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Question 1
Correct
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All of the following are indications for beta-blockers EXCEPT for:
Your Answer: Prinzmetal's angina
Explanation:Beta-blockers are contraindicated in Prinzmetal’s angina.Beta-blockers may be indicated in:HypertensionPheochromocytoma (only with an alpha-blocker)AnginaSecondary prevention after ACSArrhythmias including atrial fibrillationHeart failureThyrotoxicosisAnxietyProphylaxis of migraineEssential tremorGlaucoma
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 2
Incorrect
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Regarding aspirin at analgesic doses, which of the following statements is CORRECT:
Your Answer: As an analgesic, it has duration of action about 12 hours.
Correct Answer: It is contraindicated in patients with severe heart failure.
Explanation:Aspirin (at analgesic doses) is contraindicated in severe heart failure. Aspirin irreversibly inhibits cyclooxygenase (COX) enzymes resulting in decreased production of prostaglandins (which can lead to irritation of the gastric mucosa). The analgesic dose is greater than the antiplatelet dose, and taken orally it has a duration of action of about 4 hours. Clinical features of salicylate toxicity in overdose include hyperventilation, tinnitus, deafness, vasodilatation, and sweating.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 3
Incorrect
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Which of the following statements about lithium treatment is FALSE:
Your Answer: Lithium toxicity occurs at serum lithium concentrations of approximately 1.5 mmol/L and above.
Correct Answer: Concomitant treatment with NSAIDs decreases serum-lithium concentration.
Explanation:Lithium levels are raised by NSAIDs because renal clearance is reduced. Lithium is a small ion (74 Daltons) with no protein or tissue binding and is therefore amenable to haemodialysis. Lithium is freely distributed throughout total body water with a volume of distribution between 0.6 to 0.9 L/kg, although the volume may be smaller in the elderly, who have less lean body mass and less total body water. Steady-state serum levels are typically reached within five days at the usual oral dose of 1200 to 1800 mg/day. The half-life for lithium is approximately 18 hours in adults and 36 hours in the elderly.
Lithium is excreted almost entirely by the kidneys and is handled in a manner similar to sodium. Lithium is freely filtered but over 60 percent is then reabsorbed by the proximal tubules. -
This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 4
Correct
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You examine a 34-year-old lady with symptoms that are consistent with acute sinusitis. You're thinking about giving her doxycycline for treatment.
What is doxycycline's mechanism of action?Your Answer: Inhibition of protein synthesis
Explanation:Doxycycline and other tetracycline antibiotics attach to the 30S subunit of the bacterial ribosome, preventing aminoacyl-tRNA binding and so protein synthesis beginning.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 5
Correct
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A 52-year-old patient requires procedural sedation for DC cardioversion of atrial fibrillation. You plan on using propofol as the sedative agent.
Propofol works as a result of action on what type of receptor? Select ONE answer only.Your Answer: Gamma-aminobutyric acid (GABA)
Explanation:Propofol (2,6-diisopropylphenol) is a short-acting phenol derivative that is primarily used for the induction of anaesthesia.
Its mechanism of action is unclear but is thought to act by potentiating the inhibitory neurotransmitters GABA and glycine, which enhances spinal inhibition during anaesthesia.
The dose for induction of anaesthesia is 1.5-2.5mg/kg. The dose for maintenance of anaesthesia is 4-12 mg/kg/hour. Following intravenous injection, propofol acts within 30 seconds and its duration of action is 5-10 minutes.
Propofol produces a 15-25% decrease in blood pressure and systemic vascular resistance without a compensatory increase in heart rate. It is negatively inotropic and decreases cardiac output by approximately 20%.
The main side effects of propofol are:
Pain on injection (in up to 30%)
Hypotension
Transient apnoea
Hyperventilation
Coughing and hiccough
Headache
Thrombosis and phlebitis -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 6
Correct
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Cystic fibrosis patients have a weakened lung surfactant system. Which of the following cell types is in charge of surfactant secretion?
Your Answer: Type II pneumocytes
Explanation:Alveolar type II cells are responsible for four primary functions: surfactant synthesis and secretion, xenobiotic metabolism, water transepithelial transport, and alveolar epithelium regeneration following lung injury.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 7
Correct
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A patient with pronounced tremor, muscle contractions, muscle spasms, and slowness of movement is brought in by his family. He has a long history of mental health issues for which he is currently treated with a variety of medications.
Which of the medications listed below is most likely to be the cause of these side effects?Your Answer: Haloperidol
Explanation:Acute dyskinesias and dystonic reactions, tardive dyskinesia (rhythmic, involuntary movements of the tongue, face, and jaw), Parkinsonism (tremor, bradykinesia, and rigidity), akinesia, akathisia, and neuroleptic malignant syndrome are all examples of extrapyramidal side effects. They are caused by dopamine depletion or blockade in the basal ganglia; this lack of dopamine frequently mimics idiopathic extrapyramidal pathologies.
The first-generation antipsychotics, which are strong dopamine D2 receptor antagonists, are the drugs most commonly associated with extrapyramidal side effects. Haloperidol and fluphenazine are the two drugs in this class that are most commonly associated with extrapyramidal side effects. Extrapyramidal adverse effects are less common in second-generation antipsychotics (e.g., olanzapine) than in first-generation antipsychotics.
Other drugs are linked to extrapyramidal symptoms as well, but at a lower rate. Some antidepressants, lithium, various anticonvulsants, antiemetics, and, in rare cases, oral contraceptive agents are among them.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 8
Incorrect
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A 39-year-old man with a long history of depression presents after intentionally overdoing his heart medication. Verapamil immediate-release 240 mg is the tablet he takes for this condition, he says. He took the pills about 30 minutes ago, but his wife discovered him right away and rushed him to the emergency room.
Which of the following is a verapamil toxicity?Your Answer: Hyperinsulinaemia
Correct Answer: Negative inotropy
Explanation:Overdosing on calcium-channel blockers should always be taken seriously and regarded as potentially fatal. Verapamil and diltiazem are the two most lethal calcium-channel blockers in overdose. These work by binding the alpha-1 subunit of L-type calcium channels, preventing calcium from entering the cell. In cardiac myocytes, vascular smooth muscle cells, and islet beta-cells, these channels play an important role.
The following summarises the toxicity of calcium-channel blockers:
Cardiac effects
Vascular smooth muscle tone affects
Metabolic effects
Excessive negative inotropy: myocardial depression
Negative chronotropy: sinus bradycardia
Negative dromotropy: atrioventricular node blockade
Decreased afterload
Systemic hypotension
Coronary vasodilation
Hypoinsulinaemia
Calcium channel blocker-induced insulin resistance -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 9
Correct
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During her pregnancy, a 28-year-old lady was given an antibiotic. The neonate is born with bilateral deafness as a result of this.
From the following antibiotics, which one is most likely to cause this side effect?Your Answer: Gentamicin
Explanation:Aminoglycosides cross the placenta and are linked to poisoning of the 8th cranial nerve in the foetus, as well as permanent bilateral deafness.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 10
Incorrect
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The following all cause a right shift in the oxygen dissociation curve EXCEPT for:
Your Answer: Decrease in pH
Correct Answer: Foetal haemoglobin
Explanation:A decreased affinity of haemoglobin for oxygen (and hence increased ease of dissociation), shown by a right shift in the oxygen dissociation curve, is caused by a fall in pH, a rise in PCO2(the Bohr effect) and an increase in temperature. These changes occur in metabolically active tissues such as in exercise, and encourage oxygen release. The metabolic by-product 2,3-diphosphoglycerate (2,3 -DPG) also causes a right shift; 2, 3 -DPG may also be raised in chronic anaemia, chronic lung disease, or at high altitude. Foetal haemoglobin (HbF) binds 2, 3 -DPG less strongly than does adult haemoglobin (HbA), and so the HbF dissociation curve lies to the left of that for HbA, reflecting its higher oxygen affinity. This helps transfer oxygen from mother to foetus.
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 11
Correct
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Regarding antimuscarinic antispasmodics, which of the following statements is CORRECT:
Your Answer: They are contraindicated in paralytic ileus.
Explanation:Antimuscarinics are contraindicated in paralytic ileus. Antimuscarinics reduce intestinal motility by blocking muscarinic acetylcholine receptors and relaxing smooth muscle. Hyoscine butylbromide is advocated as a gastrointestinal antispasmodic, but it is poorly absorbed and thus has limited clinical utility. Antimuscarinics cause a reduction in bronchial secretions (they can be used to this effect in palliative patients). Antispasmodics are occasionally of value in treating abdominal cramp associated with diarrhoea but they should not be used for primary treatment. Antispasmodics should be avoided in young children with gastroenteritis because they are rarely effective and have troublesome side effects.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 12
Incorrect
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You're examining a 58-year-old male who has cellulitis in his left leg. Because he is allergic to penicillin, you start him on erythromycin.
Which of the following statements about erythromycin is correct?Your Answer: It can only be administered orally
Correct Answer: It can be used to treat Legionnaire’s disease
Explanation:Bacteriostatic antibiotics include erythromycin and other macrolide antibiotics. They work by attaching to the bacterial ribosome’s 50S subunit, preventing translocation and thereby protein synthesis. Macrolide antibiotics are actively concentrated inside leukocytes and delivered to the infection site as a result.
Erythromycin is an orally active antibiotic that can also be given intravenously. It is metabolized in the liver and eliminated in the bile and has a biological half-life of 1.5 hours.
It has a similar antibacterial spectrum to benzylpenicillin (i.e., a narrow spectrum, primarily against Gram-positive pathogens) and can be used as a penicillin substitute in people who are allergic to penicillin.
Erythromycin is unsuccessful in the treatment of meningitis because it does not penetrate the central nervous system well enough. It is efficient against a variety of unusual pathogens, unlike penicillin. -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 13
Correct
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As part of his angina treatment, a 68-year-old man is prescribed a beta blocker. He starts having nightmares and has trouble sleeping soon after starting the beta-blocker.
Which of the beta blockers listed below is the most likely to be in his system?Your Answer: Propranolol
Explanation:The beta-adrenoceptors in the heart, peripheral vasculature, bronchi, pancreas, and liver are blocked by beta-adrenoceptor blocking drugs (beta blockers).
Beta blockers come in a wide range of strengths, with the choice largely determined by the disease being treated and the patient’s unique circumstances. The intrinsic sympathomimetic activity, lipid solubility, duration of action, and cardioselectivity of beta blockers all differ.
Some beta blockers are lipid (lipophilic) soluble, while others are water soluble (hydrophilic). Drugs that are more lipid-soluble are absorbed faster from the gut, undergo more first-pass metabolism, and are eliminated faster. They’re also more likely to get into the brain and cause central effects like insomnia and nightmares. Propranolol, pindolol, labetalol, and metoprolol are examples of lipid-soluble beta blockers. Beta blockers that are water-soluble are less likely to enter the brain and are more resistant to first-pass metabolism. They are excreted by the kidneys, and in renal impairment, dosage reduction is frequently required. Atenolol, nadolol, celiprolol, and sotalol are examples of water-soluble beta blockers.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 14
Incorrect
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An elderly female with a diagnosed psychiatric illness was prescribed prochlorperazine for her complaints of dizziness and nausea. Two days later, she returned to the clinic with no improvement in the symptoms.
Which one of the following is the mechanism of action of prochlorperazine?Your Answer: Neurokinin receptor antagonism
Correct Answer: Dopamine receptor antagonism
Explanation:Prochlorperazine is a phenothiazine drug as it is categorized as a first-generation antipsychotic. It mainly blocks the D2 (dopamine 2) receptors in the brain. Along with dopamine, it also blocks histaminergic, cholinergic, and noradrenergic receptors.
It exerts its antiemetic effect via dopamine (D2) receptor antagonist. It is used to treat nausea and vomiting of various causes, including labyrinthine disorders.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 15
Incorrect
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A 14-year-old female is brought to the Emergency Room by her mother after a fall from a tree in which she injured her elbow. An elbow fracture is suspected based on the examination findings, and she is given Entonox for analgesia as her elbow is set in a cast.
Which one of the following statements regarding this drug is true?Your Answer: It continues to work for approximately 10 minutes after inhalation has ceased
Correct Answer: It can cause inhibition of vitamin B12 synthesis
Explanation:Entonox is a mixture of 50% Oxygen and 50% nitrous oxide and is given in an inhaled form as a quick form of analgesia. Entonox causes non-competitive inhibition of NMDA (N-methyl-D-aspartate) receptors, which are a subtype of the glutamate receptor.
It is stored in blue and white cylinders and administered via a pressure regulator and demand valve. The administration of this medicine reduces pain and anxiety in paediatric and dental procedures ands during labour.
Effects are apparent after 20 seconds, and peak action occurs after 3 to 5 minutes as it is a drug with a rapid onset and the patient will also recover rapidly from its effects. Entonox is widely used as it does not accumulate in the body and does not cause many side effects. However, a notable side effect is the inhibition of Vitamin B12 synthesis.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 16
Correct
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A critically ill 48-year-old individual appears with symptoms and signs of an anaphylactic reaction.
In an allergic reaction, which of the following is an absolute contraindication to the injection of adrenaline?Your Answer: None of the other options
Explanation:Even if the following relevant contraindications exist, adrenaline can be given in life-threatening anaphylactic reactions:
Coronary artery disease (CAD)
Coronary artery disease (CAD) Second stage of labour
Hypertension that is uncontrolled
Severe Ventricular arrhythmias -
This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 17
Correct
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A 66-year-old female who is a known case of atrial fibrillation comes to the Emergency Department with the complaint of fever and vomiting for the past two days. When her medical chart is reviewed, you see that she takes Warfarin for her arrhythmia.
Which ONE of the following medications cannot be prescribed to this patient?Your Answer: Ibuprofen
Explanation:Like other non-steroidal anti-inflammatory drugs, Ibuprofen cannot be given with Warfarin as it would increase the bleeding risk of this patient.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 18
Incorrect
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A 60-year-old man comes to your department with complaints of epigastric pain. There is a history of rheumatoid arthritis and he has been taking ibuprofen 200 mg TDS for the last 2 weeks.
The following scenarios would prompt you to consider the co-prescription of a PPI for gastroprotection with NSAIDs EXCEPT?
Your Answer: Long-term use for rheumatoid arthritis in a patient aged 30
Correct Answer: Long-term use for chronic back pain in a patient aged 30
Explanation:The current recommendations by NICE suggest that gastro-protection should be considered if patients have ≥1 of the following:
Aged 65 or older
– Using maximum recommended dose of an NSAID
– History of peptic ulcer or GI bleeding
– Concomitant use of: antidepressants like SSRIs and SNRIs, Corticosteroids, anticoagulants and low dose aspirin
– Long-term NSAID usage for: long-term back pain if older than 45 and patients with OA or RA at any ageThe maximum recommended dose of ibuprofen is 2.4 g daily and this patient is on 400 mg of ibuprofen TDS.
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This question is part of the following fields:
- Musculoskeletal Pharmacology
- Pharmacology
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Question 19
Correct
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During her pregnancy, a 28-year-old lady was given an antibiotic. The neonate was prematurely born with cyanosis and ashen grey coloured skin as a result of this. Other symptoms were hypotonia, low blood pressure, and poor feeding.
From the following antibiotics, which one is most likely to cause this side effect?Your Answer: Chloramphenicol
Explanation:Grey baby syndrome is a rare but causes significant adverse effect caused by the build-up of chloramphenicol in neonates (particularly preterm babies).
The following are the main characteristics of ‘grey baby syndrome’:
Skin that is ashy grey in colour.
Feeding problems
Vomiting
Cyanosis
Hypotension
Hypothermia
Hypotonia
Collapse of the cardiovascular system
Distension of the abdomen
trouble breathing -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 20
Correct
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Compliance is decreased by all but which one of the following:
Your Answer: Aging
Explanation:Factors increasing compliance:
Old age
EmphysemaFactors decreasing compliance:
Pulmonary fibrosis
Pulmonary oedema
Atelectasis
Extremes of lung volumes (at higher lung volumes the compliance of the lung becomes less as the lung becomes stiffer) -
This question is part of the following fields:
- Physiology
- Respiratory
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Question 21
Correct
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Intravenous glucose solutions are typically used in the treatment of all of the following situations except:
Your Answer: Hypokalaemia
Explanation:In hypokalaemia, initial potassium replacement therapy should not involve glucose infusions, as glucose may cause a further decrease in the plasma-potassium concentration. Glucose infusions are used for the other indications like diabetic ketoacidosis, hypoglycaemia, routine fluid maintenance in patients who are nil by mouth (very important in children), and in hyperkalaemia.
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This question is part of the following fields:
- Fluids And Electrolytes
- Pharmacology
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Question 22
Correct
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Before a patient is discharged, you are asked to review them. He is a 59-year-old man who was seen with epigastric pain that has since subsided, and he will be seen by his GP in the coming days. He's been hearing a lot about aspirin lately and wants to learn more about it.
Which of the following statements about aspirin's mechanism of action is correct?Your Answer: Inhibition of cyclo-oxygenase
Explanation:Aspirin works by inhibiting cyclo-oxygenase in an irreversible manner, resulting in a decrease in prostaglandin and thromboxane production. As a result, platelet activation and aggregation are reduced.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 23
Incorrect
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An elderly female has a bacterial infection and you are asked to prescribe an antibiotic to her. This antibiotic is a nucleic acid synthesis inhibitor.
Which of the following antimicrobial drugs will be prescribed to this patient?Your Answer: Gentamicin
Correct Answer: Metronidazole
Explanation:Metronidazole and the other 5-nitroimidazole agents inhibit nucleic acid synthesis by forming toxic free radical metabolites in the bacterial cell that damage DNA.
Vancomycin inhibits cell wall peptidoglycan formation by binding the D-Ala-D-Ala portion of cell wall precursors.
Erythromycin inhibits protein synthesis and blocks translocation by binding to the 23S rRNA of the 50S ribosomal subunit.
Chloramphenicol blocks peptidyl transferase at 50S ribosomal subunit.
Gentamicin, an aminoglycoside antibiotic, acts by binding to the 30S subunit of the bacterial ribosome inhibiting the binding of aminoacyl-tRNA and thus preventing initiation of protein synthesis.
An overview of the different mechanisms of action of the various types of antimicrobial agents is shown below:
1. Inhibition of cell wall synthesis
– Penicillins
– Cephalosporins
– Vancomycin
2. Disruption of cell membrane function
– Polymyxins
– Nystatin
– Amphotericin B
3. Inhibition of protein synthesis
– Macrolides
– Aminoglycosides
– Tetracyclines
– Chloramphenicol
4. Inhibition of nucleic acid synthesis
– Quinolones
– Trimethoprim
– 5-nitroimidazoles
– Rifampicin
5. Anti-metabolic activity
– Sulphonamides
– Isoniazid -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 24
Incorrect
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In the Emergency Department, a 35-year-old woman actively seizing is brought in. She is quickly shifted into the resuscitation room and is administered a dose of benzodiazepine. The seizure is quickly terminated.
Once the patient is stable, she tells you she is a known case of epilepsy and takes phenytoin to control it.
Which of the following is the primary mechanism of action of phenytoin?Your Answer: Glutamate blocker
Correct Answer: Sodium channel blocker
Explanation:Phenytoin is in the anticonvulsants class of drugs and is used in the management and treatment of the following:
1. epilepsy
2. generalized tonic-clonic seizures
3. complex partial seizures
4. status epilepticus.It works by inactivating the voltage-gated sodium channels responsible for increasing the action potential. It is non-specific and targets almost all voltage-gated sodium channel subtypes. More specifically, phenytoin prevents seizures by inhibiting the positive feedback loop that results in neuronal propagation of high-frequency action potentials.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 25
Correct
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A 58-year-old male has cellulitis of his left leg. Because he is allergic to penicillin, you start him on erythromycin.
What is erythromycin's mechanism of action?Your Answer: Inhibition of protein synthesis
Explanation:Bacteriostatic antibiotics include erythromycin and other macrolide antibiotics. They work by attaching to the bacterial ribosome’s 50S subunit, preventing translocation and thereby protein synthesis. Macrolide antibiotics are actively concentrated inside leukocytes and delivered to the infection site as a result.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 26
Correct
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A 36 year old man who is overweight with a history of gout, presents to emergency room with an acutely painful big toe which is red, hot and swollen. However, he is apyrexic and otherwise systemically well. He has been diagnosed with acute gout. The most appropriate first line treatment for him is which of the following?
Your Answer: NSAIDs
Explanation:The first line treatment for acute gout includes NSAIDs like diclofenac, indomethacin or naproxen. In patients in whom NSAIDs are contraindicated, not tolerated or ineffective, colchicine is an alternative. In those who cannot tolerate or who are resistant to NSAIDs and colchicine, oral or parenteral corticosteroids are an effective alternative. In acute monoarticular gout, intra-articular injection of a corticosteroid can be used occasionally. In acute gout. allopurinol is not used in the actual treatment, but its use should be continued during an acute attack if the patient is already established on long term therapy.
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This question is part of the following fields:
- Musculoskeletal
- Pharmacology
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Question 27
Incorrect
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In a ward round, you come across a patient's treatment chart prescribed an antibiotic to fight his infection. This antibiotic is an inhibitor of cell wall synthesis.
Which of the following antimicrobial drugs is prescribed to this patient?Your Answer: Isoniazid
Correct Answer: Benzylpenicillin
Explanation:Penicillins and cephalosporins are the major antibiotics that inhibit bacterial cell wall synthesis. They inactivate transpeptidases that help cross-link peptidoglycans in cell walls.
Isoniazid decreases the synthesis of mycolic acids in mycobacterium.
Clarithromycin binds to the 50S subunit of ribosomes and inhibits protein synthesis.
Metronidazole and the other 5-nitroimidazole agents inhibit nucleic acid synthesis by forming toxic free radical metabolites in the bacterial cell that damage DNA.
Tetracycline bind to 30S and prevent attachment of aminoacyl-tRNA.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 28
Incorrect
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In a VF arrest, a 6-year-old child is brought to your Emergency Department resuscitation area. He weighs 16 kilogrammes. He's had three DC shocks, but he's still in VF and doesn't have an output.
What amiodarone dose should he get now, according to the most recent APLS guidelines?Your Answer: 32 mg
Correct Answer: 80 mg
Explanation:In a shockable (Vf/pVT) paediatric cardiac arrest, amiodarone should be administered after the third and fifth shocks. The dose is 5 mg/kg (maximum 300 mg) and should be administered over a three-minute period. If at all possible, administration via a central line is recommended.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 29
Incorrect
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A 25-year-old patient requires procedural sedation for reduction of an open fracture of his tibia and fibula. You plan on using ketamine as the sedative agent.
Ketamine works as a result of action on what type of receptor? Select ONE answer only.Your Answer: Gamma-aminobutyric acid (GABA)
Correct Answer: N-methyl-D-aspartate (NMDA)
Explanation:Ketamine is the only anaesthetic agent available that has analgesic, hypnotic, and amnesic properties. When used correctly it is a very useful and versatile drug.
Ketamine acts by non-competitive antagonism of the NMDA receptor Ca2+ channel pore and also inhibits NMDA receptor activity by interaction with the phencyclidine binding site.
Ketamine can be used intravenously and intramuscularly. The intramuscular dose is 10 mg/kg, and when used by this route, it acts within 2-8 minutes and has a duration of action of 10-20 minutes. The intravenous dose is 1.5-2 mg/kg administered over a period of 60 seconds. When used intravenously, it acts within 30 seconds and has a duration of action of 5-10 minutes. Ketamine is also effective when administered orally, rectally, and nasally.
Ketamine causes tachycardia, an increase in blood pressure, central venous pressure, and cardiac output, secondary to an increase in sympathetic tone. Baroreceptor function is well maintained, and arrhythmias are uncommon.
The main disadvantage to the use of ketamine is the high incidence of hallucinations, nightmares, and other transient psychotic effects. These can be reduced by the co-administration of a benzodiazepine, such as diazepam or midazolam.
The main side effects of ketamine are:
Nausea and vomiting
Hypertension
Nystagmus
Diplopia
Rash -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 30
Incorrect
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Regarding gas exchange at the alveolar-capillary membrane, which of the following statements is CORRECT:
Your Answer: Rate of diffusion is primarily dependent on the alveolar-capillary concentration gradient of O 2 and CO 2 .
Correct Answer: The rate of diffusion in lungs can be estimated by measuring the diffusing capacity of the lungs for carbon monoxide.
Explanation:Gas exchange between alveolar air and blood in the pulmonary capillaries takes place by diffusion across the alveolar-capillary membrane. Diffusion occurs from an area of high partial pressure to an area of low partial pressure, thus the driving force for diffusion is the alveolar-capillary partial pressure gradient. Diffusion occurs across a membrane and is therefore governed by Fick’s law. Although CO2is larger than O2, it is is much more soluble and diffuses 20 times more rapidly. The diffusing capacity for oxygen (DLO2) cannot be measured directly but the rate of diffusion in the lungs can be estimated by measuring the diffusing capacity of the lungs for carbon monoxide (DLCO).
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This question is part of the following fields:
- Physiology
- Respiratory
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SESSION STATS - PERFORMANCE PER SPECIALTY
