PSI Clinical Therapeutics — Questions and Answers
Question 1: What is the mechanism of action of proton pump inhibitors (PPIs) such as omeprazole?
- They irreversibly inhibit the hydrogen-potassium ATPase enzyme (proton pump) in gastric parietal cells, reducing gastric acid secretion (Correct answer)
- They neutralise existing stomach acid
- They coat the stomach lining to protect it
- They speed up gastric emptying
Correct answer: They irreversibly inhibit the hydrogen-potassium ATPase enzyme (proton pump) in gastric parietal cells, reducing gastric acid secretion
PPIs work by irreversibly binding to the H+/K+-ATPase enzyme system (the proton pump) on the surface of gastric parietal cells. This blocks the final step of acid production, providing potent and long-lasting suppression of gastric acid secretion.
Question 2: A patient is prescribed warfarin. Which of the following interactions should the pharmacist be most concerned about?
- Concurrent use of NSAIDs such as ibuprofen, which increases the risk of bleeding (Correct answer)
- Taking the warfarin with food
- Drinking water with the medication
- Taking warfarin in the morning versus evening
Correct answer: Concurrent use of NSAIDs such as ibuprofen, which increases the risk of bleeding
NSAIDs increase bleeding risk with warfarin through multiple mechanisms: they inhibit platelet function, can cause GI erosion, and some (like fluconazole) inhibit CYP2C9, which metabolises warfarin. Pharmacists should counsel patients about avoiding OTC NSAIDs and reporting any signs of bleeding.
Question 3: What is the first-line treatment for mild-to-moderate community-acquired pneumonia in adults in Ireland?
- Amoxicillin (Correct answer)
- Ciprofloxacin
- Metronidazole
- Flucloxacillin
Correct answer: Amoxicillin
According to Irish antibiotic prescribing guidelines, amoxicillin is the first-line treatment for community-acquired pneumonia in adults. For penicillin-allergic patients, doxycycline or clarithromycin are alternatives. This follows antimicrobial stewardship principles.
Question 4: What counselling points should a pharmacist provide to a patient starting a statin (e.g., atorvastatin)?
- Take at the recommended time, report unexplained muscle pain, have liver function monitored, avoid grapefruit juice in large quantities, and understand it is for long-term use (Correct answer)
- No counselling is needed for statins
- Tell them to stop taking it if they feel fine after a month
- Only tell them to take it with food
Correct answer: Take at the recommended time, report unexplained muscle pain, have liver function monitored, avoid grapefruit juice in large quantities, and understand it is for long-term use
Key counselling points include: take consistently (some statins are best taken at night), report muscle pain/weakness (risk of rhabdomyolysis), baseline and follow-up liver function tests, avoid excessive grapefruit juice (CYP3A4 interaction with some statins), and emphasise long-term adherence.
Question 5: What is the difference between a generic medicine and a branded medicine?
- A generic contains the same active ingredient, dose, and dosage form as the brand but is marketed under the non-proprietary (generic) name, usually at a lower cost (Correct answer)
- Generic medicines are less effective than branded medicines
- Generic medicines contain different active ingredients
- There is no difference — the terms are interchangeable
Correct answer: A generic contains the same active ingredient, dose, and dosage form as the brand but is marketed under the non-proprietary (generic) name, usually at a lower cost
Generic medicines must contain the same active ingredient in the same dose and dosage form as the reference (branded) product and must demonstrate bioequivalence. They are approved by the HPRA and meet the same quality standards but are typically less expensive as they do not carry development costs.
Question 6: What is antimicrobial stewardship and why is it important for pharmacists?
- A systematic approach to optimising antibiotic use by ensuring the right drug, dose, and duration to improve outcomes and reduce antimicrobial resistance (Correct answer)
- Keeping antibiotics in stock at all times
- Selling as many antibiotics as possible
- Only prescribing the newest antibiotics available
Correct answer: A systematic approach to optimising antibiotic use by ensuring the right drug, dose, and duration to improve outcomes and reduce antimicrobial resistance
Antimicrobial stewardship involves selecting the optimal antibiotic, dose, and duration of therapy to maximise clinical cure while minimising side effects and the development of antimicrobial resistance. Pharmacists play a key role in reviewing prescriptions, advising prescribers, and educating patients.
PSI Clinical Therapeutics
What is the mechanism of action of proton pump inhibitors (PPIs) such as omeprazole?