Wednesday 2 September 2015
Saturday 27 December 2014
Pharmacology of Non-Steroidal Anti-Inflammatory Drugs NSAIDs
Introduction:-
Non-steroidal
anti-inflammatory drugs (NSAIDs) have analgesic, anti-pyretic,
anti-inflammatory (in higher doses) and anti-platelet effects. The NSAIDs are
one of the most frequently prescribed groups of drugs, and include a variety of
drugs.
Analgesic effect:-
Anti-Pyretic effect:-
Antipyretics cause the hypothalamus to
override an interleukin-induced increase in temperature. The body then works to
lower the temperature, resulting in a reduction in fever.The most common antipyretics in the United
States are ibuprofen and aspirin, which are used primarily as pain relievers
Anti-Inflammatory
effect:-
Anti-Platelet effect:-
Usually
all NSAIDs are not referred for anti-platelet effect, however, Aspirin in low
doses produces anti-platelet effect by preventing the synthesis of Thromboxane A2.
Mechanism of Action:-
By blocking prostaglandins, undesirable
effects such as pain and inflammation are relieved. NSAIDs act on the
hypothalamus to inhibit prostaglandin E2 to produce an
anti-pyretic effect.Aspirin has
anti-platelet effect for the life span of platelets, because it binds
irreversibly with cyclooxygenase and permanently block thromboxane A2 rather
than other drugs of this class.
Classification:-
|
Drug Classifications
|
Prototype Drug
|
Related Drugs
|
|
Salicylates
|
Acetylsalicylic acid (aspirin, ASA, several drug names)
|
Choline magnesium
Choline salicylate
Balsalazide
Diflunisal
Mesalamine
Magnesium salicylate
Olsalazine
Salsalate
Sodium Salicylate
Sodium thiosalicylate
|
|
Propionic acids
|
Ibuprofen (Motrin, Advil, others)
|
Fenoprofen
Flurbiprofen
Ketoprofen
Naproxen
Oxaprozin
|
|
Acetic acids
|
Indomethacin (Indocin)
|
Diclofenac Potassium
Diclofenac Sodium
Etodolac
Ketorolac
Sulindac
Tolmetin
|
|
Enolic acids
|
There is no prototype for this classification.
|
Piroxicam
Meloxicam
Lornoxicam
Tenoxicam
|
|
Cyclooxygenase-2 enzyme
inhibitors(COX-2 inhibitors)
|
Celecoxib
|
Etoricoxib
Paracoxib
|
|
Fenamic acids
|
There is no prototype for this classification.
|
Diflunisal
Meclofenamate
Mefenamic acid
|
|
Anilides
|
Paracetamol
|
There are no related drugs at this time.
|
|
Non-acidic NSAIDs
|
There is no prototype for this classification.
|
Nabumetone
|
|
Butylpyrazolidines
|
Phenylbutazone
|
There are no related drugs at this time.
|
|
Pyrazolones
|
Metamizol
|
There are no related drugs at this time.
|
Uses:-
Common acute (short-term) conditions that can be treated
with NSAIDs include:
qHeadaches
qPainful periods
qToothache
qSoft tissue injuries such as sprains and strains
qInfections, such as the common cold or the flu (NSAIDs
do not treat the underlying infections, but can help to relieve
symptoms; especially fever
Common chronic (long-term) conditions that can be treated
with NSAIDs include:
qMost types of arthritis, including rheumatoid
arthritis and osteoarthritis
qBack pain
qNeck pain
Side Effects and Adverse Effects:-
Some of the
common side effects are:
qNausea
qVomiting
qRash
qDiarrhea
qLiver and
kidney failure
qEdema
qReye’s
Syndrome in children
qStomach
and intestinal adverse effects
qMay increase the risk
of heart attack and stroke in elderly patients
Interactions:-
qNSAIDs
reduce blood flow to the kidneys and therefore reduce the action of diuretics.
qIt cause
severe bleeding when taking with drugs that cause bleeding.
q NSAIDs
antagonize the action of drugs that are used to treat hypertension.
qNSAIDs
increase the negative effect of cyclosporine on kidney function.
qNSAIDs cause
stomach ulcers in patients taking alcoholic beverages.
Contraindications:-
NSAIDs should usually be avoided by people with the following conditions:
qPeptic ulcer
qA past transient ischemic attack
qCoronary
artery disease
qUncontrolled
hypertension
qA past stroke
qUndergoing Coronary artery bypass surgery
qKidney disease
qA past Myocardial infarction
qTaking aspirin for heart
qIn third trimester of pregnancy
Examples:Indomethacin
(Indocin)
qIndomethacin works
by reducing the production of prostaglandins.
qTreat patent ductus arteriosus (PDA) in
certain premature infants.
qSide effects are headache, dizziness,
vomiting, diarrhea, constipation etc.
qSome products that may interact: aliskiren,
ACE Inhibitors, angiotensin II receptor blockers, cidofovir, corticosteroids,
cyclosporine, lithium, methotrexate, pemetrexed, water pills.
qShould
not be prescribed to patients with any type of allergy.
Diclofenac sodium (Volteran):-
qDiclofenac is used to relieve pain, swelling,
and joint stiffness caused by arthritis.
qIts
side effects include upset stomach, nausea, diarrhea, constipation etc.
qDrug interactions are same as that of all
NSAIDs.
qPrecautionary measures should be as prescribed
by the doctor.
Piroxicam (Feldene):-
qThis medication is used in the treatment
of osteoarthritis; temporo mandibular joint disorder;
pain; frozen shoulder; rheumatoid arthritis.
qIts side effects are hives, difficulty
breathing; swelling of body parts, chest pain, shortness of breath,
slurred speech, problems with vision.
qDrug interactions are same as that of all
NSAIDs.
qPrecautionary measures should be as
prescribed by the doctor.
Meloxicam (Mobic) :-
qIt
is used in the treatment of osteoarthritis, rheumatoid arthritis, juvenile
rheumatoid arthritis,tendonitis.
qStomach upset, nausea, dizziness, or
diarrhea may occur.
qDrug interactions are same as that of all
NSAIDs.
qPrecautionary measures should be as
prescribed by the doctor.
Paracetamol:-
qIt works as both an analgesic and
antipyretic to treat aches, pains and reduce fevers.
qIts
side effect can be nausea, loss of appetite, stomach pain, discolored urine or
stool, jaundice etc.
qSome products that may interact : blood thinners,
isoniazid and ketoconzole.
qBefore taking it, consult your doctor if you
have a history of any of the following medical conditions: liver disease,
alcohol abuse.
Celecoxib (Celebrex):-
qIt is used in the treatment of pain,
inflammation, and stiffness of arthritis.
qStomach
upset or gas may occur.
qSome products that may interact : aliskiren,
ACE Inhibitors angiotensin II receptor blockers.
qShould not be prescribed to patients with
any type of allergy.
Aspirin (Acetylsalicylic Acid):-
Pharmacokinetics:-
qOrally Administered
qRapidly
absorbed
q70% is metabolized in the liver
qSlowly enters the brain but freely crosses
the placenta
qPoor solubility is the limiting factor
qSolubility is more at higher pH
qHalf life with low dose is 4h
qHalf life with high dose is over 15h
Adverse effects:-
Epigestric
distress, nausea, vomiting, gastric mucosal damage, peptic ulcer, hypersensitivity
Aspirin contraindications:-
qPeptic
ulcer
qUlcerative
colitis
qGout
qRenal failure
qHemophilias
Aspirin Doses (Oral):-
q As analgesic and
anti pyretic: 0.30.6 gm, 68 hours.
qAcute rheumatic fever: 75100mg/kg/day in
divided doses/4 days
qRheumatoid arthritis: 35mg/day
Ibuprofen
(Propionic Acid):-
Pharmacokinetics:-
qOrally Administered
qRapidly absorbed
qIt is supplied as a tablet potency of
200 to 800mg
qUsual dose is 400 to 800mg thrice a day
qMostly insoluble in water having pKa of
5.3
qRapidly biotransformed with a serum half
life of 1.8 to 2 hours.
qIbuprofen
tablets either under fasting conditions or immediately before meals yield
qQuiet similar serum concentrations time
profile.
Drug Interaction:-
qIbuprofen
has established drug interactions: lithium, warfarin, oral hypoglycemic, high
dose, methotrexate, anti-hypersensitiveness, angiotensin converting enzyme
inhibitors, B blockers and diuretics.
Ibuprofen contraindications:-
qHeart problem
qKidney disease
qLiver disease
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