Pharmacology

Question 0

Prophylaxis for toxoplasma gondii? What CD4 count is a risk factor?

Answer 0

TMP-SMX

CD4 < 100

Question 1

MAC prophylaxis? When to administer? Presentation?

Answer 1

azithromycin
CD4 < 50

Nonspecific symptoms: fever, weight loss, diarrhea

Widespread involvement of the RES system can lead to anemia, hepatosplenomegaly, and elevated alkaline phosphatase and lactate dehydrogenase.

Question 2

Prophylaxis for Histoplasma capsulatum? What CD4 count is a risk factor?

Answer 2

itroconazole

CD4 < 150 (100 in FA)

Question 6

TB drug most effective against intracellular organisms? What pH required?

Answer 6

Pyrazinamide

acidic pH present in macrophage phagolysosomes needed for its antimicrobial effects

Question 7

1st line for long-term management for chronic asthma?

Answer 7

inhaled glucocorticoids like Fluticasone

(high-dose systemic glucocorticoids generally reserved for initial management of acute asthma exacerbations; inhaled glucocorticoids are used to prevent acute exacerbations and do NOT have a role in treatment of acute episodes)

Question 8

What TB drug would cause a loss of acid-fastness in addition to halting proliferation?

Answer 8

INH
inhibits synthesis of mycolic acid (component of cell wall)

mycolic acids are what stain red on acid-fast – INH causes loss of acid-fast stain

Question 9

What agent can be used to treat symptoms of pulmonary arterial hypertension in a pt with primary pulmonary hypertension (PPH) waiting for a lung transplant?

Answer 9

Bosentan
competitive antagonist at endothelin-1 receptors

endothelin-1 is a potent vasoconstrictor and stimulates endothelial proliferation (block decreases pulm. vascular resistance)

Question 10

Mechanism of INH? Mechanism of ethambutol?

Answer 10

INH prevents mycolic acid synthesis (component of cell wall)

Ethambutol prevents polymerization of the mycobacterial cell wall

Question 11

What is the mechanism of echinocandins (like caspofungin)?

Answer 11

inhibit synthesis of beta-glucan
(a polysaccharide and essential component of the fungal cell wall)

all end in “-fungin”

Question 12

What is the mechanism of flucytosine?

Answer 12

inhibits DNA and RNA biosynthesis

converted to 5-FU within the fungal cell

Question 13

Mechanism of Nystatin? Other drug in this class?

Answer 13

bind to ergosterol and form pores (leakage of ions and cell lysis)

Amphotericin B

Question 14

What is N-acetylcysteine used for? Mechanism?

Answer 14

• cystic fibrosis treatment (mucolytic)
• acetaminophen overdose

In CF, cleaves disulfide bonds within mucus glycoproteins to loosen thick sputum.