Nonsteroidal anti-
inflammatory drugs (NSAID)
Ali Jaber, Ph.D.
MS in Pharmacy
MS in Pharmaceutical Chemistry
The inflammatory response
occurs in vascularised tissues in
response to injury.
It is part of the innate nonspecific immune
response.
Inflammatory responses require activation of
leukocytes: neutrophils, eosinophils,
basophils,mast cells, monocytes, and
lymphocytes,
(+)
Phospholipase A2 Phospholipids
Arachidonic acid
5-lipoxygenase
Leucotrienes
Cyclooxy genase (COX)
Endoperoxides
PGs TxA2
15-lipoxygenase
Lipoxins
Inflammatory stimulus
Ex
In
PGI2 (prostacyclin) is located
predominantly in vascular
endothelium. Main effects:
•vasodilatation
•inhibition of platelet aggregation
TxA2 is found in the platelets.
Main effects:
•platelet aggregation
•vasoconstriction
PROSTANOIDS (PGs & Txs)
PGE2 causes:
• inhibition of gastric acid secretion
•contraction of pregnant uterus
•contraction of GI smooth muscles
PGF2α – main effects:
•contraction of bronchi
•contraction of miometrium
Cyclooxygenase (COX) is found
bound to the endoplasmatic
reticulum. It exists in 3 isoforms:
• COX-1 (constitutive) acts
in physiological conditions.
• COX-2 (inducible) is
induced in inflammatory cells
by pathological stimulus.
• COX-3 (in brain).
Essential of Medical Pharmacology – 5st Ed. (2003)
COX-2
inhibitors • Selective (coxibs)
• Preferential
COX-3
inhibitors •Antipyretic
analgesics
Nonselective
COX-1/COX-2
inhibitors NSAIDs
COX inhibitors
Nonselective
COX-1/COX-2
inhibitors
(Classical NSAIDs) •Salicylates
•Phenylacetates
•Indolacetates
•Enolates
•Fenamates
•Propionates
•Butylpyrazolidindiones
•Pyrazolones
De rivatives
of acid
Acetylsalicylic acid (Aspirin®)
Paracetamol (Panadol)
Diclofenac (Voltaren)
Indometacin
Piroxicam (Brexin)
Meloxicam (Mobic)
Ibuprofen (Brufen)
Ketoprofen (Profenid)
Nonselective COX-1/COX-2 inhibitors
Beneficial actions of NSAIDs due
to prostanoid synthesis inhibition
1. Analgesia
prevention of pain nerve ending sensitization
2. Antipyresis
connected with influence of thermoregulatory
centre in the hypothalamus
3. Antiinflammatory action
mainly antiexudative effect
4. Antithrombotic action
in very low daily doses
5. Closure of ductus arteriosus
Shared toxicities of NSAIDs due
to prostanoid synthesis inhibition
1. Gastric mucosal damage
connected with PGE inhibition
2. Bleeding: inhibition of platelet
function (TxA2 synthesis)
3. Limitation of renal blood flow
Na+ and water retention
4. Delay / prolongation of labour
connected with PGF2α inhibition
5. Asthma and anaphylactoid reactions
connected with PGF2α inhibition
Lüllmann, Color Atlas of Pharmacology – 2nd Ed. (2000)
Aspirin® (Bayer, 1899) As analgesic for headache,pulled muscle, neuralgias.
As antipyretic in fever of any origin.
However, paracetamol is preferred
Acute rheumatic fever. Aspirin is the first drug of
choice. Other drugs substitute Aspirin only when it
fails or in severe cases.
Rheumatoid arthritis. Aspirin a dose of 3 to 5 g/24 h
after meal is effective in most cases. Since large
doses of Aspirin are poorly tolerated for a long time, the
new NSAIDs (diclofenac, ibuprofen, etc.) in depot
form are preferred.
Aspirin therapy in children with rheumatoid arthritis
has been found to raise serum concentration trans-
aminases, indicating liver damage. Most cases are
asymptomatic but it is potentially dangerous.
An association between salicylate therapy and
“Reye’s syndrome”, a rare form of hepatic
encephalopathy seen in children, having viral infection
(varicella, influenza), has been noted.
Aspirin should not be given to children under 15
years unless specifically indicated, e.g. for juvenile
arthritis (paracetamol is preferred).
Postmyocardial infarction and poststroke patients.
By inhibiting platelet aggregation in low doses (100 mg
daily) Aspirin decreases the incidence of reinfarction.
Arachidonic acid
Cyclooxygenase (COX)
Endoperoxides
PGs TxA2
(-)
Aspirin
Thromboxane A2 synthase
(-) 100 mg/24 h
>1 g/24 h
Drugs Result
Diuretics Decrease diuresis
Beta-blockers Decrease antihypertensive effect
ACE inhibitors Decrease antihypertensive effect
Anticoagulants Increase of GI bleeding
Sulfonylurea Increase hypoglycemic risk
Cyclosporine Increase nephrotoxicity
GCS Increase of GI bleeding
Alcohol Increase of GI bleeding
Drug interactions with NSAIDs
Ibuprofen (Brufen) Oral ibuprofen is often prescribed in lower doses at
which it has analgesic but not antiinflammatory
efficacy.
A topical cream preparation is absorbed into fascia
and muscle.
A liquid gel preparation of ibuprofen provides
prompt relief in postsurgical dental pain.
Ketoprofen (Profenid)
The effectiveness of ketoprofen at dosages of
100–300 mg/d is equivalent to that of other NSAIDs
in the treatment of rheumatoid arthritis, osteoarthritis,
gout, dysmenorrhea, and other painful conditions.
In spite of its dual effect on prostaglandins and
leukotrienes, ketoprofen is not superior to other
NSAIDs. Its major adverse effects are on the GIT
and the CNS.
Indometacin
Is a potent nonselective COX inhibitor and may also
inhibit phospholipase, reduce neutrophil migration,
and decrease T cell and B cell proliferation.
Indications:
juvenile rheumatoid arthritis, gout and post episiotomy
pain.
Side effects: A high incidence (up to 50%)
of GI and CNS side effects is produced: GI bleeding,
diarrhoea, frontal headache, mental confusion, etc.
Diclofenac (Voltaren)
Diclofenac in rectal suppository form can be
considered a drug of choice for
analgesia and postoperative nausea.
It is also available for intramuscular and oral
administration
Indications: All moderate pain
Side effects occur in approximately 20%: GI distress
and occult bleeding, gastric ulceration. A preparation
combining diclofenac and misoprostol (PGE1)
decrea-
ses upper GI ulceration but may result in diarrhoea.
Piroxicam, (Feldene) Its long half-life permits once-daily dosing.
Piroxicam can be used for the usual rheumatic
indications.
Side effects: Toxicity includes GI symptoms (20%
of patients), dizziness, tinnitus, headache, rash.
When piroxicam is used in dosages higher than
20 mg/d, an increased incidence of peptic ulcer
and bleeding is encountered. This risk is as much as
10 times higher with piroxicam than with other NSAIDs.
COX-2
inhibitors
(1) Selective COX-2
inhibitors (Coxibs)
• Celecoxib (celebrex)
• Etoricoxib (Arcoxia)
(2) Preferential
COX-2 inhibitors
• Meloxicam(Mobic)
• Nimesulide(Aulin)
Inhibiting activity rate
(COX-2/COX-1)
•Aspirin
•Indometacin
•Meloxicam
155
60
0,8
(Preferential COX-2 inhibitor)
Classical
NSAIDs
Coxibs are selective COX-2 inhibitors. They exert
antiinflammatory, analgesic, and antipyretic action
with low ulcerogenic potential. Coxibs can cause
infertility. They have prothrombotic cardiovascular
risk. The ulcerogenic potential of preferential
COX-2 inhibitors Meloxicam (Mobic), and
Nimesulide (Aulin®) is significant.
Celecoxib (Celebrex)is as effective as other
NSAIDs in the
treatment of rheumatoid arthritis and
osteoarthritis,
Side effects: celecoxib may cause rashes.
It does not affect platelet aggregation at usual
doses.
Etoricoxib (Arcoxia)
is a second-generation COX-2-selective inhibitor
Indications: treatment of the symptoms of
osteoarthritis, rheumatoid arthritis
and for the relief of acute musculoskeletal pain
Etoricoxib has similar efficacy to traditional NSAIDs
for osteoarthritis, acute gouty arthritis, and primary
dysmenorrhea and has a GI safety profile similar to
other coxibs.
Meloxicam (Mobic)
It has been shown to preferentially inhibit COX-2
over COX-1
It is not as selective as the other coxibs and may
be considered “
preferentially" selective rather than
“highly” selective.
Indications: treatment of osteoarthritis and
rheumatoid arthritis.
Side effects: are similar to those of other NSAIDs.
Comparative action between
COX inhibitors
COX-1/COX-2
inhibitors
COX-2
inhibitors
1. Analgesic action (+) (+) (+)
2. Antipyretic action (+) (+)
3. Antiinflammatory action (+) (+) (+)
4. Antiplatelet aggregatory (+) (-)
5. Gastric mucosal damage (+) (+) (+) (+)
6. Renal salt / water retention (+) (+)
7. Delay/prolongation of labor
8. Infertility
(+) (+)
(-)
(+)
(+) (+)
9. Ductus arteriosus closure (+) ?
10. Aspirin-like asthma
11. Cardiotoxicity
(+)
(-)
?
(+) (+)
Many severe side effects •Infertility (> PGF2α)
•Thrombosis (< PGI2; > TxA2)
Bextra® (Valdecoxib): Pfizer (penalty!)
COX-3
inhibitors
(antipyretic
analgesics)
NSAIDs in
low doses
NONOPIOID ANALGESICS
(1) Anilides
Paracetamol – tabl. 500 mg
(Acetaminophen – USAN)
Propacetamol (prodrug)
(2) Pyrazolones
Metamizole
(Analgin® – tabl. 500 mg)
(3) COX-1/COX-2 inhibitors
Aspirin®, Diclofenac,
Ibuprofen, Naproxen etc.
(4) COX-2 inhibitors
Pathogenesis
of pain
Lüllmann, Color Atlas of Pharmacology – 2nd Ed. (2000)
Acetaminophen (USAN)
(Paracetamol – INN)
•Efferalgan®
•Panadol®
•ParacetaMAX®
Propacetamol is a prodrug.
It converts into paracetamol.
Acetylsalicylic acid
•Aspirin®
•Aspegic® lisinate
(Metamizole – INN)
•Analgin®
•Proalgin®
Lüllmann, Color Atlas of Pharmacology – 2nd Ed. (2000)
Paracetamol (Panadol, Efferelgan)
paracetamol lacks antiinflammatory properties.
Indications: mild to moderate pain: headache,
myalgia,postpartum pain.
paracetamol is the preferred drug in children as
antipyretic and analgesic
Side effects: hepatotoxcity most of all
Acute paracetamol poisoning occurs especially in
small children who have low hepatic glucuronide conjugating
ability. If a large dose (> 150 mg/kg or > 10 g in adult)
is taken, serious toxicity can occur. The letal dose is 250 mg/kg