AC Test Wk 1-5 (All Answered Correctly)

sulfonamide inhibits correct answers dihydropteroate synthase cos it is PABA (p-aminobenzoic acid) analogue Trimethoprim inhibits ____ whats special bout the enzyme? correct answers dihydrofolate reductase --in both human and bacteria but trimethoprim is more sensitive to bacteria one (needs high concentration of drug to inhibit human one) 3 types of functions of selective toxicity correct answers diff in distribution--accummulate more in bacterial cell (tetracycline- bact cell has pump, griseofulvin stays in keratinised cells) diff in comparative biochemistry-diff in synthesis, analogous enzymes (diff affinity to drug) diff in comparative cytology-Ab moa, chem structure, bactericidal/bacteristatic, spectrum Which 2 Pc are natural? Describe correct answers PcG and PcV easily deactivated by beta-lactamase Pc structure correct answers thiazolidine ring, beta-lactam ring, side chain When adminster IV or IM Pc, what reaction can expect correct answers Jarisch-Herxheimer reaction (fever, chill, headache) Which Pc contains Na which may lead to HF? correct answers PcG (BenzylPc) Which 2 Pc have rapid onset and which 2 have slow onset? Why are they slower? correct answers Quick: PcG and PhenoxymethylPc Slow: Procaine BenzylPc and Benzathine BenzylPc Slow cos need to hydrolyse to PcG Compare Procaine benzylPc and Benzathine BenzylPc correct answers Both are IM Peak for Pro is 1-4hrs; Benza is 24 hrs Dose for Pro is 1 d; Benza is every 2 wks Both have low plasma conc so bacteria must be very sensitive to drug Name the spectrum for the following: PcG Procaine benzathine phenoxymethylPc correct answers Narrow cos Pc MOA of Pc