Can patients take their medications before dialysis?

Medication Timing in Dialysis Patients

Medications should generally be administered AFTER dialysis sessions, not before, to prevent premature drug removal and ensure therapeutic efficacy. 1, 2, 3

General Principle for Medication Timing

The fundamental rule is straightforward: give once-daily medications after dialysis completion. 3 This approach serves multiple critical purposes:

• Prevents immediate drug removal during the dialysis session, which would result in subtherapeutic levels and treatment failure 2
• Facilitates directly observed therapy and ensures proper medication administration 2
• Maintains therapeutic drug concentrations throughout the interdialytic period 1

Medication-Specific Considerations

Dialyzable Medications

For drugs that are significantly removed by hemodialysis (such as pregabalin, cephalosporins, and many antibiotics):

• Always administer immediately after dialysis to avoid premature removal 1, 2
• Maintain the full dose amount but extend dosing intervals (e.g., three times weekly after each dialysis session) rather than reducing the milligram dose 2

Antihypertensive Medications - A Critical Exception

Antihypertensives should NOT be routinely withheld before dialysis. 4 This is a common pitfall in dialysis care:

• The widespread practice of holding antihypertensives predialysis is often inappropriate and can worsen interdialytic blood pressure control 4
• Withholding antihypertensives may increase the prevalence of intradialytic hypertension and cardiac arrhythmias 4
• Predialysis administration of antihypertensives is appropriate and necessary in many patients, with drug choice based on comorbidities, pharmacokinetics, and dialyzability 4

The concern about intradialytic hypotension should not automatically lead to withholding all antihypertensives, as this practice may actually worsen overall blood pressure control and cardiovascular outcomes 4.

Practical Implementation Algorithm

For most medications:

1. Schedule administration immediately after dialysis completion 1, 2, 3
2. Adjust dosing intervals (typically to three times weekly) rather than reducing doses 2
3. Consider serum drug concentration monitoring for narrow therapeutic index drugs 1, 2

For antihypertensives specifically:

1. Assess individual patient's blood pressure patterns (predialysis, intradialytic, postdialysis, interdialytic) 4
2. Continue predialysis antihypertensives unless specific intradialytic hypotension episodes occur 4
3. Select agents based on dialyzability and pharmacokinetics if timing adjustments are needed 4, 5

Critical Safety Considerations

Common pitfalls to avoid:

• Never administer dialyzable medications before dialysis, as this results in immediate drug removal and treatment failure 2
• Do not routinely withhold all antihypertensives predialysis based solely on theoretical concerns about hypotension 4
• Avoid reducing milligram doses of concentration-dependent drugs (like antibiotics), as adequate peak levels are required for efficacy 2

Monitoring requirements:

• Watch for signs of drug toxicity when initiating therapy or adjusting doses, particularly with CNS depressants (opiates, gabapentin, benzodiazepines) that can cause falls and altered mental status during dialysis 6
• Consider therapeutic drug monitoring for medications with narrow therapeutic indices 1, 2
• Monitor for intradialytic adverse events including hypotension, bleeding (with antithrombotics), and hypoglycemia (with sulfonylureas) 6

Peritoneal Dialysis Patients

For patients on peritoneal dialysis, the approach differs slightly:

• Drug removal is substantially lower than hemodialysis, so supplemental dosing after exchanges is generally not necessary 7
• Dosing can follow guidelines for pre-dialysis chronic kidney disease patients 7
• Weekly dosage requirements are similar between peritoneal dialysis and hemodialysis patients 7