Saudi Prometric Pharmacist Clinical Pharmacy and Therapeutics 3

Question 1

A patient with Parkinson's disease is on levodopa/carbidopa therapy. What is the purpose of carbidopa in this combination?

Accepted Answer

Peripheral DOPA decarboxylase inhibitor — prevents peripheral levodopa conversion, increasing CNS levodopa delivery and reducing side effects

Answer

Carbidopa inhibits peripheral aromatic L-amino acid decarboxylase (DOPA decarboxylase), preventing levodopa from being converted to dopamine in the bloodstream. This reduces peripheral dopamine side effects (nausea, hypotension) and allows more levodopa to enter the CNS, requiring lower doses.

Question 2

Which drug is first-line for treatment of Helicobacter pylori eradication failure after standard triple therapy?

Accepted Answer

Bismuth quadruple therapy (PPI + bismuth + metronidazole + tetracycline) for 10–14 days

Answer

When first-line clarithromycin-based triple therapy fails, bismuth quadruple therapy (PPI + bismuth subsalicylate + metronidazole + tetracycline) for 10–14 days is recommended as second-line. Fluoroquinolone-based triple therapy is an alternative but resistance is increasing.

Question 3

A pharmacist is counseling a patient starting allopurinol for chronic gout. When should allopurinol be initiated?

Accepted Answer

2–4 weeks after resolution of the acute attack, with co-prescription of colchicine or NSAID prophylaxis initially

Answer

Allopurinol should be started 2–4 weeks after the acute attack has resolved to avoid prolonging the current attack (rapid changes in urate can trigger inflammation). Initial prophylactic colchicine or NSAID (at low dose) is prescribed for 3–6 months to prevent flares triggered by urate lowering.

Question 4

A patient on phenytoin is started on oral contraceptives. What is the clinical concern?

Accepted Answer

Phenytoin induces CYP3A4, increasing OC metabolism and reducing contraceptive efficacy — use alternative contraception

Answer

Phenytoin (and carbamazepine, rifampin) induces CYP3A4 and other enzymes that metabolize ethinyl estradiol and progestins in oral contraceptives, reducing plasma levels by 50–80%. This can cause contraceptive failure. Patients need non-hormonal backup or higher-dose OC with agreement from prescribers.

Question 5

A patient with community-acquired pneumonia (CAP) of moderate severity is to be treated as an outpatient. What is the preferred antibiotic regimen?

Accepted Answer

Amoxicillin-clavulanate + macrolide (or respiratory fluoroquinolone alone)

Answer

Outpatient CAP treatment: for low-risk patients, amoxicillin alone or amoxicillin-clavulanate + a macrolide covers typical and atypical organisms. A respiratory fluoroquinolone (levofloxacin/moxifloxacin) alone is an alternative. The combination covers S. pneumoniae and atypical pathogens (Mycoplasma, Chlamydophila, Legionella).

Saudi Prometric Pharmacist Practice Test

Saudi Prometric Pharmacist Practice Test

Saudi Prometric Pharmacist Clinical Pharmacy and Therapeutics 3