Learn / FMK
Every FMK condition
299 diseases, deficiencies, toxicities and drug mechanisms harvested from every FMK deck — the ones sprinkled through a single bullet as much as the ones with their own slide. Pick what you're given and what you have to name, or let it cycle; distractors come from the same category so you have to discriminate (hypoketotic vs. ketotic hypoglycemia, which GSD, which urea-cycle enzyme…). Every answer shows the whole card with the lecture and slide.
Toxin/Drug · FMK 08.1
Hydroxyurea Acquired / not inherited
Defect / target: Directly inhibits ribonucleotide reductase (RNR)
Mechanism: Blocks conversion of all ribonucleoside diphosphates to deoxyribonucleoside diphosphates, halting dNTP production and therefore DNA synthesis in rapidly dividing cells.
↑ Accumulates: Ribonucleotides (NDPs)· ↓ Deficient: All four dNTPs
Presentation: Used as an antineoplastic (melanoma, myeloproliferative disorders) and at lower doses in sickle cell disease to raise fetal hemoglobin; toxicity is myelosuppression
RNR is the ONLY enzyme making deoxyribonucleotides — inhibited by hydroxyurea pharmacologically, by dATP pathologically (ADA deficiency)
Learn the mechanism: Purine synthesis & salvage →
FMK 08.1 Nucleic Acid Metabolism · slide 15, 29