Duan: Pharm Control of Pain and Inflammation Flashcards
What is the method of action of aspirin?
covalently and irreversibly modifies COX1 and COX2 by acetylating serine 5-30 and preventing arachidonic acid from binding
Which COX pathway does aspirin block? Why is this important?
Both COX 1 and COX2; causes both a clinical and an adverse effect
Aspirin can inhibit (blank) production, which suppresses platelet adhesion and aggregation. This is why aspirin is the most commonly used antiplatelet agent for both the management of acut ischemic stroke and for prevention of stroke.
thromboxane A2
In what types of patients is use of salicylates contraindicated in?
patients with bleeding disorders
Salicylates are not recommended in pregnant women. What two things can they cause?
postpartum hemorrhage
premature closure of the fetal ductus arteriosus
The effects of aspirin are (blank) dependent
dose-dependent
What effects does a low dose of aspirin have?
What effects does an intermediate dose have?
What effects does a high dose have?
blocks platelet aggregation;
antipyretic, analgesic;
anti-inflammatory
5 clinical uses of aspirin
- fever
- pain (mild-to-moderate)
- rheumatic fever
- inflammatory diseases (rheumatoid arthritis, pericarditis)
- lower doses can reduce the risk of death from a heart attack or risk of stroke
What’s considered a low dose of aspirin? What’s a high dose?
low is less than 300 mg/day
high is 2400-4000 mg/day
What type of acids are salicylates? What’s the pKa?
weak organic acids; pKa of 3.5
Salicylates are rapidly absorbed from the stomach as well as the intestine where the pH is (blank) and favors (blank)
low; absorption
At low and moderate doses of salicylate, what “order” elimination is occurring? At what total body salicylate concentration does elimination become zero order?!
1st order; >3.5g/day or 600mg
How would you get aspirin out in the urine after an overdose?
give a base to raise the urine pH above 8, so that clearance is increased by 4 fold
What is the plasma half-life of salicylate? The half-life is dose dependent, though.
If dose is 300-650, what is the half-life?
If dose is 1g, what is the half-life?
If dose is 2g, what is the half-life?
If high dose (>3.5g/day) or overdose, what is the half-life?
~15 minutes; 3.1 to 3.2 hours; 5 hours 9 hours 15 HOURS!!!
why is admin of aspirin dose-dependent?
enzymes for glycine and glucuronide conjugation become saturated, so drug cannot be effectively eliminated
What is the difference between first order and zero order elimination?
Zero order elimination: fixed elimination - the same amount is eliminated, regardless of dose.
First order: with more drug plasma, there is faster elimination.
3 phases of inflammation
- acute
- subacute or delayed
- chronic proliferative
What phase of inflammation is described:
vasodilation and capillary permeability
acute
What phase of inflammation is described:
infiltration of leukocytes and phagocytes
subacute/delayed
What phase of inflammation is described:
tissues regeneration and fibrosis
chronic proliferative
List 5 symptoms of inflammation
- redness
- heat
- pain
- swelling
- loss of function
Characterized by inflammatory changes and symptoms (pain, heat, redness, and swelling) and subsequent tissue damage with atrophy and rarefaction of the bones. In late stages, deformity and ankylosis develop.
arthritic disorders
Causes of arthritic disorders are complex and usually cannot be cured. What is the goal of treatment?
relieve inflammation control pain improve function prevent further joint damage improve quality of life
In the inflammatory cascade, what activates the adaptive or innate immune system? Both of these result in leukocyte and endothelial cell activation. What do these go on to activate? What does this lead to?
a perceived threat, infection, or tissue injury;
biochemical inflammatory mediators;
inflammation
Symptoms of inflammation are caused by a series of biochemical mediators. List a few.
vasoactive amines platelet activating factor complement kinin system cytokines NO adhesion molecules arachidonic acid metabolites
What are four arachidonic acid metabolites?
thromboxane A2
HETE
leukotrienes
prostaglandins
What do the products of the LOX pathway, (HETE, Leukotrienes, and Lipoxins) cause?
phagocyte mobilization
changes in vascular permeability
inflammation
What do the products of the COX pathway (prostaglandins, prostacyclin, and thromboxane) cause?
inflammation
Arachidonic acids are (blank) carbon fatty acid chains that produce (blank) and (blank). They are immune system (blank)
20; prostanoids; leukotrienes; modulators
Membrane phospholipids form arachidonic acid via what enzyme? There are two pathways, COX-1 and COX-2. Which is constitutive and under physiological regulation? Which is inducible, and results in an inflammatory response?
phospholipase A2
COX-1
COX-2
The COX1 reaction forms prostaglandins associated with what three things?
platelet function
GI mucosal integrity
renal function
The COX2 reaction forms prostaglandins associated with what three things?
inflammation
pain
fever
What do prostaglandins do to pain fibers?
directly sensitize them, causing them to respond to normally innocuous stimuli
What is it called when a normally innocuous stimulus becomes painful?
hyperalgesia
What does subdural injection of PGE1 with small amounts of bradykinin or histamine cause?
headache and pain
A common cause of fever is the production of (blank) released by neutrophils fighting a bacterial infection.
pyrogens
List three pyrogens
cytokine IL-1
IL-6
TNF-alpha
Pyrogens are thought to cause release of (blank) in the preoptic area of the hypothalamus. The net effect is an imbalance in heat production leading to (blank). Inhibition of (blank) synthesis in the CNS can cause cutaneous vasodilation and increased heat loss, thus can reduce the (blank). A general reduction of prostaglandin synthesis in the brain and in inflamed tissues probably also reduces the symptoms of fever.
prostaglandins; fever; prostaglandin; fever
What do 5-LOX inhibitors and leukotriene receptor antagonists do?
block the LOX pathway –> block formation of inflammatory mediators
What do NSAIDS do?
block the COX pathway –> block the formation of inflammatory mediators
What do corticosteroids (ex: prednisone) block?
phospholipase A2 –> can’t produce arachidonic acid from phospholipids
1950: Dr. Lawrence L. Craven of California describes his observations about aspirin’s action as a (blank), and begins prescribing daily doses to his patients as a means of preventing heart attacks
1971: British pharmacologist John R. Vane discovers aspirin’s mechanism of action — that it inhibits the production of hormone-like substances in the body called (blank).
1982: Sir John R. Vane is co-winner of the Nobel Prize in Medicine for his discoveries concerning prostaglandins.
blood-thinner; prostaglandins;
If you take antacids with aspirin, what will this cause?
reduced rate of aspirin absorption
If you take heparin or oral anticoagulants with aspirin, what will this cause?
hemorrhage
If you take probenecid or sulfinpyrazone with aspirin, what will this cause?
decreased urate excretion (not good for gout patients)
If you take bilirubin, phenytoin, naproxen, sulfinpyrazone, thiopental, thyroxine, or triiodothyronine with aspirin, what will this cause?
increased plasma concentration leading to prolonged half-lives, therapeutic effects, and toxicity
List some adverse effects of aspirin
GI symptoms allergic reaction CNS toxicity salicylate reaction renal damage hematologic effects metabolic acidosis
What three things can overdose of aspirin lead to?
Reye’s syndrome (kids)
severe hepatic damage
encephalopathy
What dose of aspirin causes salicylism (overdose or poisoning)? What are the symptoms? In children, what are some common signs of toxicity?
> 5g/d of aspirin
In adults, tinnitus, hearing loss, vertigo
Acidosis, hyperventilation, and lethargy in children
What can you due to “rescure” a pt that has overdosed on aspirin?
- NaHCO3 alkalinize urine with bicarb (A-)
- correct acid-base disturbance
- replace electrolytes and fluids
- cool
- forced diuresis, hemodialysis
- gastric lavage or emesis