SPR L2 Inflammation, NSAIDS and DMARDS Flashcards
SPR L2 Inflammation and NSAIDS and DMARDS
Learning Outcomes
for general perusal
- Understand what NSAIDs are and their mechanism of action
- Appreciate the different roles of COX-1 versus COX-2 inhibition
- Be able to list the main medical uses of NSAIDs with examples
- Be familiar with the potential side-effects/contraindications of NSAIDs
- be able to describe DMARDs, giving three examples and their MOA
- have sufficient information on NSAIDs/DMARDs/Steroids to understand clinical cases presented in the Tutorials
Non-Steroidal Anti-Inflammatory Drugs
- Generally describe this class of drug
- What are they used to treat?
- However, what is seen with this class of drug?
- Very widely used, aspirin-like drugs, greater than 50 NSAIDS on the market - diverse range
- a range of conditions such as inflammation, fever, pain, muscle injury, sprains, fractures etc.
- significant side-effects

Give examples of Important NSAIDs commonly in use in medicine
- aspirin
- ibuprofen
- Naproxen (Alleve)
- Indomethacin - powerful NSAID with wide ranging use/side-effects
- Diclofenac
- Paracetamol
What is the mechanism of action of NSAIDs?
NSAIDs work by inhibition the action of cyclooxygenase (COX) enzymes, lowering levels of prostaglandins e.g. PGE2, PGI2
2 main isoforms: COX-1 and COX-2

Mechanism of Action of NSAIDS
What do prostaglandins cause?
- vasodilation
- oedema
- pain (increasing Bradykinin-mediated nociception)
Cyclooxygenase (COX) Enzymes
- What are the two main isoforms?
- What action do these enzymes have?
- Where is COX-1 expressed?
- What does it do?
- Prostaglandins produced by COX-1 are involved in what?
- Where is COX-2 expressed, what is it?
- COX-1 (constitutively active) and COX-2 (inducible)
- use arachidonic acid to generate PGs and TXA2
- expressed in most tissues including platelets
- general “housekeeping” COX enzyme
- a) protection of gastric mucosa
b) platelet aggregation
c) renal blood flow autoregulation
- expressed in activated inflammatory cells e.g. basophils, eosinophils, inducible form of enzyme

Cyclooxygenase Enzymes
- COX-1 and COX-2 have approximately __% sequence identity?
- What similar ability do both have?
- What defines their different roles/side-effects?
- What are most NSAIDs?
- 60%
- ability to induce arachidonic acid oxidation
- differences in COX tissue expression
- non-selective between COX-1 versus COX-2
NSAIDs work by inhibiting COX-1 and COX-2
General Rule of Thumb
- What do the majority of anti-inflammatory effects of NSAIDs occur via?
- What do most side-effects of NSAIDs occur via?
- COX-2 inhibition
- COX-1 inhibition

Main Pharmacological Actions of NSAIDs
- What are these?
- What are the main side-effects?
- anti-inflammatory, analgesic, anti-pyretic
- gastric irritation, compromised renal blood flow, increased bleeding, increase risk of MI (COX-2).
Effects and side-effects arise from the primary action of the NSAIDs in different tissues
Main Pharmacological Actions of NSAIDs
1. Anti-inflammatory
- How does this come about?
- What is this clinically useful in?
- NSAID inhibition of COX-2 predominantly
- Inflammatory arthritis Dental pain Oro-facial pain Post operative pain Bone metastases in cancer
NOTE: NSAIDs have no effect on the disease causing the inflammation e.g. RA
Main Pharmacological Actions of NSAIDs
2. Analgesic (for mild/moderate pain due to inflammation or tissue damage)
- What is the mechanism for this action?
- What are they effective in?
- How do they help headaches?
- How are they useful in surgery?
- decreased Prostaglandins, reduced sensitization of Bradykinin nociception
- Effective in arthritis, muscle pain, toothache, dysmenorrhea, postpartum pain, cancer metastasis in bone pain
- NSAIDs reduce PG-induced vasodilation in brain
- reduce postoperative pain, reduce the amount of opioids needed by up to 30 %
Main Pharmacological Actions of NSAIDs
3. Anti-pyretic
- How is this brought about?
- How?
- Outline the pathological pyretic response that brings about a fever?
- decreased PG production in the hypothalamus. “NSAIDs reset the body’s thermostat” (paracetamol primarily used)
- vasodilation, sweating. NB - no effect on normal body temperature
- Bacteria => endotoxin => increased IL-1 from macrophages (pyrogen) => Increased PGE2 production in the hypothalamus via COX-2 action => fever

Other Clinical Uses of NSAIDs
- Outline the main clinical uses of NSAIDS
Give TWO other uses
- Anti-inflammatory, Analgesic, Anti-pyretic
* Anti-platelet: Aspirin (COX-1 inhibition)- Stroke prevention
- MI prevention
- Unstable angina
- Deep venous thrombosis (DVT) prevention
* Colon cancer prevention: low dose, long-term (5 years) aspirin may reduce the risk of colon and other GI cancers
Aspirin: Nature’s miracle drug
- What is it derived from?
- Aspirin is the only NSAID that…?
- Which does it inhibit?
- Which does it have more affinity for?
- Summarise the history of the drug
- the bark of the willow tree
- irreversibly inhibits COX
- Inhibits both COX-1 and COX-2
- but has a greater affinity for COX-1
- See picture

Side-effects of NSAIDS
high burden of side-effects with NSAIDs
- What are these side effects due to?
- What do common side effects include?
- due to the inhibition of COX activity and PG production in non-inflammatory tissues
- GI disturbances
- Adverse Renal Effects
- Rashes
- CNS effects
- Bone Marrow effects
- Aspirin sensitive asthma
- Liver toxicity (paracetamol)
Side-effects of NSAIDS
Gastrointestinal Disturbances
- What are these usually in the form of?
- What occurs in approroximately 1/3 of patients on NSAIDS
- What is the cause of the GI disturbance seen?
- How can this effect be limited?
approx 100,000 people in the USA hospitalised as a result of GI effects of NSAIDs.
- 15 % of these people die - who do these tend to be?
- perforations, ulcers, bleeds
- diarrhoea, constipation, nausea, vomiting
- NSAIDs inhibit gastric COX-1 which generates PGE2 that inhibits acid secretion from the parietal cells in the stomach
- limit this effect by giving Misoprostol which is a PGE2 analogue (avoid in pregnancy!!) other types of ulcer protection also used (PPIs, antacids)
- older patients taking NSAIDs for arthritis
Side-effects of NSAIDS
Adverse Renal Effects
In healthy patients, there is no risk to kidney function
- Who is at risk? Of what?
- What is the cause?
- What is the mechanism?
- What does the NA+ retention lead to?
- What was also seen with Phenacetin (now withdrawn)
- patients with compromised renal function - NSAIDs can cause acute renal failure. ALSO: Neonates, elderly, heart, liver, kidney disease patients at risk of this side-effect
- COX inhibition, reduced PGE2, PGI2 production, altered renal blood flow
- see picture
- Hypertension
- analgesic nephropathy also seen

Drug Interactions of NSAIDS
- What is there increased risk of when using more than one NSAID, especially if one is aspirin?
- When is there increased risk of GI bleeding?
- What shows reduced effectiveness with NSAIDs?
- increased risk of bleeding
- with anticoagulants, and anti-depressants (aspirin and SSRIs ,venlafaxine)
- diuretics and antihypertensive agents
Drug Interactions of NSAIDs
Stevens-Johnson Syndrome-an rare allergic drug reaction (Erythema multiforme major))
- What is this?
- What NSAID is most likely to be administered to young children?
- Hypersensitivity reaction to drugs-penicillin, sulfonamides. Can be fatal.
- ibuprofen or paracetamol
When are NSAIDS contraindicated?
- Patients with Peptic Ulcer Disease
- Patients with a history of GI bleed
- Those receiving anticoagulants
- caution in patients with renal impairment, heart failure or hypertension
- used with caution in pregnancy, especially during the third trimester (can cause closure of the ductus arteriosus in utero, PH in baby) => EOP 3
- ibuprofen can be used to close the PDA in premature infants (JAMA)
- Those with a previous history of allergic reactions e.g. asthma
Paracetamol: NSAID or not?
Paracetamol (acetaminophen)
- What actions does it have?
- What may it be related to?
- Are there any GI effects?
- What is a problem with this drug?
- What is the toxic dose of paracetamol?
- What does it cause?
- How long does this take to occur?
- What can overdose be treated with?
- excellent analgesic and anti-pyretic effects, little anti-inflammatory effects
- the inhibition of COX-3 (a splice variant of COX-1) in the CNS
- no real side-effects in the GIT, platelets-so is it an NSAID at all?
- problems related to “over the counter” availability of the drug
- 10-15 grams = > fatal hepatotoxicity
- depletion of glutathione (GSH), accumulation of toxic intermediates in liver, necrosis and liver failure
- fatal hepatotoxicity after 24-48hr
- can be treated within 12 h of ingestion with acetylcysteinse (↑GSH)

Selective versus non-selective COX inhibitors
if the side-effects of NSAIDs are due to COX-1 inhibition, why not make COX-2 specific inhibitors?
- 2 COX-2 specific inhibitors developed for arthritis, colon cancer
- rofecoxib (Vioxx, Merck)
- celecoxib (Celebrex, Pfizer)
- rofecoxib reduced the incidence of GI bleeds by 50 %
-
increased risk of myocardial infarction/stroke - drug withdrawn by Merck in 2004
- Why? Increased arterial BP, increased platelet count
- Merck paid $5 billion in class action lawsuit (2007), $1 billion in civil and criminal fines (2011)
Reminder of Drug Class Recognition
Give examples of the following drugs:
- ACE Inhibitors
- ARBs
- Ca2+ Channel Blockers
- COX-2 Inhibitors
- Enalapril, Lisinopril
- Losartan, Valsartan
- Amlodipine, Aranidipine
- Celecoxib, Paracoxib
Selective versus non-selective COX inhibitors
Question: if the side-effects of NSAIDs are due to COX-1 inhibition, why not make COX-2 specific inhibitors?
- Give examples ofC OX-2 inhibitors in use today
- What are they used for?
- What needs to be observed?
- Why?
- Celecoxib (Celebrex, rare cases of RA)
Parecoxib
Etoricoxib
- used for the treatment of arthritis
- monitor for adverse CV events, still get some effects on GIT (ulcers), kidney, skin
- probably due to some inhibition of COX-1 (selective, not specific)

NSAID selectivity for COX enzymes
- Give an example of a COX-1 Inhibitor?
- and of COX 1&2 Inhibitors?
- and of COX 2 Inhibitors?
- Aspirin
- Ibuprofen**, Naproxen**, Indometacin***
- Celecoxib
Etoricoxib

Disease-Modifying Anti-Rheumatic Drugs (DMARDs)
diverse set of unrelated agents that have different mechanisms of action, all have the potential to improve the symptoms of rheumatoid arthritis
- What do Corticosteroids and NSAIDs do?
- What to DMARDS do?
- give reduced pain/inflammation associated with RA
-
decrease disease severity, improve symptoms
- decrease number of swollen joints
- reduced pain score
- decrease serum levels of IgG
Examples of DMARDs
- Name the older drugs not commonly used for RA
- Name the common drugs for RA
- Gold, D-penicillamine, Sulfasalazine, Hydroxychloroquine
- Methotrexate, Leflunomide
Azathioprine-look up yourselves
Infliximab (anti-TNFa antibody)
DMARDs
Methotrexate
- What is it? Outline its mechanism of action.
- What is it used as?
- What is the ROA?
- When is the onset of action?
- What are the potential side effects?
- What therapy is common?
- When is it NOT to be used? Why?
- folic acid antagonist with immunosuppressant activity. potent anti-rheumatoid activity, common first-choice DMARD. (see picture)
- used to treat Crohn’s disease, also used as an anti-metabolite in cancer therapy, inhibits DNA synthesis
- orally, im, iv
- 6 week onset of action
- blood disorders, liver cirrhosis, nephrotoxicity, GIT damage, neural tube defects
- long term therapy common (>5 years), most commonly used DMARD for RA
- not to be used in pregnancy/avoid conception 3 months post therapy due to teratogenic effects

DMARDs
Leflunomide
- What is this?
- What is it’s mechanism of action?
- How is it absorbed orally?
- Describe the half life
- What are the main side effects?
- What is essential?
- What is the onset of action?
- Who can it be given to?
- When is it contraindicated
- What is the washout period? What is the general rule as a result?
- immunosuppresant drug, specific inhibitor of activated lymphocytes
- Inhibitor of dihydroorotate dehydrogenase, blocks pyrimidine production, blocks clonal expansion of T-cells, other cells can bypass this blockade
- well absorbed orally
- long half-life (4-28 days)
- anaemia, hepatotoxicity, diarrohea, nausea
- blood monitoring essential
- onset of action in 4 weeks
- patients who don’t respond to MTx
- pregnancy, breast feeding
- Needs a 2 year wash out period, best avoided in premenopausal women
DMARDs
Anti-tumour necrosis factor-a (TNFa) antibodies
- What is
- Infliximab
- Etanercept - What is it used for?
- When are these drugs used?
- Infliximab can be used in combination with what?
- What are the s/e’s?
- What are the disadvantages
- monoclonal antibody against TNFa - recombinant TNFa receptor-IgG fusion protein
- used for RA, Crohn’s Disease
- NICE guidelines-use these drugs after at least 2 DMARDs have been tried
- with MTx - If MTx cant be used due to C/I, use etanercept as monotherapy
- reactivation of TB, increased infections
- very expensive drugs: one year of therapy costs about £20,000 per patient, but has been a major therapeutic advance in the treatment of rheumatoid arthritis

Steroid v NSAID v DMARD in RA
How are the following drugs used in RA…
- NSAIDS?
- DMARDS?
- Steriods?
- can provide rapid pain relief
- could be started at the same time as NSAIDS, takes 4-6 weeks before effects seen
- can be used but care should be taken due to potential side-effects
remember the contraindications and potential side-effects
Learning Outcomes
for general perusal
- Understand what NSAIDs are and their mechanism of action
- Appreciate the different roles of COX-1 versus COX-2 inhibition
- Be able to list the main medical uses of NSAIDs with examples
- Be familiar with the potential side-effects/contraindications of NSAIDs
- be able to describe DMARDs, giving three examples and their MOA
- have sufficient information on NSAIDs/DMARDs/Steroids to understand clinical cases presented in the Tutorials