Pharmacology of Arthritis Flashcards
What are the two main categories of drugs for arthritis treatment?
Symptom relief
Disease modifiers
Name four groups of drugs which can be used for symptom relief?
- Paracetamol
- Opiates
- NSAIDs
- Atypical analgesics
Name two groups of drugs which are disease modifiers?
- DMARDs
- Biologics
What is the role of paracetamol?
Pure analgesic (not anti-inflammatory)
Does paracetamol have many side effects?
Not really
When does paracetamol become dangerous?
When overdosed
Does paracetamol cause renal impairment?
No
Is paracetamol safe to use in pregnancy?
Yes
What is the first step of pain relief medication? Give examples.
Non-opioid: paracetamol, aspirin, NSAID
What is the second step of pain relief medication? Give examples.
Weak opioid: codeine +/- non-opioid
What is the third step of pain relief medication? Give examples.
Strong opioid: morphine +/- non-opioid
Give two examples of atypical analgesics?
Amitriptyline and gabapentin
What type of drug is amitriptyline?
Tricyclic anti-depressant
What type of pain is gabapentin good for?
Neuropathic pain
What are the actions of NSAIDs?
Analgesic and anti-inflammatory
When are NSAIDs used?
Relief of acute pain, not much use in the long term
Why are NSAIDs not useful in the long term?
Lots of side effects
Give 3 examples of NSAIDs?
Ibuprofen, naproxen, diclofenac
Give 5 GI side-effects of NSAIDs?
- Peptic ulcers
- Dyspepsia
- Oesophagitis
- Gastritis
- Bowel ulcerations
Give 5 non-GI side effects of NSAIDs?
- Fluid retention
- Exacerbation of asthma
- Rash
- Increased CV risk
- Renal impairment
What kind of drug is celecoxib?
COX2 inhibitor, a type of NSAID
What do COX2 inhibitors target?
Cyclooxygenase-2, an enzyme responsible for inflammation and pain
What is the major advantage of COX2 inhibitors?
They have no risk of peptic ulceration
What is the major disadvantage of COX2 inhibitors?
Greatly increase CV risk
Who are COX2 inhibitors given to?
People with no other CV risk factors
What is the number 1 treatment for inflammatory arthritis?
DMARD therapy- methotrexate
What drug should be co-administered with DMARDs?
Steroids
Are the steroids which are given alongside DMARDs continuous?
No
What effect do DMARDs have?
Halt disease progression, anti-inflammatory
How soon do DMARDs need to be started to achieve full effect?
Within the first 3 months
Do DMARDs have any analgesic effects?
No
How are patients on DMARDs monitored?
Blood tests every 4 weeks, especially FBC and LFTs for low white cell count or liver damage
Once there is joint damage, can it ever be regained?
No
What are the indications for using DMARDs?
Active inflammatory diseases where the benefits will outweigh the risks
Name 4 DMARDs?
- Methotrexate
- Sulphasalazine
- Leflunomide
- Hydroxychloroquine
What is the mode of action of methotrexate?
Folate antagonist- blocks dihydrofolate reductase
What supplements must always be given with methotrexate?
Folic acid
How can methotrexate be administered?
Oral or subcutaneous injection
Give 4 uses of methotrexate?
- RA
- Psoriatic arthritis
- CTD
- Vasculitis
What are the major worries with methotrexate, that blood tests are taken to monitor?
- Leukopenia/thrombocytopenia i.e. weakened immune system
- Myelosuppression (bone marrow suppression)
- Hepatotoxicity (hepatitis/cirrhosis)
What should be limited to help avoid hepatotoxicity when taking methotrexate?
Alcohol
What lung problems can methotrexate cause? When do these present?
Pneumonitis (fairly soon after starting) Pulmonary fibrosis (in older patients who have been on the medication for a long time)
Patients are told to report if they feel what to help avoid progression of pneumonitis?
Dyspnoea or have a cough
What are some general side effects of methotrexate?
Rash, mouth ulcers, nausea, diarrhoea
What is the rule with methotrexate and pregnancy?
Teratogenic- must be stopped in both males and females 3 months before conception (and contraception used in that time)
What type of drug is sulphasalazine?
Aminosalicylate
How is sulphasalazine taken?
Orally
What are the side effects of sulphasalazine?
- Nausea, rash, mouth ulcers
- Neutropenia and thrombocytopenia
- Hepatitis
- Temporary oligozoospermia
- Stevens-Johnsons Syndrome
- Severe depression
What does leflunomide inhibit?
Dihydroorotate dehydrogenase
What is the major side effect of leflunomide?
Interstitial lung disease
Apart from ILD, what are some other side effects of leflunomide?
- Hepatotoxicity
- Hypertension
- Alopecia, eczema
- Pancytopenia
- GI upset
What are the rules with leflunomide and pregnancy?
Also teratogenic, with a long half-life so will need a wash out if the patient wants to get pregnant
What drug should be used next if methotrexate causes too many side effects?
Leflunomide
What type of drug is hydroxychloroquine?
Anti-malarial
When is hydroxychloroquine mainly used?
CTD (e.g. SLE)
What is the effect of hydroxychloroquine on joint damage?
No effect
Give 4 side effects of hydroxychloroquine?
- Irreversible retinopathy
- Corneal deposits
- Haemolytic anaemia
- GI upset
Give two DMARD drugs which are used rarely now?
IM gold
Oral penicillamine
Azathioprine is a derivative of what?
Mercaptopurine
What are some side effects of azathioprine?
- Myelosuppression and neutropenia
- Hepatotoxicity
- Pancreatitis
- GI upset
Is azathioprine teratogenic?
Yes
How do biologics work?
Drugs are designed to target specific aspects of the immune system which are implicated in a disease
If patients are going to respond to biologics, how will this occur?
Very quickly with a vast improvement
How are most biologics given?
Subcutaneous injection every 1-2 weeks
Give 2 examples of anti-TNFs which are given subcutaneously?
- Adalimumab
- Etanercept
What is a side effect of etanercept?
Demyelination
What is an example of an anti-TNF given IV?
Infliximab
What is TNF?
A cytokine which is a driving force in inflammation
Who are given biologics?
Those with a DAS28 score of > 5.1 and have been on at least two DMARDs including methotrexate
What is the major risk of biologics?
Immunosuppression
What must all patients be screened for before starting biologics? Why?
TB- biologics can cause reactivation of latent TB
Biologics cause increased risk of which cancer?
Melanoma
What cardiac effect do biologics have?
Worsen heart failure
Are biologics teratogenic?
No
What is rituximab and when is it used?
A monoclonal antibody against B cells so can be used in any condition where autoantibodies are present
What does tocilizumab do?
Inhibit IL-6
What does abatacept do?
Blocks full activation of T cells so they cannot interact with B cells
What does ustekinumab do?
Inhibit IL-12 and IL-23
What does secukinamb do?
Inhibit IL-17
IL-12, IL-23 and IL-17 blockers are useful in what condition? Why?
Psoriatic arthritis as this is T cell driven
What does ciclosporin do?
Blocks cytotoxic T cell activation
What are some side effects of ciclosporin?
- Immune suppression
- Nephrotoxicity
- Hepatotoxicity
- Hypertension
- GI upset
What is a side effect of colchicine?
Diarrhoea
What do steroids do to bones?
Loss of bone density so can give osteoporosis
What supplements should be given when takin steroids?
Calcium and vitamin D
How do steroids contribute to the development of diabetes?
Cause weight gain due to increased appetite and fluid retention
What drug should be used for gout prophylaxis in patients with kidney disease?
Febuxostat
When should you use febuxostat with caution?
Ischaemic heart disease
What is a side effect of allopurinol?
Vasculitis like rash
Who should be given lower doses of allopurinol?
Elderly and renal impaired (more likely to get the rash)
What happens on interaction of allopurinol and azathioprine?
Irreversible bone marrow suppression
You can prescribe allopurinol up to doses of what?
900mg
Patients on methotrexate who want to conceive can be switched to which drugs?
- Sulphasalazine
- Biologics (if they meet the requirements)
What happens to RA in pregnancy?
It often gets better but then dips again after birth