kg. Its bioavailability is 80% so it has a low first pass metabolism rate. Half life varies from 9-18hrs. Peak blood levels are observed within 2 hrs. pKa of 4.7. 90% bound to plasma proteins.
Question 141
A young male presents with a high blood pressure, mydriasis and a high temperature. Which drug has he most likely taken?
Your answer was not correct
-
A Atropine Your Answer
-
B Adrenaline
-
C Naloxone
-
D Cocaine Correct Answer
Explanation
Cocaine is a sympathomimetic stimulant which cause cardiovascular, CNS and peripheral sympathetic stimulation
Question 142
Which of the following statements regarding neuromuscular junction blockers is incorrect?
Your answer was not correct
-
A Vecuronium is predominantly renally excreted Correct Answer
-
B Atracurium is inactivated by Hofmann elimination
-
C Pancuronium has a longer duration of action than vecuronium Your Answer
-
D Pancuronium and vecuronium are both steroid neuromuscular blocking drugs
Explanation
Vecuronium is excreted by the liver- 85% and renal- 15%.
Pancuromium’s duration of action is >35m and vecuronium’s 20-35min.
Vecuronium, pancuronium, pipecuronium and rocuronium are steroid neuromuscular blocking drugs.
Tubocurarine, atracurium and doxacurium are isoquinoline neuromuscular blocing drugs.
Question 143
Regarding drugs that are used to treat glaucoma, which is the correct pairing of drug-mechanism of action?
Your answer was correct
-
A Pilocarpine - ciliary muscle contraction Correct Answer
-
B Timolol - ciliary muscle contraction
-
C Acetazolamide - increased aqueous production
-
D Latanoprost - increased aqueous production.
Explanation
Timolol-decreases aqueous secretion.
Acetazolamide-decreases aqueous secretion due to a lack of HCO3.
Latanoprost-increased outflow of aqueous.
PG-increased outflow.
Beta blockers-decreased aqueous secretion
Question 144
Regarding ergotamine, which of the following statements is incorrect?
Your answer was correct
-
A It works well in the early treatment of acute migraine
-
B It can be given parenterally
-
C It causes vasoconstriction
-
D It causes GI haemmorhage. Correct Answer
Explanation
Question 145
Regarding L-dopa, which of the following statements is correct?
Your answer was correct
-
A It has a half life of 5 hours
-
Share with your friends: |