Respiratory and allergy drugs: Practice MCQs

A three-month-old infant is brought to a rural clinic with vomiting, and a relative suggests a promethazine syrup left over from an older sibling. What is the correct response?

1. Promethazine must not be used at this age because of potentially fatal respiratory depression
2. Promethazine is acceptable if the amount is halved for body weight
3. Promethazine is acceptable provided the infant is observed for one hour
4. Promethazine is acceptable because syrups are safer than tablets

Which single property best explains why diphenhydramine causes sedation while fexofenadine does not?

1. Penetration of the central nervous system
2. Affinity for the H1 receptor
3. Duration of receptor occupancy
4. Selectivity for H2 over H1 receptors

A patient taking fexofenadine for hay fever reports that it seems to have stopped working since they began a morning routine of indigestion remedy and a glass of orange juice. What is the most likely explanation?

1. Reduced absorption caused by both the antacid and the fruit juice
2. Rapid tolerance at the H1 receptor
3. Induction of hepatic metabolism by orange juice
4. Displacement of fexofenadine from plasma protein binding

Which antihistamine is contraindicated in a patient with a prolonged QT interval?

1. Hydroxyzine
2. Loratadine
3. Chlorphenamine
4. Ketotifen eye drops

An 82-year-old man with benign prostatic enlargement asks about an over-the-counter tablet for occasional sleeplessness that contains diphenhydramine. Which concern is most relevant?

1. Antimuscarinic effects and sedation are both more troublesome at his age
2. Diphenhydramine has no effect on the bladder
3. The tablet contains no antihistamine because it is sold as a sleep aid
4. Sedation is the only recognised problem in older people

Which statement about second-generation antihistamines and the central nervous system is best supported by the product labels?

1. Animal studies show little or no crossing of the blood-brain barrier, and one label calls the clinical significance unknown
2. Human imaging has proved that no drug of the group enters the brain
3. They enter the brain freely but lack activity at central H1 receptors
4. They are converted in the brain to inactive metabolites

A driver taking a sedating antihistamine says he feels perfectly alert. How should that self-assessment be weighed?

1. It is unreliable, because measurable impairment can occur without obvious drowsiness
2. It is reliable, because drowsiness always precedes impairment
3. It is reliable if he has taken the drug before without incident
4. It is unreliable only if he has also drunk alcohol

According to the current single-ingredient salmeterol label, what is the status of using a long-acting beta-2 agonist for asthma without a concomitant inhaled corticosteroid?

1. Contraindicated
2. Permitted at the lowest effective dose
3. Permitted only in adults over 65
4. Permitted for up to twelve weeks

A patient using an inhaled short-acting beta-2 agonist reports needing it far more often than previously. What does the labelling say this represents?

1. A marker of deteriorating asthma requiring reassessment of the regimen
2. Expected tolerance at the beta-2 receptor
3. Evidence that the device is being used incorrectly
4. A normal seasonal fluctuation requiring no action

Which mechanism do the labels give for hypokalaemia caused by beta-2 agonists?

1. Intracellular shunting of potassium
2. Increased renal potassium excretion through aldosterone
3. Reduced gastrointestinal potassium absorption
4. Chelation of potassium in plasma

Immediately after taking an inhaled beta-2 agonist a patient becomes acutely more wheezy and breathless. What does the label direct?

1. Treat at once with an inhaled short-acting bronchodilator, discontinue the agent and institute alternative therapy
2. Repeat the same inhaler at double the number of actuations
3. Continue the agent and add an oral antihistamine
4. Withhold all bronchodilators and observe

Why is a non-selective beta blocker a particular problem in a patient with asthma taking salbutamol?

1. It blocks the pulmonary effect of the agonist and may itself produce severe bronchospasm
2. It accelerates hepatic clearance of the agonist
3. It prevents absorption of the agonist from the airway
4. It converts the agonist into an inactive metabolite

Which finding best illustrates that the inhaled route lowers the systemic burden of a beta-2 agonist?

1. Tremor is reported in 20% of patients on oral salbutamol tablets but does not reach the 3% adverse reaction table for the inhalation aerosol
2. The inhaled product has a longer duration of action than the oral product
3. The inhaled product is contraindicated in cardiac disease while the oral product is not
4. The oral product acts locally in the lung

Which statement about the once-daily agents indacaterol and olodaterol is correct?

1. Their single-ingredient products are licensed for chronic obstructive pulmonary disease and are not indicated for asthma
2. They are licensed as rescue therapy for acute bronchospasm
3. They are licensed for asthma as monotherapy in adults
4. They act at beta-1 rather than beta-2 receptors

Which combination is specifically flagged as potentiating the hypokalaemic effect of a beta-2 agonist?

1. Xanthine derivatives, steroids or non-potassium-sparing diuretics
2. Proton pump inhibitors and antacids
3. Potassium-sparing diuretics and angiotensin receptor blockers
4. Oral anticoagulants and statins

A patient with asthma develops acute breathlessness and audible wheeze. Which statement about their inhaled corticosteroid is correct?

1. It has no role in relieving the acute episode and a short-acting bronchodilator is required
2. Doubling the number of puffs will produce bronchodilation within minutes
3. It relaxes airway smooth muscle faster than a beta-2 agonist
4. It is licensed specifically for the relief of acute bronchospasm

Why do the labels for these inhalers direct that the mouth is rinsed with water without swallowing after each dose?

1. To help reduce the risk of oropharyngeal candidiasis
2. To prevent tooth enamel erosion from the propellant
3. To improve absorption of the drug from the lung
4. To avoid an unpleasant taste that reduces adherence

A child on a long-term inhaled corticosteroid is reviewed in clinic. Which monitoring do the labels specifically direct?

1. Routine measurement of growth, for example by stadiometry
2. Annual bone marrow examination
3. Three-monthly serum potassium
4. Routine pulmonary function testing after each dose

A patient taking fluticasone propionate is started on ritonavir. What is the principal concern?

1. Raised systemic fluticasone exposure causing Cushing's syndrome and adrenal suppression
2. Loss of asthma control from accelerated fluticasone clearance
3. Precipitation of acute bronchospasm on first dose
4. Irreversible reduction in inhaler device output

Which adverse effect is characteristic of the intranasal rather than the orally inhaled route?

1. Nasal septal perforation
2. Dysphonia
3. Oropharyngeal candidiasis
4. Cough on inhalation

In which population have regulators specifically advised vigilance for pneumonia during treatment with inhaled medicines containing a steroid?

1. Patients with chronic obstructive pulmonary disease
2. Children with seasonal allergic rhinitis
3. Adults using a nasal spray for vasomotor rhinitis
4. Patients after surgical removal of nasal polyps

Which of these correctly describes beclometasone dipropionate?

1. A prodrug rapidly hydrolysed to the active monoester 17-monopropionate
2. An active drug cleared solely by renal excretion of unchanged parent
3. A long-acting beta-2 agonist used for symptom relief
4. A leukotriene receptor antagonist taken by mouth

By what mechanism does ipratropium widen the airway, according to its label?

1. It antagonises acetylcholine and inhibits vagally mediated reflexes in the lung
2. It stimulates beta-2 adrenoceptors on bronchial smooth muscle
3. It inhibits phosphodiesterase and raises intracellular cyclic AMP
4. It blocks cysteinyl leukotriene receptors in the airway wall

A patient receiving nebulised ipratropium by loosely fitting face mask develops eye pain, blurred vision and a red eye. What does the label identify as the risk?

1. Precipitation or worsening of narrow-angle glaucoma from solution reaching the eye
2. Corneal deposits caused by systemic accumulation of the drug
3. Retinal toxicity proportional to cumulative inhaled exposure
4. Optic neuritis as a hypersensitivity reaction

Which pharmacokinetic figure best explains why tiotropium is a once-daily maintenance agent while ipratropium is not?

1. A terminal half-life of approximately 25 hours in COPD, against about two hours for ipratropium
2. Greater oral bioavailability of tiotropium after swallowing the inhaled fraction
3. Higher protein binding of ipratropium in plasma
4. Faster hepatic clearance of tiotropium by cytochrome P450 enzymes

Which history most directly warrants caution before an inhaled antimuscarinic is started?

1. Bladder-neck obstruction due to prostatic hyperplasia
2. Well-controlled hypothyroidism
3. Previous deep vein thrombosis
4. Mild iron-deficiency anaemia

An inhaled antimuscarinic produces immediate wheeze and worsening breathlessness after a dose. What do the labels describe?

1. Paradoxical bronchospasm, which may be life threatening
2. An expected transient effect that settles with continued dosing
3. Tachyphylaxis at the muscarinic receptor
4. Rebound cholinergic tone from receptor upregulation

Which statement about tiotropium and asthma is correct?

1. The soft-mist inhaler is indicated for once-daily maintenance treatment of asthma from six years of age
2. It is indicated as a reliever inhaler for acute asthma symptoms
3. It has no asthma indication in any formulation
4. It replaces inhaled corticosteroid maintenance therapy in asthma

Why does an inhaled antimuscarinic cause fewer systemic anticholinergic effects than an oral one?

1. It is a quaternary ammonium compound that is poorly absorbed, so the effect is local and site-specific
2. It is rapidly destroyed by esterases in plasma before reaching any receptor
3. It binds irreversibly to airway receptors and cannot dissociate into the circulation
4. It is actively pumped back into the airway lumen by efflux transporters

Which statement best describes how zileuton differs mechanistically from montelukast?

1. Zileuton inhibits 5-lipoxygenase and so reduces formation of the leukotrienes, whereas montelukast blocks the CysLT1 receptor
2. Zileuton blocks the CysLT1 receptor more selectively than montelukast does
3. Zileuton is a bronchodilator acting at beta-2 adrenoceptors
4. Zileuton inhibits cyclo-oxygenase and reduces prostaglandin formation

A prescriber is considering montelukast purely for seasonal allergic rhinitis in a patient whose symptoms are mild and who has not tried anything else. What does the labelling require?

1. Use is reserved for patients with an inadequate response or intolerance to alternative therapies
2. Montelukast is the preferred first choice for all allergic rhinitis
3. Montelukast may be used first provided liver enzymes are checked monthly
4. Allergic rhinitis is not an indication for montelukast at any point

Which monitoring requirement belongs specifically to zileuton?

1. Serum ALT before treatment, monthly for the first three months, then every two to three months for the rest of the first year
2. Prothrombin time measured before every dose
3. Annual eosinophil count in all patients
4. Serum potassium at each review

Which of these interactions is documented for zafirlukast?

1. A clinically significant increase in prothrombin time when given with warfarin
2. Loss of oral contraceptive efficacy through enzyme induction
3. A doubling of digoxin clearance
4. Precipitation of serotonin syndrome with selective serotonin reuptake inhibitors

A patient stable on oral theophylline is admitted and stops smoking. One week later he is nauseated, tremulous and tachycardic. What is the most likely explanation?

1. Loss of smoking-induced enzyme activity has reduced theophylline clearance
2. Nicotine withdrawal alone accounts for all of the findings
3. Reduced gastrointestinal absorption has lowered the concentration
4. Theophylline has begun to induce its own metabolism

Which statement best reflects what the theophylline label says about the drug's mechanism of action?

1. The mechanisms are not known with certainty, with animal studies suggesting phosphodiesterase III and IV inhibition
2. Bronchodilation is proven to result from adenosine A1 receptor antagonism
3. The drug acts as a direct beta-2 adrenoceptor agonist on airway smooth muscle
4. It works entirely through inhibition of leukotriene synthesis

Which co-prescribed antibiotic carries a specific labelled warning about serious and fatal reactions when given with theophylline?

1. Ciprofloxacin
2. Amoxicillin
3. Azithromycin
4. Co-trimoxazole

In which pair of conditions does the theophylline label describe clearance as decreased by 50% or more?

1. Congestive heart failure and hepatic insufficiency
2. Hyperthyroidism and cystic fibrosis
3. Renal impairment in adults and hypertension
4. Iron deficiency anaemia and obesity

Which methylxanthine is licensed for the short-term treatment of apnoea of prematurity?

1. Caffeine citrate
2. Aminophylline
3. Pentoxifylline
4. Theophylline extended-release tablets

Which electrolyte abnormality was recorded in the large majority of acute theophylline overdose cases in the series tabulated in the label?

1. Hypokalaemia
2. Hypernatraemia
3. Hypocalcaemia
4. Hyperkalaemia