CPT revision Flashcards
What is the pathophysiology of rheumatoid arthritis?
Hypertrophy of joint synovial to form pannus.
Infiltration of inflammatory cells, release of pro-inflammatory cytokines.
Pannus erodes cartilage and bone
What criteria aids RA diagnosis?
Morning stiffness > 1 hour > 3 joints affected Hand joints affected Symmetrical Rheumatoid nodules Serum rheumatoid factor
What are the side effects of corticosteroids?
Hypertension Osteoporosis Weight gain Bruising Hyperglycaemia Infections Skin thinning
What is the MOA of corticosteroids?
Inhibit T cell activation
Prevent IL-1 and IL-6 synthesis by macrophages.
What SE are common to all immunosuppressants?
Hepatitis
Infection risk
Malignancy
BM suppression
Name 4 highly protein bound drugs.
NSAIDS
Methotrexate
Warfarin
Sulphonylureas
What tests are necessary to monitor if giving calcinuerin inhibitors?
eGFR - renal toxicity
BP - accelerates hypertension
What tests must be done before methotrexate treatment?
CXR - pnueumonitis
FBC
LFT
What are the side effects of methotrexate, how can they be reduced?
Mucositis BM suppression Liver cirrhosis, hepatitis Lungs - pneumonitis Teratogenic
Folic acid reduces mucositis + BM suppression.
Which DMARD has poor intestinal absorption and can therefore be used to treat IBD?
Sulphasalazine
What is the MOA of sulphasalazine?
Inhibit T cell proliferation and IL-2 synthesis
Decrease neutrophil chemotaxis and degranulation.
Which DMARD causes haemorrhagic cystitis, how can this be minimised?
Cyclophosphamide - acrolein metabolite is toxic to bladder epithelium.
Mesna and hydration - mesna binds bladder ep and prevents interaction
What is the MOA of anti-TNF alpha?
Inhibit cytokine cascade and leukocyte recruitment
Decrease angiogenesis
Give 4 conditions methotrexate is used to treat.
Cancer
RA
Psoriasis
Crohn’s
How can oseltamivir resistance arise?
Neuroaminidase enzyme mutation
Which viral enzyme activates aciclovir?
thymidine kinase
What is the MOA of nucleoside RT inhibitors and non-nucleoside RT inhibitors?
NRTI - analogues of nucleosides, bind and halt reverse transcriptase.
NNRTI - non-competitive inhibition of HIV reverse transcriptase. Bind to allosteric sight and cause conformational change, inhibiting RT.
What is the MOA of protease inhibitors?
Inhibits protease enzyme responsible for cleavage of the viral polyprotein into a number of essential enzymes and proteins.
What is the MOA of integrase inhibitors?
Inhibits insertion of viral DNA into host genome
What is the advantage of virus resistance testing?
Increases outcome
Reduces costs
No ADRs of ineffective therapy
Decreases resistant virus pool
How is virus resistance testing done?
Phenotypic characterisation
What advice should you give to patients when prescribing warfarin?
Risk of bruising and bleeding
Teratogenic
Avoid NSAIDs and aspirin - bleeding risk
Food - too many leafy greens reduce effectiveness
What should you check before administering heparin?
Renal function - renal clearance
What are ADRs of heparin?
Bleeding
Osteoporosis
Thrombocytopenia
What is used to reverse heparin if actively bleeding?
Protamine sulphate - dissociates heparin from antithrombin III. Irreversibly binds.
Name 3 anti-platelet drugs and their MOA.
Aspirin - COX - 1 inhibitor, inhibits thromboxane A2 synthesis
Clopidogrel - ADP antagonist
Dipyridamole - phosphodiesterase inhibitor
What are the benefits of anti platelet drugs?
Decreased risk of intracranial haemorrhage
No monitoring
What are the disadvantages of anti-platelet drugs?
Increased risk GI bleed
May not have reversal agent
Which study designs are best for establishing a temporal sequence?
RCT
Prospective cohort
Poor -case-control, cross-sectional
What is a side effect of H2 antagonists in males?
Gynaecomastia
What are side effects of proton pump inhibitors?
Diarrhoea
Infection risk
C.difficile risk
Osteoporosis - increase pH, decrease Ca absorption
What are some causes of GORD?
Obesity - raised intrabdo pressure
LOS weakness
Delayed gastric emptying
Hiatus hernia
What is the treatment for peptic ulcer?
Stop NSAIDs if can
H2RA or PPI for 6 weeks
H-pylori eradication if relevant
What are SE of B2 agonists?
Tremor
Tachycardia, palpitations
What is the MOA of montelukast?
Leukotriene receptor antagonist
Mast cells release leukotriene - mucus secretion, mucosal oedema, bronchoconstiction
SE of LTRA?
Fever
Angioedema, Arthralgia, Anaphylaxis
Dry mouth
What is the MOA of methylxanthines?
Inhibit phosphodiesterase, increase cAMP
Inhibit adenosine receptors
What are the characteristics of methylxanthines?
Narrow therapeutic window - monitoring required
Poor efficacy
CYP450 metabolism - interactions
What are the SE of aminophylline?
Seizures, convulsions
Arrhythmia
Name 2 long acting anticholinergics?
Tiotropium bromide
Ipratropium bromide
What is the MOA of voltage gated Na blockers when treating epilepsy?
Bind to depolarised Na channels and prolong inactivation state to inhibit spread of hyperactivity.
Detach once membrane potential normal again = use dependent.
Name 4 VGSC blockers for epilepsy?
Carbamezepine
Phenytoin
Lamotrigine
Valproate
Which anti-epileptic drug half life reduces with repeated doses.
Carbamezepine - induces CYP450 enzymes which metabolise it.
Which AEDs are highly protein bound?
Carbamezepine
Phenytoin
Valproate
BZDs
What is a rare but serious ADR of carbamazepine?
Bone marrow suppression - neutropenia
What ADRs are associated with AEDS?
CNS - dizziness, drowsiness, ataxia
Rashes
Nausea and vomiting
Outline the pharmacokinetics of phenytoin, what is the significance of this?
Non-linear at therapeutic conc - t/12 unpredictable, monitoring required.
Highly protein bound
CYP450 - enzyme inducing - COCP, warfarin (not itself)
How are phenytoin and valproate levels monitored?
Salivary levels - indication of free plasma level
What is the MOA of lamotrigine?
Na channel blocker
Ca channel blocker