Gastroenterology: Pharmacology - Drugs used to treat IBD Flashcards
Pharmacodynamics of 5-aminosalicylic acid
Uncertain, likely modulates inflammatory mediates from COX and LOX pathways
Clinical uses of 5-ASA
Primarily UC
Adverse effects of 5-ASA
Predominantly seen with sulfasalazine
Nausea and GI upset
Headache, myalgias, malaise
Bone marrow suppression
Oligospermia
Rarely hypersensitivity may cause fever, exfoliative dermatitis, pancreatitis, pneumonitis, haemolytic anaemia, hepatitis, pericarditis
Mechanism of action of sulfasalazine, mesalamine
5-ASA containing
Mechanism of action of azathioprine, 6-mercaptopurine
Purine analogues with immunosuppressive effects
Adverse effects of purine analogues
Nausea and vomiting
Bone marrow suppression
Hepatotoxicity
Interacts with allopurinol: reduces XO catabolism of purine analogues, increasing the concentration of active drug and therefore risk of adverse effects including leukopenia
Mechanism of action of methotrexate
Inhibits dihydrofolate reductase, important for production of thymidine and purine
Inhibits cellular proliferation at higher doses (in chemotherapy)
Adverse effects of methotrexate. How can the risk of these adverse effects be minimised?
Bone marrow depression
Megaloblastic anaemia
Alopecia
Mucositis
Risks minimised by co-administration of folate
Mechanism of action of infliximab, adalimumab, certolizumab
Monoclonal IgG1 Ab to TNF
Adverse effects of anti-TNF drugs. How can some of these risks be reduced?
Risk of infection due to suppression of TH1 inflammatory response: pre-testing for latent TB needed
Development of antibodies to the antibody (ATA): more common with episodic instead of regular scheduled injections
Acute adverse infusion reactions: more common with second or subsequent infusions
Delayed serum sickness-like reaction
Severe hepatic reactions
Psoriatic skin rashes
What adverse effect seen with anti-TNF drugs reduces their efficacy?
Development of antibodies to the antibody (ATA)
Mechanism of action of natalizumab, vedoliazumab
Anti-integrin
