18. NSAIDs Flashcards
the overall role of NSAIDs is what?
combined anti-inflammatory, analgesic, and antipyretic properties - not curative but suppress the signs and sxs of inflammation (same manner as steroids, but are not steroids)
eicosanoids?
large family of compounds derived from lipid membranes
-arachidonic acid (AA) = dominant precursor (20-carbon fatty acid)
NSAIDS are structurally divergent weak organic acids that inhibit what?
prostaglandin (PG) and leukotriene (LT) synthesis
what are the predominant anti-inflammatory drug categories?
salicylates, propionic and acetic acid derivatives, oxicams, and COX-2 inhibitors
aspirin does what to the serine-520 of COX to inhibit its activity and exclude arachidonate from its active site?
uniquely and irreversibly acetylates
thromboxane (TXA2), prostacyclin (PGI2), and the prostaglandins (PGD2, PGE2, and PGF2a) are all what?
prostanoids
the prostanoids are synthesized from _____ and bind to receptors on _____. (hint: one word fills both blanks)
membranes
which COX is present in most tissues as the housekeeper enzyme? Which COX is inducible by inflammation and is not present at baseline (except in the brain)?
COX-1; COX-2
which has higher affinity to convert arachidonic acid to prostaglandin, COX-1 or COX-2?
both are the same
why is the excessive inhibition of COX-1 undesirable? What about COX-2 inhibition?
COX-1 maintains normal gastric mucosa and influences kidney function and platelet aggregation - so excessive inhibition is undesirable
inhibiiton of COX-2 is desirable
explain the COX-2 to COX-1 ratio?
mechanism to assess the balance of inhibition of the inducible COX-2….lower the ratio, the lower the COX-1 inhibition and the lower the overall side effect profile
each prostanoid is synthesized from what? (hint: looking for the intermediate, not arachidonic acid)
PGH2 - the short lived intermediate
the terminal synthetic enzymes that determine which prostanoid is produced is specific to what?
the cell
which prostanoid has multiple receptors?
PGE2 (has EP1-EP4)
COX-1 and COX-2 are also called what?
prostaglandin-H synthase 1&2
what reaction do COX-1/COX-2 facilitate?
Arachidonic acid to PGH2
which COX is the constitutive enzyme (but induced in the brain) and the only form of COX in platelets/
COX-1
which COX is the inducible enzyme (but constitutive in the brain)? It is upregulated by cytokines, and shear stress, GFs, and own products (Feed forward).
COX-2
peripheral _____ can gain access to the CNS and stimulate more PGE2.
PGE2
productino of PGE2 is tightly related to the upregulation of what?
COX-2
OTC NSAIDS are used acutely for what? chronically?
acute:
- fever
- sprains, strains, and lower back pains
- headaches
- dysmenorria
chronic:
- cardiovascular protection
Rx NSAIDs are used acutely for what? chronically?
acute:
- injury
- migraine
- surgery
- patent ductus arteriosis
- premature labor
chronic:
- RA
- osteoarthritis
- AS
adverse effects of NSAIDs on blood? COX enzyme effected? PG affected?
- prolonged bleeding time, GI blood loss
- COX-1
- inhibition of TXA2 synthesis
adverse effects of NSAIDs on GI? COX enzyme effected? PG affected?
- erosive gastritis; peptic ulceration exacerbation
- COX-1
- inhibition of PGI leading to decrease in gastric mucosal secretion
adverse effects of NSAIDs on pulmonary? COX enzyme effected? PG affected?
- bronchospasm, urticaria, rhinitis, nasal polyposis
- ?
- inhibition of COX allows lipoxygenase path to dominate
adverse effects of NSAIDs on renal? COX enzyme effected? PG affected?
- fluid retention, NA excretion azotemia, hyperkalemia, oliguria, anuria
- COX-1/COX-2
- inhibition of PG involved in regulation of renal blood flow, glomerular filtration, and renal Na and water excretion, mediates renin release