PAIN/MSK DRUGS Flashcards
give 3 examples of NSAIDs
diclofenac
ibuprofen
naproxen
what are the 3 A’s of action of NSAIDs?
anti-pyretic
analgesic
anti-inflammatory
how do NSAIDs act as anti-pyretics?
inhibit prostaglandin production from hypothalamus. prostaglandins increase temperature
how do NSAIDs act as analgesics?
decrease peripheral prostaglandins that stimulate pain receptors
how do NSAIDs act as anti-inflammatory drugs?
cox 1 & 2 inhibition
suppress vasodilation & oedema
what particular type of pain are NSAIDs effective in and why?
MSK = acute gout, RA and osteoarthritis
what female condition is naproxen used in?
dysmenorrhoea
what other drug type are NSAIDs often given in conjunction with?
PPIs/H2 antagonists/gastro-protectives
give 4 hypersensitivity reactions that can occur with NSAIDs
bronchospasm
angioedema
urticaria
Fluid retention
give 4 diseases that contraindicate use of NSAIDs
Ischaemic heart disease Cerebrovascular disease Heart failure(*) Peptic ulcers Liver disease Renal failure Hypertension (Hypersensitivity can make it worse*)
why are NSAIDs contraindicated in the third trimester of pregnancy?
associated with failure of closure of ductus arterioles in utero (causes pulmonary hypertension)
why are NSAIDs contraindicated in hepatic failure?
increased risk of GI bleed and fluid retention
why are NSAIDs contraindicated in renal impairment?
increased water retention, can lead to renal failure
Which painkiller is NSAIDs used alternatively for?
paracetamol
Interaction of NSAIDS with what drugs increase the risk of
a) GI ulceration
b) GI bleed
c) renal impairment
aCorticosteriods and low dose aspirin
b) Anticouagulants, SSRI’s venlafaxine
c) ACE inhibitors and diuretics
What is the interaction between NSAIDS and warfarin?
Increase the chance of bleeding
What drugs does Nsaids reduce their therapeutic effect?
Anti hypertensives and diuretics
what kind of drug are codeine and morphine?
opiate analgesic
give 2 instances for when codeine is used except for pain
cough suppressant
diarrhoea
give an example of when morphine is used?
o MI, post-operative analgesia (acute pain)
o Acute pulmonary oedema
o Palliative care (relief of breathlessness)
o Chronic pain
give 6 abdominal contraindications of morphine
acute abdomen Dealyed gastric emptying alcohol intoxication hepatic failure Renal failure phaeochromocytoma
give 2 head &neck contraindications of morphine
raised ICP
head injury
give 1 respiratory contraindication of morphine
severe disease e.g COPD
Causing Cor pulmonale
name a chronic autoimmune disease that contraindicates use of codeine
myasthenia gravis
name a GI contraindication of codeine
obstructive or inflammatory bowel disease
give 2 endocrine contraindications of codeine
hypothyroidism
adrenocortical insufficiency
what is a respiratory side effect of opiates?
respiratory depression
give 2 circulatory side effects of opiates
hypotension
urinary retention
why shouldn’t opioids be used with hypnotics or alcohol?
enhance sedative effect
why shouldn’t opioids be used with cimetidine?
inhibits opioid metabolism
what is an opiate overdose reversed with?
naloxone
how long can it take for tolerance/dependance to begin in opiate use?
a) 5 days
b) 2 weeks
c) 5 weeks
d) 5 months
b) 2 weeks
what kind of COX inhibitor is paracetamol?
COX-2 specific
why does paracetamol have less anti-inflammatory action than NSAIDs?
CNS specific, so doesn’t act on peripheries
give 3 tell-tale signs of paracetamol overdose
liver damage
nausea vomiting
right subcostal pain
why shouldn’t paracetamol be used with coumarins?
increase anti-coagulant effect
why should’t paracetamol work with carbimazepine and phenytoin
increases metabolism of paracetamol
what is the antidote for paractamal overdose?
acetylcystiene
give an example of a xanthine-oxidase inhibitor
allopurinol
Febuxostat
what enzyme and subsequent product are inhibited by allopurinol?
xanthine oxidase enzyme is inhibited in metabolising xanthine (from purine) to uric acid. Consequently reduction in plasma uric acid levels and therefore reduces precipiation of uric acid into joints and kidney
what common MSK condition is an indication for use of allopurinol?
To prevent gout
give 2 other indications for use of allopurinol
- To prevent hyperuricaemia and tumour lysis syndrome associated with chemotherapy
- Prevent uric acid and calcium oxalate renal stones
give a hepatic side effect of allopurinol
jaundice
give 2 complications of hypersensitivity syndrome of allopurinol? rare and life threatening
lymphadenopathy
eosinophilia
fever
Involvement of other organs such as skin and liver
why shouldn’t allopurinol be used with thiazide diuretics or ACE inhibitors?
increase risk of hypersensitivity reaction
Why should mercaptopurine and azathioprine dose be reduced when taking allopurinol?
Increase toxicity levels
How does NSAIDS prevent the production of prostagladins from arachidonic acid?
By inhibiting cyclooxygenase
What is the action of Cox-1?
Constitutive form
Produces prostagladins that preserve the integrity of the gut mucosa, maintains renal perfusion and prevents thrombus formation on vascular endothelium
What is the actions of Cox-2?
Inducible form
Inflammatory stimuli causes the production of prostagladins that cause inflammation and pain
Inhibition of which cox gives therapeutic benefit and which one gives adverse effects of NSAIDs?
Cox-1 = adverse effects
Cox 2= therapeutic effects
What are the pros and cons of a Cox-2 inhibitor?
It has less GI side effects but increases risk for cardiovascular event
Why shouldn’t patient with peptic ulcers have NSAIDS?
Increase risk of GI bleed
How does morphine work?
A strong opiate which acts on opiate receptors in the CNS. It helps to relieve pain but also blunts the medulla response to hypoxia and hypercapnia which improves respiratory response and breathlessness.
Which two cardiac conditions is morphine used for?
MI and acute pulmonary oedema
What is the treatment for acute pulmonary oedema?
Morphine Nitrate Furosemide Oxygen Salbutamol if wheeze is present
What is a synthetic analogue of codeine?
Tramadol which is used for moderate pain
When prescribing a regular opiates what should you prescribe with it?
Laxatives
Should you give dihydrocodeine or codeine via IV route?
No never as can cause a similar affect to anaphylactic shock
Why should patients who are epileptic not be given Tramadol?
It reduces seizure threshold
Why should you not give morphine to someone with biliary colic?
Can cause spasm of the sphincter of Oddi and therefore increase pain
Why should you not give naproxen to a elderly patient?
It’s a steroid and not good for AKI patients causing fluid retention
Why shouldn’t codeine be used in elderly patients?
Constipation and they have poor renal function, so reduced excretion and therefore cause side effects
What are common GI side effects of opiates?
N&V
Abdo pain
Constipation
What general side effects do opiates have?
Hallucinations Dependency Hypothermia Hypersensitivity Drowsiness
What are the circulatory effects of paracetamol?
Hypotension and flush
What is the first line analgesia for acute and chronic pain?
Paracetamol
What is paracetamol used for?
Pain, Pyrexia and associated symptoms
How is paracetamol metabolised?
Cytochrome p450
What action should be taken when taking allopurinol and Capecitabine?
Stop taking Capecitabine
What is a common side effect of allopurinol?
Rash
What commonly occurs in the 1st month of taking allopurinol?
Acute attack of gout
What should you take with allopurinol in the 1st month to reduce the risk of acute attack of gout?
NSAIDS or colchicine
What are the contradictions of using allopurinol?
Reccurent skin fash
Hypersensitivity
liver or renal impairment as it is metabolised by the liver and excreted by the kidney
Should you start taking allopurinol during a acute attack of gout?
No you should not, but do continue taking if you began before the attack occured due to control serum levels of uric acid
How should you take allopurinol?
Orally and after food
During a hypersenstivity reaction of allopurinol what can occur?
Rash, fever, leukopenia, eosinophilia
How does methotrexate work?
It inhibits dihydrofolate reductase in converting dietary folic acid into tetrahydrofolate (FH4)
FH4 is needed for DNA and protein synthesis and therefore prevents cellular replication
What are the properties of methotrexate?
Anti inflammatory and immunosuppresants
what diseases is methotrexate used for?
Disease modifier for RA
Chemotherapy for leukaemia, lymphoma and solid tumours
Sever psoriasis and psoriatic arthritis
How is methotrexate administrated?
once Weekly
Orally for autoimmune disease
IV for chemo
What do you take with methotrexate and why?
Take folic acid the other 6 days to keep cells health
Hydration and urinalysis alkalinisation to enhance the excretion of methotrexate
What are the contradictions of methotrexate?
Pregnancy as its teratogenic
Renal failure
Abnormal liver function as can cause hepatotoxicity
Peptic ulcers, UC and diarrohea
What precautions need to be taken around methotrexate and pregnancy?
Use contraceptives 3 months prior and after treatment
What are common side effects of short term use of methotrexate?
Mucosal damage
Bone marrow suppression
What side effects do you get with methotrexate over dose?
Hepatotoxicity
Renal failure
Neurological changes–> headache, seizures and coma
What are the side effects of long term use of methotrexate?
Pulmonary fibrosis when given for RA
hepatic cirrhosis
How does NSAIDS, aspirin and penicillin increase methotrexate toxicity?
By inhibiting renal excretion of methotrexate
What drug interactions with methotrexate increase risk of haematological abnormalities?
Trimethoprim and phenytoin
What is the drug interaction between methotrexate and clozapin?
Neutropenia
What can side effect of rash from taking allopurinol be indication of?
Stevens–Johnson syndrome or toxic epidermal necrolysis.
