Q- Which of the following sympathomimetic drugs is the most effective in treating chronic orthostatic hypotension?
A- Ephedrine
B- Epinephrine
C- Norepinephrine
D- Salmeterol
A- Ephedrine works by stimulating both alpha and beta receptors and increasing norepinephrine release, which helps raise blood pressure steadily. Epinephrine and norepinephrine are used for acute cases like shock, but not for chronic cases. Salmeterol is a long-acting beta-2 agonist, used for asthma, not hypotension.
Q- Which of the following is the mechanism of action of methotrexate?
A- Alkylates DNA
B- Blocks topoisomerase II
C- Inhibits dihydrofolate reductase
D- Inhibits thymidylate synthase
C- Methotrexate competitively inhibits dihydrofolate reductase, blocking DNA synthesis in rapidly dividing cells.
Q- Which of the following medications acts by inhibiting bacterial cell wall synthesis?
A- Ceftriaxone
B- Ciprofloxacin
C- Doxycycline
D- Gentamicin
A- Ceftriaxone is a third-generation cephalosporine that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins.
