Rheumatology Drugs Flashcards
What class of antibiotic does ceftriaxone belong to
cephalosporins
Explain the spectrum of activity of cephalosporins
increasing generations of cephalosporins have increasing gram negative activity
Explain the MOA of cephalosporins
B-lactam ring inhibits cross-linking of peptidoglycan cell walls leading to osmotic swelling and lysis
What is the most common side effect of cephalosporins
GI Upset and antibiotic associated colitis
Explain antibiotic associated colitis
Cephalosporins kill normal flora, this can lead to overgrowth of c.difficle and antibiotic associated colitis
What is the main complication of antibiotic associated colitis
Toxic megacolon and subsequent perforation
What is another side effect of cephalosporins and carbapenams
Neurological toxicity and seizures
When are carbapenams most likely to cause neurological side effects and seizures
When prescribed to patients with renal impairment
What are 3 relative CI to cephalosporin and carbapenam use
- Renal impairment
- Epilepsy
- Risk of C.difficle infection
What is an absolute CI to cephalosporin and carbapenam use
Anaphylaxis to carbapenams, cephalosporins or penicillin
What drug may cephalosporins enhance the effect of and why
warfarin - due to destroying normal flora of the gut that produce vitamin K
What drug may cephalosporins increase toxicity of
increase renal toxicity of ahminoglycosides
Who is allowed to prescribe cephalosporins and why
microbiologists - due to risks of c.difficile
Explain the MOA of bisphosphonates
similar structure to pyrophosphate and therefore are incorporated into bone. When in bone, taken up into osteoclasts, where they collect and stimulate apoptosis.
What is first-line bisphosphonate for osteoporosis
Aledronic acid
What are two common side effects of bisphosphonates
Oeseophagitis
Hypophosphataemia
What is a rare but serious side effect of bisphosphonates
Osteonecrosis of the jaw
When is osteonecrosis of the jaw most likely
High-dose IV infusion bisphosphonates
What is a rare side effect in patient’s on long-term bisphosphonates
Osteonecrosis of the jaw
What are 3 absolute CI of bisphosphonates
- Renal impairment
- Hypocalcaemia
- Upper GI disorders
What are 2 relative CI for bisphosphonates and why
- Smoker
- Poor dental hygiene
= due to risk of osteonecrosis
What substances may reduce effectiveness of bisphosphonates
As bisphosphonate binds calcium salts its absorption can be reduced by iron, anatacids and calcium salts (eg. milk)
What dose of aledronic acid is given for osteoporosis
70mg weekly
What bisphosphonate is offered for paget’s disease
IV pamidronate or oral Riserdronate
