Pharmocology Flashcards
What are the non-selective Cyclooxygenase inhibitors? (7)
- aspirin*
- sodium salicylate
- indomethacin
- ibuprofen*
- naproxen*
- phenylbutazon
- diclofenac
aspirin
- non-selective COX inhibitor (NSAID)
- irreversibly inhibits via covalent binding (acetylation)
- effect: decreases synthesis of thromboxanes and PGs
indomethacin
Non-selective COX inhibitor (NSAIDs)
ibuprofen
Non-selective COX inhibitor (NSAIDs)
naproxen
Non-selective COX inhibitor (NSAIDs)
- trade name: Aleve
- long half-life (>6 hrs)
Distinguish acetaminophen from the mechanism of NSAIDs.
reversibly inhibits cyclooxygenase (mostly in CNS - inactivated peripherally)
- antipyretic and analgesic, not anti-inflammatory
- drug of choice for fever/headache in infants
celecoxib
AKA celebrex
- the only COX-2 specific inhibitor that’s still on the market
- used particularly for rheumatoid arthritis, osteoarthritis, and ulcers
methotrexate
- folic acid analog (dihydrofolate reductase inhibitor)
- anti-rheumatic
- immunosuppressant
- inhibits T and B cell proliferation (arrests cell growth in G1 phase)
leflunomide
- anti-rheumatic
- immunosuppressant
- blocks pyrimidine synthesis by inhibiting dihydroorate dehydrogenase (reduces T and B cell proliferation)
- given as pro-drug (must be metabolized into active form)
etanercept
- anti-rheumatic
- TNF-alpha blocker
- often combined w methotrexate
infliximab
- anti-rheumatic
- TNF-alpha blocker
- often combined w methotrexate
anakinra
- anti-rheumatic
- inhibits IL-1 (IL-1 Ra analogue)
What are the two fates of the arachidonic acid pathway, and what are each of their committed enzymes?
- Leukotrienes; formation is catalyzed by 5-lipoxygenase
2. Thromboxane A2, prostacyclin, prostaglandins (committed step catalyzed by cyclooxygenase 1 and 2)`
Generally, what are the targets of corticosteroids vs NSAIDs?
- corticosteroids inhibit phospholipase A2 (which catalyzes the formation of arachidonic acid from membrane phospholipids)
- NSAIDs inhibit cyclooxygenase 1 and 2 (which catalyze the formation of thromboxane A2, prostacyclin, and prostaglandins from arachidonic acid)
Contrast the functions of cyclooxygenase 1 and 2.
COX-1: protective/ maintenance function throughout the body; generates low PG levels
- gastric mucosa
- platelet aggregation
- uterine contraction
COX-2: expression has to be induced by inflammatory mediators; expressed in kidneys and brain; generates high PG levels;
- local inflammation
- wound healing
- resistance to infection
Generally, what is the purpose of both cyclooxygenases?
They convert arachidonic acid to various prostanoids in different tissues
Which NSAIDs have a short half-life vs a long one?
Short (6 hrs): naproxen, salicylate, phenylbutazone
Which NSAIDs are COX-2 specific, and what is the main toxicity concern? (2)
Celecoxib (Celebrex, only one still on the market)* and Rofecoxib (Vioxx)
- increased risk of thrombosis
- other COX2 inhibitors pulled for cardiovascular effects
What is the only drug that irreversibly inhibits cyclooxygenases?
aspirin
What are the toxicity concerns associated with NSAIDs? (3)
- interstitial nephritis
- gastric ulcer (PGs protect gastric mucosa)
- renal ischemia (PGs vasodilate afferent arteriole)
What interaction is problematic with acetominophen and why?
Mixture with ethanol causes increased production of NAPQI (hepatotoxin metabolite) via CYP2E1