Flashcards in NSAIDS & Paracetamol Deck (14)
What are NSAIDS?
"Non steroidal anti-inflammatory drugs" - they are used generally to treat mild to moderate somatic pain classically. They also inhibit COX1&2 (cyclooxygenase) which in turn decreases the conversion of Arachidonic acid into PGG2
What is an opioids used to treat?
Moderate to severe visceral and somatic pain
If COX is not inhibited by a NSAID what are the normal physiological functions of PGF2? And state any relevant contraindications in using a NSAID.
- Uterine contraction
Can't use a NSAID in pregnancy as it will stop uterine contractions; however, it could be applicable if the baby is predicted to be premature as it will slow contractions and keep the baby inside the mother longer.
If COX is not inhibited by a NSAID what are the normal physiological functions of PGE2? And state any relevant contraindications.
Vasodilation and Gastric cytoprotection
If COX is not inhibited by a NSAID what are the normal physiological functions of PGI2? And state any relevant contraindications.
Vasodilation and Gastric cytoprotection and decreases platelet aggregation (prostacyclin) by decreasing TXA2
If COX is not inhibited by a NSAID what are the normal physiological functions of TXA2? And state any relevant contraindications.
Describe the mechanism of Coxibs.
They are the newer and less available version of a NSAID. They act on COX2 and inhibit its activity thus causing a decrease in prostaglandins production from inducible constitutive functions of inflammation and a decrease in inflammation.
Describe the mechanism of NSAIDS.
Act on COX1&2. COX1 - inhibits the homeostatic prostaglandins which decreases gastrofunction, renal function and platelet formation. COX2 - inhibits constitutive functions in inducible inflammation which decreases those prostaglandins and inflammation.
What does COX1 do?
- Housekeeping enzyme
- Synthesis of housekeeping prostaglandins
- Gastric cytoprotection
- Platelet thromboxane A2
- Uterine contraction
- GIT contraction
What does COX2 do?
- inducible enzyme
- induces (cytokines, growth factors and bacterial lipopolysaccharides)
- increases prostaglandins at sites of inflammation
- housekeeping function in synthesis of PGI2 and renal function
How does COX work?
- it's product is tissue dependent
- functions within the endoplasmic reticulum
- COX1 has a narrower channel (Coxibs block only COX2 while smaller NSAIDS block both 1&2)
List the adverse drug reactions of non-selective COX inhibitors and name an example of one.
Effects as a result of PG inhibition:
- GIT problems (lesions, bleeding, ulceration etc)
- *Prolonged bleeding time
- Renal vasoconstriction (nephrotoxicity)
- *Pregnancy (prolonged gestation/bleeding)
Effects not related to PG:
- *Hypersensitivity reactions (rash/bronchospasm)
- Tinnitus (severe ringing in the ear)
- Drug interactions (anticoagulants, anti hypertensives and lithium)
List the adverse drug reactions of selective COX2 inhibitors.
Effects related to PG inhibition:
- increased TXA2 by inhibiting PGI2
- renal Vasculature constriction (decreases GFR)
- *myocardial infarction & stroke
Note: 50% less chance of a serious adverse effect over a non-selective COX inhibitor