PSI Clinical Pharmacy & OTC 2 — Questions and Answers
Question 1: Which medication used for OTC heartburn works by neutralising gastric acid?
- Aluminium/magnesium hydroxide antacids (Correct answer)
- Omeprazole
- Ranitidine
- Domperidone
Correct answer: Aluminium/magnesium hydroxide antacids
Antacids (aluminium and magnesium salts, calcium carbonate) act quickly to neutralise existing stomach acid, providing rapid but short-lived relief. They do not reduce acid production.
Question 2: Emergency hormonal contraception (morning-after pill) available OTC in Ireland works primarily by:
- Delaying or preventing ovulation (Correct answer)
- Preventing fertilisation of an egg already ovulated
- Acting as an abortifacient
- Preventing implantation primarily
Correct answer: Delaying or preventing ovulation
Levonorgestrel (e.g., Levonelle, NorLevo) primarily prevents or delays ovulation when taken before the LH surge. It is most effective within 72 hours. It does not terminate an established pregnancy.
Question 3: Which OTC product is recommended for treating head lice in children?
- Dimeticone 4% lotion (physical insecticide) applied for 8 hours (Correct answer)
- Permethrin 1% cream rinse only
- Lindane shampoo
- Oral ivermectin OTC
Correct answer: Dimeticone 4% lotion (physical insecticide) applied for 8 hours
Dimeticone is a physical agent that coats and suffocates lice — resistance does not develop. It is preferred first-line in Ireland and the UK. Two applications 7 days apart are needed to kill newly hatched lice.
Question 4: A patient requests an OTC decongestant (xylometazoline nasal spray). What is the maximum recommended duration of use?
- 5–7 days (Correct answer)
- 28 days
- No limit
- 3 months
Correct answer: 5–7 days
Nasal decongestant sprays (alpha-agonists: xylometazoline, oxymetazoline) should not be used for more than 5–7 days to avoid rhinitis medicamentosa (rebound congestion from nasal blood vessel supersensitisation).
Question 5: Which OTC laxative class acts by softening stools and lubricating the bowel — suitable for patients who should not strain?
- Osmotic laxatives (lactulose/macrogol) (Correct answer)
- Stimulant laxatives (senna)
- Bulk-forming agents (ispaghula)
- Glycerol suppositories only
Correct answer: Osmotic laxatives (lactulose/macrogol)
Osmotic laxatives draw water into the bowel, softening stool. They are suitable post-surgery, post-MI or post-haemorrhoidectomy when straining must be avoided. Stimulants cause cramping.
Question 6: Which OTC topical preparation is used to treat cold sores (herpes labialis) and should be applied at the first sign of tingling?
- Aciclovir 5% cream (Correct answer)
- Fusidic acid cream
- Hydrocortisone 1% cream
- Zinc oxide cream
Correct answer: Aciclovir 5% cream
Topical aciclovir 5% cream inhibits herpes simplex virus DNA polymerase. Application at the prodromal tingling/itching stage (before vesicles form) is most effective in limiting lesion size and duration.
PSI Clinical Pharmacy & OTC 2
Which medication used for OTC heartburn works by neutralising gastric acid?