Pharmacology

Question 1

What are the direct effects of circulating Levodopa and dopamine?

Answer 1

-Postural hypotension(from direct vascular effect)
-Nausea
-Arrhythmias

Question 2

What antibiotic is given to close contacts of a patient with meningococcal meningitis?

Answer 2

Ciprofloxacin
(Rifampicin, Azithromycin, or Ceftriaxone are potential alternatives)

Question 3

62 year old woman was admitted for nausea, vomiting, and yellow visual field discoloration after mistakenly taking 250mcg of digoxin for the last 2 weeks. What biochemical abnormality, if present, would exacerbate symptoms of digoxin toxicity?

Answer 3

Hypokalaemia.

Potassium depletion enhances binding of digoxin to Na/K+ pump.
Also hypomagnesaemia.

Question 4

You prescribe granisetron for a patient suffering from chemotherapy-induced nausea and vomiting. What is the primary site of action of granisetron?

Answer 4

Medulla oblongata
(5HT-3 receptor antagonist found in the area postrema of the medulla oblongata.
It is thought to have negligible activity at other 5HT or dopamine receptors)

Question 5

29 year old gamekeeper with at a national park presents with a single erythematous target-like lesion on his calf and you suspect erythema migrans. He has penicillin allergy. What is the most appropriate treatment?

Answer 5

Doxycycline for 14-21 days.(for Lyme disease)

Question 6

What is the most appropriate initial management of amiodarone-induced thyrotoxicosis in an unstable patient with positive thyroid auto antibodies diffuse uptake on thyroid isotope scan?

Answer 6

Propylthiouracil.

(Used for stable and unstable type-1 amiodarone-induced thyroiditis. Steroids used for type-2: no antibodies or uptake on isotope scan)

Question 7

Side effects of Theophylline

Answer 7

-Agitation
-Insomnia
-Headache
-Seizures
-Nausea and vomiting
-Peptic ulceration
-Hypokalaemia
-Metabolic acidosis

Toxicity=profound hypokalaemia, ventricular and supraventricular arrhythmias

Question 8

What is the mode of action of Ciprofloxacin?

Answer 8

Inhibition of DNA gyrase

Question 9

A young woman previously treated for pneumonia with antibiotics presents with fatigue, malaise, and elevated urea and creatinine. You suspect acute interstitial nephritis. What medication may have caused this?

Answer 9

Penicillin