Context-sensitive half-time drugs

Drugs which have a context-sensitive half-time which increases with time include

(a) remifentanil

(b) alfentanil

(c) fentanyl

(d) propofol

(e) morphine

Omeprazole

Omeprazole

(a) is a pro-drug

(b) acts by blocking histamine (H2) receptors

(c) is longer acting than cimetidine

(d) has a rapid onset of action

(e) is effective in Zollinger–Ellison syndrome

Doxapram

Doxapram

(a) acts by stimulating peripheral chemoreceptors

(b) is contraindicated in epilepsy

(c) interacts with aminophylline

(d) reduces systolic arterial blood pressure

(e) is a competitive antagonist at the mu receptor

Intravenous mannitol

Intravenous mannitol

(a) is a polyhydric alcohol

(b) is used as a fuel substrate for most cells in the body

(c) extravasations can cause tissue necrosis

(d) causes haemolysis

(e) can cause a delayed increase in cranial pressure

Adenosine

Adenosine

(a) is used to reduce atrioventricular conduction in the treatment of supraventricular  achyarrhythmias

(b) may cause bronchospasm

(c) has a long elimination half-time

(d) is a potent coronary vasodilator

(e) is contraindicated in heart block

Epinephrine

 Injection of intramuscular or intravenous epinephrine causes

(a) increased pulmonary artery systolic pressure

(b) increased pulmonary blood flow

(c) increased pulmonary artery wedge pressure

(d) no change in pulmonary artery pressure

(e) an increase in diastolic blood pressure

Angiotensin Converting Enzyme Inhibitors (ACEI)

Angiotensin converting enzyme inhibitors (ACEI)

(a) reduce arteriolar tone more than venous tone

(b) cause renal impairment in patients with renal artery stenosis

(c) cause troublesome cough

(d) are used to treat pregnancy-induced hypertension

(e) cause hypokalaemia

Gastric emptying time

The following drugs increase the gastric emptying time

(a) ranitidine

(b) domperidone

(c) morphine

(d) neostigmine

(e) glycopyrrolate

Class 1a anti-arrhythmic drugs

Class 1a anti-arrhythmic drugs usually

(a) slow depolarisation

(b) increase the threshold potential

(c) increase the action potential

(d) are indicated for atrial arrhythmias

(e) have local anaesthetic activity

Potentiation of neuromuscular block by neomycin

Potentiation of neuromuscular block by neomycin is

(a) more likely with a non-depolarising block than with a depolarising block

(b) intensified by enflurane

(c) lessened by the administration of calcium

(d) antagonised by the administration of neostigmine

(e) increased by simultaneously administering trimethoprim

Neostigmine

Neostigmine

(a) is a tertiary amine

(b) is metabolised in the liver

(c) may prolong the action of suxamethonium

(d) inhibits both cholinesterase and pseudocholinesterase

(e) if given during pregnancy can cause fetal muscle weakness

Midazolam vs diazepam

Midazolam when compared with diazepam

(a) is more lipid soluble

(b) produces longer-acting active metabolites

(c) causes less discomfort on injection

(d) has a significantly lower volume of distribution

(e) has a shorter elimination half-life

Flumazenil

Flumazenil

(a) is a competitive benzodiazepine antagonist

(b) is an inverse agonist at the benzodiazepine receptor

(c) has a relatively short half-life

(d) is useful in treating hepatic encephalopathy

(e) is indicated in status epilepticus

5HT3 blockers

The following are 5HT3 blockers

(a) octreotide

(b) methysergide

(c) cyproheptadine

(d) ketanserine

(e) ondansetron

Naloxone

Naloxone

(a) is a kappa receptor agonist

(b) has a high oral bioavailability

(c) has an elimination half-life of 1–2 h

(d) causes pulmonary oedema

(e) prevents conversion of angiotensin I to angiotensin II

Mechanisms of Opioid Action

Which of the following are true of the mechanisms of opioid action?

(a) there are currently five separate opioid receptors

(b) the mu („) receptor has been classified as the op1 receptor

(c) opioid receptors are found at peripheral sites

(d) buprenorphine is a partial agonist at the mu („) receptor

(e) nalbuphine is an effective mu („) receptor antagonist

Lidocaine (lignocaine)

Lidocaine (lignocaine)

(a) prolongs the duration of action of the cardiac action potential

(b) inhibits plasma cholinesterase

(c) causes sedation

(d) causes atrioventricular block

(e) has a high hepatic extraction ratio

Prilocaine

Prilocaine

(a) has a pKa of 5.0

(b) has a longer duration of action than lidocaine

(c) is metabolised by plasma cholinesterase

(d) has a higher pKa than bupivacaine

(e) is more protein bound than bupivacaine

Etomidate

Etomidate

(a) reduces intraocular pressure

(b) is solubilised in propylene glycol

(c) causes a higher incidence of venous sequelae than thiopentone

(d) reduces plasma cortisol concentrations by an action on the pituitary gland

(e) is excreted unchanged in the kidney

Dystonic Reactions

The following cause dystonic reactions

(a) ondansetron

(b) metoclopramide

(c) cyclizine

(d) prochlorperazine

(e) domperidone

Induction of Anaesthesia

The following speed up the induction of anaesthesia with volatile anaesthetics

(a) use of CO2

(b) increased cardiac output

(c) agents with a high blood/gas solubility coefficient

(d) increased alveolar ventilation

(e) hypotension

Direct Sympathetic Stimulation

The following anaesthetic agents cause direct sympathetic stimulation

(a) enflurane

(b) sevoflurane

(c) desflurane

(d) halothane

(e) isoflurane

Cytochrome P450

The following drugs induce the enzyme cytochrome P450

(a) carbamazepine

(b) nitrazepam

(c) metronidazole

(d) ranitidine

(e) rifampicin

Drug structure alteration

pH alters the structure of the following drugs

(a) diazepam

(b) midazolam

(c) lidocaine

(d) atracurium

(e) suxamethonium

Drug diffusion

The following factors enhance the diffusion of a drug across the blood-brain barrier

(a) high plasma protein binding

(b) high degree of ionisation at physiological pH

(c) high molecular weight

(d) high lipid solubility

(e) high plasma–brain concentration gradient

Drug absorbtion

The following drugs are well absorbed from the stomach

(a) morphine

(b) diamorphine

(c) midazolam

(d) loperamide

(e) propranolol

Drugs metabolism

The following drugs are extensively metabolised

(a) prilocaine

(b) digoxin

(c) chlorpromazine

(d) diazepam

(e) paracetamol

Drug Receptors

The following statements are true regarding drug receptors

(a) they are found only in cell membranes

(b) drug receptor activity is always G-protein-coupled

(c) the concentration of receptors in the cell membranes is dynamic

(d) GABA receptors are ligand-gated ion channels

(e) competitive antagonists bind reversibly to the receptors

Motility of the Gastrointestinal Tract

The motility of the gastrointestinal tract is increased by

(a) vagotomy

(b) complete transection of the spinal cord at T3

(c) stellate ganglion block

(d) mechanical bowel obstruction

(e) neostigmine

Plasma proteins

Plasma proteins

(a) exert an osmotic pressure of approximately 5.3 kPa (40 mmHg)

(b) provide one-half of the buffering capacity of the blood

(c) include plasminogen

(d) are mostly in the anionic form

(e) are the main source of carbamino groups

Athletes

When compared to normal people athletes have

(a) a larger stroke volume at rest

(b) a lower heart rate at any given level of exercise

(c) a decreased maximal oxygen consumption (V_O2 max)

(d) a smaller increase in blood lactate production with exercise

(e) a higher muscle blood flow

Renal Tubule

In the renal tubule

(a) hydrogen ions are excreted in combination with ammonia

(b) hydrogen ions are excreted mostly as phosphate

(c) aldosterone increases sodium absorption in the distal convoluted tubule (DCT) and collecting duct

(d) ADH increases water permeability in the DCT

(e) almost 99% of the glomerular filtrate is reabsorbed

Compensatory reactions activated by haemorrhage

Compensatory reactions activated by haemorrhage include

(a) decreased movement of interstitial fluid into the capillaries

(b) decreased plasma protein synthesis

(c) increased secretion of ADH

(d) decreased glomerular filtration rate

(e) decreased filtration fraction

Respiratory Quotient (RQ)

The respiratory quotient (RQ)

(a) is the ratio of CO2 to O2 at any given time

(b) is the ratio in the steady-state of the volume of CO2 produced to the volume of O2 consumed per unit of time

(c) is 0.7 with a diet of carbohydrate

(d) is decreased during hyperventilation

(e) increases during severe exercise

Aldosterone

Aldosterone

(a) does not directly affect renal blood flow

(b) increases the acidity of urine

(c) reduces the sodium content of sweat

(d) potentiates the effects of vasopressin in hypovolaemia

(e) is excreted in response to angiotensin

Vomiting Reflex

With regard to the vomiting reflex the

(a) diaphragm relaxes

(b) glottis opens

(c) epiglottis closes

(d) oesophageal sphincter closes

(e) respiration stops

Chemoreceptor Trigger Zone (CTZ)

The following receptors are present in the chemoreceptor  trigger zone (CTZ)

(a) opioid

(b) dopaminergic D1 receptors

(c) muscarinic M3 receptors

(d) adrenergic fi1 and fi2

(e) serotogenic 5HT3

Erythropoietin

Erythropoietin

(a) is a circulating hormone without which hypoxia has little or no effect on red cell production

(b) is formed in the kidney and in the liver

(c) production is stimulated by epinephrine and norepinephrine

(d) production is increased within minutes of the development of hypoxia

(e) activity is decreased when the red cell volume is increased

Delta waves on the EEG

Delta waves on the EEG are associated with

(a) hypoxia

(b) hypercarbia

(c) sleep

(d) closing eyes

(e) deep general anaesthesia

Fetal Circulation

In the fetal circulation the

(a) foramen ovale closes due to pressure change

(b) ductus venosus carries mixed venous blood

(c) blood can reach the aorta from the superior vena cava without passing through the left atrium or the left ventricle

(d) saturation of fetal haemoglobin (Hb F) in the descending aorta is more than in the aortic arch

(e) oxygen saturation in the umbilical vein is 45%

Starvation period

During periods of starvation in humans

(a) glycogen stores are depleted in 24 h

(b) amino acids are converted to glucose

(c) tissue breakdown initially provides 900 calories per day

(d) urinary nitrogen loss progressively increases

(e) a loss of 40% body cell mass is compatible with survival

Normal excretion after major surgery

Following major surgery a young fit 70-kg man will normally excrete, in 24 h

(a) 500 ml water

(b) 30 mmol Naþ

(c) 10 mmol Kþ

(d) 20 mmol urea

(e) 10 mmol Cl_

Stretch Reflex

The stretch reflex

(a) consists of only one synapse within the central nervous system

(b) involves gamma motor fibres as the efferent link

(c) causes jerkiness of body movements

(d) involves glutamate as a neurotransmitter at the central synapse

(e) is highly facilitated in a decerebrate animal

Proximal Convoluted Tubules (PCT)

Concerning the transport process in the proximal convoluted tubules (PCT)

(a) about 50% of the normal filtered load of HCO3 ion is absorbed in the proximal tubule

(b) absorption of glucose is linked to sodium reabsorption

(c) normally most of the phosphate filtered is excreted

(d) there are active secretory mechanisms for penicillin and para-aminohippuric acid (PAH)

(e) amino acid absorption is independent of sodium reabsorption

Cerebrospinal fluid

Cerebrospinal fluid

(a) is formed by the choroid plexus

(b) has a specific gravity of 1030 at body temperature

(c) total volume in a 70-kg adult is 500 ml

(d) normal pressure in the lateral position is 70–150 kPa

(e) total protein content is more than that of serum proteins

pressure volume curve

A pressure volume curve can be used for measuring

(a) the work of breathing

(b) compliance

(c) functional residual capacity (FRC)

(d) respiratory quotient

(e) anatomical dead space

Individual in lateral position

In an awake, healthy individual assuming the lateral position the 

(a) dependent lung has less ventilation

(b) dependent lung has more perfusion

(c) V_ /Q_ ratio is higher in the dependent lung

(d) PO2 is higher in the lower lung

(e) PaCO2 is lower in the lower lung

Loop of Henle

The ascending limb of the loop of Henle

(a) is impermeable to sodium

(b) is involved in the active transport of potassium ions into the lumen

(c) is involved in the transport of chloride out of the lumen

(d) actively transports water

(e) contains hypotonic urine at the distal end

Functional residual capacity (FRC)

Functional residual capacity (FRC)

(a) measurement by the helium dilution technique gives a

higher value than that given by body plethysmography

(b) is equal to total lung capacity minus the reserve volume

(c) is increased by changing from the erect to the supine posture

(d) is reduced during pregnancy

(e) is decreased in old age

Alveolar

Alveolar dead space is increased in

(a) pulmonary embolism

(b) haemorrhage

(c) increased tidal volumes

(d) changing from the supine to the erect posture

(e) intermittent positive-pressure ventilation

Normal inspiration

During normal inspiration there is an increase in

(a) intrapleural pressure

(b) alveolar pressure

(c) intra-abdominal pressure

(d) the relative humidity of air in the trachea

(e) the partial pressure of oxygen in the trachea

Lung compliance

Lung compliance

(a) describes the relationship between pressure and flow

(b) decreases with age

(c) is reduced in the supine position

(d) is normally 1.5–2.0 l/kPa

(e) is related to body

Baroreceptors

Concerning baroreceptors

(a) they are located in the carotid sinus and aortic arch

(b) they are stretch receptors

(c) the neuronal discharge decreases as the mean arterial pressure increases

(d) the neuronal firing increases as the heart rate increases

(e) baroreceptors in the carotid sinus are more sensitive

than aortic receptors to changes in blood pressure

Pulmonary vascular resistance

Pulmonary vascular resistance is

(a) increased when the haematocrit is abnormally high

(b) decreased when breathing 21% oxygen in 79% helium

(c) increased by the application of 5 cmH2O positive

end-expiratory pressure

(d) increased by hypercapnia

(e) decreased by moderate exercise

Normal ECG

In the normal ECG the

(a) Q wave is normally present in lead V6

(b) T wave is normally inverted in aVR

(c) Q wave is normally present in V1

(d) R wave is larger than the S wave in V1

(e) QRS duration depends on the recording electrode

Fetal haemoglobin

Fetal haemoglobin

(a) forms 60% of circulating haemoglobin at birth

(b) is normally replaced by haemoglobin A (HbA) within

6–9 months

(c) has a sigmoid-shaped dissociation curve

(d) has a greater oxygen content at any given PO2 than adult

haemoglobin

(e) binds 2,3-DPG more avidly than HbA

Myocardial work

Myocardial work increases when there is an increase in

(a) stroke volume

(b) ventricular systolic pressure

(c) contractility

(d) heart rate

(e) systemic vascular resistance

Pulse pressure

Pulse pressure

(a) is the median value between the systolic and the diastolic

blood pressures

(b) is reduced during tachycardia

(c) is determined by the compliance of the arterial tree

(d) decreases in old age

(e) at a given time is the same throughout the arterial tree

Haemophilia

A 31-year-old male with known haemophilia A presents with a fracture of his left

tibia sustained while playing football. The orthopaedic surgeons propose operative

application of an external fixation frame. The patient is unable to grade the severity of

his haemophilia but has had two knee haemarthroses in the previous seven years. As

part of the preoperative preparation of this patient, which one of the following should

be administered intravenously?

a) Fresh frozen plasma

b) Cryoprecipitate

c) Recombinant factor VIII concentrate

d) Recombinant factor IX concentrate

e) Desmopressin