A 76 year-old man with end stage renal failure is on continuous ambulatory peritoneal dialysis (CAPD). His other co-morbidities include hypertension, type 2 diabetes mellitus, coronary artery disease, ischemic cardiomyopathy and gout. He is admitted with an episode of CAPD peritonitis. He is complaining of severe abdominal pain. You are the pharmacist and you are reviewing his inpatient medications. These include amlodipine, aspirin, insulin glargine, hydralazine, metoprolol, vildagdliptin, frusemide, darbopoetin (alfa), calcium carbonate. His usual peritoneal dialysis regime is 2.5% dextrose 2 litres two bags per day and icodextrin 7.5% 2 litres one bag a day.

He was started on cefazolin and gentamicin via intraperitoneal injections. 

a) What class of antibiotic is cefazolin? How is it excreted? Apart from intraperitoneal, via what other route(s) may the drug be administered? (3 marks)

b) What class of drug does gentamicin belong to? Name TWO concentration-dependent toxicities associated with gentamicin. (3 marks)

c) What is the main route of elimination of gentamicin? How should dosing of gentamicin be adjusted in patients with renal impairment? If the pre-dose (trough) gentamicin level is high, what would you advise on subsequent dosing? (4 marks)

d) What are the differences between icodextrin and dextrose peritoneal dialysis solutions? What are the potential benefits and drawbacks of icodextrin? (3 marks)

e) The patient was given a dose of IV morphine 10 mg and became drowsy with respiratory depression. What is the likely cause? Explain how morphine pharmacokinetics is altered in renal failure. (3 marks)

f) List TWO classes of glucose lowering drugs that can be safely used in end stage kidney disease. For each class of drug, explain whether dose reduction is required. (4 marks)