MODULE6- ANTIINFLAMMATORY Flashcards
the cyclooxygenase (COX) pathway of arachidonate metabolism produces:
- PG pathway
- Leukotrienes pathway
” Dial 1 for Housekeeping”
Dial 2 for inflammatory
prostaglandins, which have a variety of effects on
- blood vessels,
- on nerve endings,
- and on cells involved in inflammation.
The______________- of arachidonate metabolism yields leukotrienes,
which have a powerful chemotactic effect on eosinophils,
neutrophils, and macrophages and promote bronchoconstriction
and alterations in vascular permeability.
** lipoxygenase pathway**
THERAPEUTIC STRATEGIES
The treatment of patients with inflammation involves two primary __goals:
- first, the relief of symptoms and the maintenance of
function, which are usually the major continuing complaints of the patient;
- and second, the slowing or arrest of the tissue-damaging
process.
In rheumatoid arthritis, response to therapy can be
quantitated using several measures such as the :
- Disease Activity
Scale (DAS),
- the Clinical Disease Activity Index (CDAI), and
- the American College of Rheumatology Response index (ACR
Response).
The first two are continuous variables denoting both
state and change,
Disease Activity
Scale (DAS),
the Clinical Disease Activity Index (CDAI),
is solely a change measure.
American College of Rheumatology Response index (ACR
Response).
THERAPEUTIC STRATEGIES
- nonsteroidal antiinflammatory
drugs (NSAIDs) - glucocorticoids
- diseasemodifying
antirheumatic drugs (DMARDs) - biologics (a
subset of the DMARDs).
- *Salicylates and other similar agent**s used to treat rheumatic disease
- *share the capacity to suppress the signs and symptoms** of inflammation.
These drugs also exert antipyretic and analgesic effects,
but it is their anti-inflammatory properties that make them most
useful in the management of disorders in which pain is related to
the intensity of the inflammatory process.
NONSTEROIDAL
ANTIINFLAMMATORY DRUGS
Note : Since aspirin, the original NSAID, has a number of adverse
effects, many other NSAIDs have been developed in attempts to
improve upon aspirin’s efficacy and decrease its toxicity.
Chemistry & Pharmacokinetics of NSAIDS
- grouped in several chemical classes
- chemical diversity yields a broad range of pharmacokinetic
characteristics - some general properties in common
- Most of these drugs are well absorbed, and food does not substantially change their bioavailability
- highly metabolized, some by phase I followed by phase II mechanisms
and others by direct glucuronidation (phase II) alone - While renal
excretion is the most important route for final elimination, nearly
all undergo varying degrees of biliary excretion and reabsorption
(enterohepatic circulation). - Most of the NSAIDs are highly protein-bound
(∼ 98%), usually to albumin.
*
All but one of the NSAIDs are weak
organic acidsas given; the exception, ______________, is aketone prodrug that is metabolized to theacidic active drug.
nabumetone
Most of the NSAIDs (eg, ibuprofen,
ketoprofen) areracemic mixtures, while one, ___________, is provided
as a single enantiomer
naproxen
and a few have no chiral center
_________________
(eg, diclofenac).
All NSAIDs can be found in______________after repeated dosing.
** synovial fluid**
Note : Drugs with short half-lives remain in the joints longer than would be predicted from their half-lives, while drugs with **longer **half-lives disappear from the synovial fluid at a rate proportionate
to their half-lives.
Pharmacodynamics
NSAID anti-inflammatory activity
NSAID anti-inflammatory activity is mediated chiefly through
_____________________
inhibition of prostaglandin biosynthesis
Various
NSAIDs have additional possible mechanisms of action, including
- inhibition of chemotaxis,
- down-regulation of interleukin-1 production,
- decreased production of free radicals and superoxide, and
- interference with calcium-mediated intracellular events.
The selective COX-2 inhibitors do not affect
platelet function at their usual doses
are somewhat more effective in inhibiting COX-1.
- aspirin,
- ibuprofen,
- indomethacin,
- piroxicam, and
- sulindac
The
efficacy of COX-2-selective drugs equals that of the older
NSAIDs,whileGI safety may be improved. On the other hand,
selective COX-2 inhibitors may increase the incidence of
edema and hypertension
As of August 2011, ____________ and _____ were the only COX-2 inhibitors marketed in the
USA.
celecoxib and the less selective
meloxicam
_________________, two previously marketed, selective
COX-2 inhibitors, were withdrawn from the market because
of their association with increased cardiovascular thrombotic
events.
Rofecoxib and valdecoxib
___________ has a Food and Drug Administration initiated
“black box” warning concerning cardiovascular risks. It has been
recommended that all NSAID product labels be revised to mention
cardiovascular risks.
Celecoxib
To varying
degrees, all newer NSAIDs are analgesic, anti-inflammatory, and
antipyretic, and all (_________________ and the
___________________) inhibit platelet aggregation.
except the COX-2-selective agents
** nonacetylated salicylate**s
NSAIDs are
all ______________ and can be associated with GI ulcers and bleeds
as well, although as a group the newer agents tend to cause less GI
irritation than aspirin.
gastric irritants
____________ has been observed for all of the drugs for which extensive experience has been reported.
Nephrotoxicity
Nephrotoxicity is due, in part, to_____________
of renal blood flow, which is modulated by prostaglandins.
Hepatotoxicity can also occur with any NSAID.
interference with the autoregulation
Although these drugs effectively inhibit inflammation, there is
no evidence that—in contrast to drugs such as methotrexate and
other DMARDs—they alter the course of any arthritic disorder.
They can inhibit the inflammation but cant alter the arthritic disorder. :)
Several NSAIDs (including aspirin) reduce the incidence of
____________ when taken chronically. Several large epidemiologic
studies have shown a 50% reduction in relative risk when the drugs
are taken for 5 years or longer. The mechanism for this protective
effect is unclear.
colon cancer
The NSAIDs have a number of commonalities. Although not all
NSAIDs are approved by the FDA for the whole range of rheumatic
diseases, most are probably effective in rheumatoid arthritis, seronegative
spondyloarthropathies (eg, psoriatic arthritis and arthritis associated with inflammatory bowel disease), osteoarthritis, localized
musculoskeletal syndromes (eg, sprains and strains, low
back pain), and gout (except ________, which appears to be ineffective
in gout).
tolmetin
Adverse effects are generally quite similar for all of the NSAIDs:
1. Central nervous system: Headaches, tinnitus, and dizziness.
2. Cardiovascular: Fluid retention, hypertension, edema, and rarely, myocardial infarction, and congestive heart failure.
3. Gastrointestinal: Abdominal pain, dysplasia, nausea, vomiting, and rarely, ulcers or bleeding.
4. Hematologic: Rare thrombocytopenia, neutropenia, or even aplastic anemia.
5. Hepatic: Abnormal liver function tests and rare liver failure. 6. Pulmonary: Asthma.
7. Skin: Rashes, all types, pruritus.
8. Renal: Renal insufficiency, renal failure, hyperkalemia, and proteinuria.
This long use and availability without prescription diminishes
its glamour compared with that of the newer NSAIDs. This is
now rarely used as an anti-inflammatory medication and will be
reviewed only in terms of its anti-platelet effects (ie, doses of
81–325 mg once daily).
ASPIRIN
The
salicylates are rapidly absorbed from the stomach and upper small intestine yielding a peak plasma salicylate level within____________
1–2 hours.
Aspirin is absorbed as such and is rapidly hydrolyzed (serum halflife
___________) to acetic acid and salicylate by esterases in tissue
and blood ( Figure 36–3 ).
Salicylate is nonlinearly bound to albumin.
Alkalinization of the urine increases the rate of excretion of
free salicylate and its water-soluble conjugates.
15 minutes
Mechanisms of ActionAspirin
_________________
In other
tissues, synthesis of new COX replaces the inactivated enzyme so
that ordinary doses have a duration of action of 6–12 hours.
irreversibly inhibits platelet COX so that aspirin’s antiplatelet
effect lasts 8–10 days (the life of the platelet).
Aspirin decreases the incidence of transient ischemic attacks,
unstable angina, coronary artery thrombosis with myocardial
infarction, and thrombosis after coronary artery bypass grafting
(see Chapter 34 ).
Epidemiologic studies suggest that long-term use of aspirin at
low dosage is associated with a lower incidence of colon cancer,
possibly related to its COX-inhibiting effects.
colon cancer decrease incidence
Adverse Effects
In addition to the common side effects listed above, aspirin’s
main adverse effectsatantithrombotic doses are______________.
_____________ rarely if ever occur
at antithrombotic doses.
- gastric upset (intolerance) and
- gastric and duodenal ulcers
- Hepatotoxicity, asthma, rashes, GI bleeding, and renal toxicity
The antiplatelet action of aspirin contraindicates its use by
patients with __________
hemophilia
. Although previously not recommended
during pregnancy, aspirin may be valuable in treating ______________
preeclampsiaeclampsia.