MSS drugs Flashcards
Acetaminophen
REVERSIBLE COX inhibitor; CNS action;
inactivated peripherally
Use: Antipyretic, analgesic but not inflammatory
Used in place of Aspirin to prevent Reye syndrome in children with viral infection
Tox: Hepatic necrosis.
metabolite (NAPQI) depletes glutathione and forms toxic tissue byproducts in liver
Antidote for acetaminophen tox: N-Acetylcysteine - regenerates glutathione
Aspirin
IRREVERSIBLE inhibition of COX (1 and 2) by acetylation
-> decreased synthesis of TXA2(increases platelet aggregation and vasoconstricts) and PGs
Increased bleeding time; No effect on PT, PTT
Type of NSAID
Use: low dose: decrease platelet aggregation
intermediate dose: antipyretic and analgesic
High dose: anti-inflammatory
Aspirin toxicity
Gastric ulceration, tinnitis (CNVIII)
Chronic: Acute Renal failure, interstitial nephritis, GI bleeding
Risk of Reye in children with viral infection
Causes Resp alkalosis early but transitions to metabolic acidosis - respiratory alkalosis
Celecoxib
Reversible COX2 inhibitor
COX2 found in inflammatory cells and vascular endothelium and mediates inflammation and pain
Spares COX-1 -> helps maintain gastric mucosa
Spares platelet function; TXA2 produced by COX1
Use: RA, OA
Tox: increased risk of thrombosis; sulfa allergy
NSAIDs
Ibuprofen, Ketolorac, Indomethacin, naproxen, diclofenac
REVERSIBLY inhibits COX1 and 2
Blocks PG synthesis
Antipyretic, analgesic, anti-inflammatory
Indomethacin - closes PDA
PG functions
PGE1 - decrease vascular tone
PGE2 and F2 - increases uterine tone
PGI2 (prostacyclin) - inhibits platelet aggregation, vasodilation
NSAID toxicity
Interstitial nephritis, gastric ulcer (PGE1 protects gastric mucosa by stimulating bicarb secretion), renal ischemia (PGs vasodilate afferent arteriole)
AT2 and PG effect on renal arterioles
AT2 constricts efferent arteriole -> increases GFR
PGs dilates afferent arteriole
Bisphosphonates
Alendronate, dronates - Pyrophosphate analog
Inhibit osteoclast activity by binding hydroxyapatite in bone
Use: Osteoporosis, Hypercalcemia, Paget’s disease
Teriparatide
Recombinant PTH analog (SubQ) -> increases osteoblast activity
Use: Osteoporosis (causes more bone growth than antiresorptive meds - bisphosphonates)
Tox: Transient hypercalcemia; increase risk for osteosarcoma
Uric acid prodcution
Nucleic acid/ Diet -> purines -> Hypoxanthine -> Xanthine via XO;
Xanthine -> plasma Uric acid via XO
Allopurinol
Inhibits Xanthine Oxidase -> decreased conversion of Hypoxanthine or xanthine to Uric acid
Use: lymphoma/leukemia -> prevent tumor lysis urate nephropathy
SE: increases concentration of 6MP and azathioprine (both metabolized by XO)
Febuxostat
Inhibit XO
Pegloticase
Uricase -> metabolizes Uric acid to allantoin (more water soluble product than uric acid)
Probenicid
Inhibits Uric acid and salicyclate (penicillin) reabsorption in PCT
Can precipitate uric acid calculi
