Hemodialysis vs Peritoneal Dialysis

Clinical Pharmacist Overview

Dialysis is a renal replacement therapy (RRT) used in patients with end-stage kidney disease (ESKD) or severe acute kidney failure to remove uremic toxins, excess fluid, and correct electrolyte and acid–base disturbances. The two main modalities are hemodialysis (HD) and peritoneal dialysis (PD), which differ significantly in technique, physiology, and medication management implications.

Hemodialysis (HD)

Definition

Hemodialysis removes solutes and excess fluid by circulating the patient’s blood through an external dialyzer (artificial kidney) across a semipermeable membrane.

Mechanism

• Diffusion: removal of urea, creatinine, potassium
• Ultrafiltration: fluid removal via pressure gradients
• Requires vascular access (AV fistula, graft, or central venous catheter)

Schedule & Setting

• Typically 3 times weekly, 3–5 hours/session
• Performed in dialysis centers or at home (less commonly)

Clinical Features

• Rapid solute and fluid shifts
• Intermittent therapy
• Higher risk of intradialytic hypotension

Pharmacist Clinical Considerations

• Drug removal depends on:
  • Molecular weight
  • Protein binding
  • Water solubility
  • Dialyzer membrane type
• Commonly dialyzable drugs:
  • Aminoglycosides, vancomycin, lithium
• Post-dialysis dosing often required
• Anticoagulation (heparin) commonly used during sessions
• Monitor for:
  • Hypotension
  • Electrolyte fluctuations (especially potassium)

Peritoneal Dialysis (PD)

Definition

Peritoneal dialysis uses the patient’s peritoneal membrane as the dialysis surface by instilling dialysis fluid into the abdominal cavity.

Mechanism

• Diffusion and osmosis occur across peritoneal capillaries
• Dialysate contains glucose or icodextrin as osmotic agents
• Requires peritoneal catheter

Types

• CAPD (Continuous Ambulatory PD): manual exchanges during the day
• APD (Automated PD): machine-assisted, usually overnight

Schedule & Setting

• Continuous therapy
• Performed at home, offering greater flexibility

Clinical Features

• More stable fluid and electrolyte control
• Preserves residual renal function longer
• Increased risk of peritonitis

Pharmacist Clinical Considerations

• Less abrupt drug clearance → more predictable drug levels
• Higher doses may be needed for some drugs due to continuous clearance
• Antibiotics may be given intraperitoneally (e.g., vancomycin, ceftazidime)
• Monitor for:
  • Hyperglycemia (glucose-based dialysate)
  • Weight gain and dyslipidemia
• Adjust insulin dosing in diabetic patients

Hemodialysis vs Peritoneal Dialysis (Comparison Table)

Pharmacotherapy Impact Summary

• HD:
  • Requires careful timing of drug administration
  • Frequent post-dialysis supplementation
  • Higher variability in serum drug levels
• PD:
  • Allows steadier drug exposure
  • Unique intraperitoneal drug administration option
  • Requires monitoring for metabolic complications