What Medications Should You Hold Before Dialysis?

There is no universal list of medications that every dialysis patient should hold before a session, because the answer depends on the drug’s properties, the type of dialysis, and your individual medical situation. Blood pressure medications are the category most commonly discussed, and even there, blanket withholding is not supported by strong evidence. The real story is more drug-by-drug and patient-by-patient than most people expect, and getting the timing wrong in either direction can cause problems.

Blood Pressure Medications Are the Biggest Question

If you ask a room full of nephrologists whether to hold antihypertensives before hemodialysis, you will get a range of answers. The concern is straightforward: dialysis removes fluid from your blood, which lowers blood pressure on its own. If you also have a blood pressure medication on board, the combined effect can cause intradialytic hypotension, meaning your blood pressure drops dangerously low during the session. Symptoms range from dizziness and cramping to passing out, and severe episodes can damage the heart over time.

Current guidelines suggest giving blood pressure medications at night and holding them the morning of dialysis for patients who experience these drops. But a review of the available evidence concluded that withholding blood pressure medications before hemodialysis should not be routine practice, noting that more than half of dialysis patients already use some version of this approach despite limited data supporting it.¹ A cluster randomized trial that directly compared taking versus holding antihypertensives before dialysis could not demonstrate that taking them was safe enough to be considered equivalent for preventing intradialytic hypotension.² So the evidence is genuinely thin in both directions.

One underappreciated risk of routinely holding blood pressure medications is what happens between sessions. If you skip your morning dose every dialysis day, your blood pressure may run higher during the 44 or more hours between treatments. That interdialytic hypertension quietly raises cardiovascular risk, which is already the leading cause of death in dialysis patients.³ The decision really comes down to your individual pattern: if you regularly experience drops during treatment, holding certain medications may help; if your blood pressure runs high between sessions and you tolerate dialysis well, holding them could be doing more harm than good.

Not All Blood Pressure Drugs Behave the Same on Dialysis

One reason a blanket “hold all blood pressure meds” rule makes little sense is that different drug classes are removed by dialysis to very different degrees. Drugs that are highly dialyzable get pulled out of your blood during the session, which means their effect wears off whether you hold them or not. Drugs that are not dialyzable stay in your system throughout treatment, so taking them before a session has a more sustained blood-pressure-lowering effect.

ACE inhibitors are a mixed bag. Most of them are removed during dialysis, with enalapril and lisinopril being well-known examples that may need a supplementary dose after the session to maintain their effect. Fosinopril is the exception in this class and is not significantly removed.⁴ ARBs, by contrast, are generally not dialyzable, meaning their blood levels stay more stable throughout the session. This makes them a potentially better fit for patients who struggle with intradialytic blood pressure swings.

Among beta blockers, the distinction matters a lot. Atenolol is highly dialyzable and loses much of its effect during treatment, so giving it before dialysis may be largely pointless. Carvedilol and metoprolol are more fat-soluble and less affected. Calcium channel blockers like amlodipine are generally not removed by dialysis, providing relatively stable blood pressure control regardless of session timing.⁴ If you are on multiple blood pressure medications, your nephrologist may choose to hold one class while continuing another, based on how each drug interacts with the dialysis process.

Insulin and Diabetes Medications on Dialysis Days

Dialysis changes how your body handles blood sugar in ways that catch many patients off guard. Kidney failure itself slows insulin clearance, meaning insulin stays active in your body longer than it would with healthy kidneys. Dialysis sessions then add another wrinkle: the process can lower blood sugar further, especially when glucose-free dialysate is used. The result is that dialysis days carry a heightened risk of hypoglycemia.

One study of hospitalized hemodialysis patients with diabetes found that roughly 61% of all hypoglycemic episodes occurred in the 24 hours before a dialysis session, with risk climbing as total daily insulin doses increased.⁵ That pre-dialysis window is particularly vulnerable because the kidneys are not clearing insulin normally, so doses given the night before or that morning can stack up.

The most common recommendation is to reduce the basal insulin dose by up to 25% on hemodialysis days, though there is no firm consensus on the exact percentage.⁶ Some patients need even larger reductions. Oral diabetes medications like metformin are typically already discontinued by the time someone reaches dialysis due to the risk of lactic acidosis in severe kidney disease, so the main concern for most patients is insulin timing and dose. If you are on insulin and dialysis, frequent glucose monitoring on treatment days is essential.

Antibiotics and the Post-Dialysis Dosing Strategy

Antibiotics are one of the clearest examples of medications that should be timed around dialysis rather than simply held. Many commonly used antibiotics are removed by the dialysis machine to a meaningful degree, which means giving them before a session can leave you with subtherapeutic levels when the session ends, right when the drug is supposed to be fighting an infection.

The standard approach for drugs like vancomycin, cefazolin, and aminoglycosides is to administer them after the dialysis session. This avoids losing a large portion of the dose to the dialyzer and conveniently allows the drug to be given through the dialysis access, which eliminates the need for an extra IV stick.⁷ An expanding list of antibiotics beyond these traditional three is being studied for post-dialysis dosing, with the goal of achieving adequate drug exposure through the entire interdialytic period.

Aminoglycosides are a particularly interesting case. The traditional practice has been to give half the normal dose after dialysis, but there are clinical scenarios where dosing before or at the start of dialysis may actually be preferable. For infections requiring high peak drug concentrations, giving the aminoglycoside before dialysis lets levels spike while the drug is then cleared to safe trough levels by the session itself. In unstable patients or those with unreliable vascular access, though, post-dialysis dosing remains the safer approach.⁸

Pain Medications and Gabapentin

Gabapentin deserves its own mention because it is so widely prescribed for neuropathic pain in dialysis patients and because dialysis removes it aggressively. The drug is not bound to blood proteins and relies entirely on the kidneys for clearance, so in someone with no kidney function, gabapentin’s half-life stretches to roughly 132 hours, meaning a single dose lingers for days. During a hemodialysis session, about 35% of the drug is pulled out, and its half-life drops to around four hours.⁹

The practical implication is that gabapentin doses need to be small and infrequent on non-dialysis days to avoid toxic accumulation, and a supplemental dose is typically given after each session to replace what the dialyzer removed. Holding gabapentin before dialysis is less about preventing a problem during the session and more about the fact that, without dose adjustment, the drug builds up between treatments to the point where patients experience excessive sedation, dizziness, or confusion. After the session ends, drug levels can actually rebound upward by around 30% over the next couple of hours as gabapentin redistributes from tissues back into the blood.⁹

Anticoagulants in Dialysis Patients

Blood thinners require careful management around dialysis for a different reason than most drugs: dialysis patients already receive heparin during the session to prevent the blood from clotting in the circuit. Adding a systemic anticoagulant on top of that increases bleeding risk. Warfarin-treated hemodialysis patients experience major bleeding at roughly twice the rate of dialysis patients not on warfarin.¹⁰

For patients on direct oral anticoagulants like apixaban or rivaroxaban, the question of holding them arises mainly around procedures. European guidelines recommend stopping these drugs 36 to 48 hours before procedures depending on bleeding risk, though these recommendations were formally designed for patients with mildly to moderately impaired kidney function and deliberately exclude the most advanced kidney disease.¹¹ Bridging with heparin is generally not recommended for patients on these newer anticoagulants because their effect wears off predictably enough to simply time the last dose before a procedure.

For patients at high bleeding risk who still need dialysis, heparin-free protocols exist. Techniques like heparin-coated dialyzer membranes have been shown to reduce the odds of sessions ending prematurely due to circuit clotting while avoiding systemic anticoagulation entirely.¹²

Digoxin and Cardiac Drugs

Digoxin is a drug that commands extra caution in dialysis patients. It has a narrow therapeutic window, meaning the difference between an effective dose and a toxic one is small. Dialysis shifts electrolytes, particularly potassium, which directly affects how digoxin acts on the heart. A case report described a hemodialysis patient who presented with nausea, vomiting, and a heart rate of 30 beats per minute from digoxin toxicity, with an ECG showing complete heart block.¹³ The combination of fluctuating potassium levels during dialysis and the long half-life of digoxin in kidney failure makes toxicity a recurring danger. Digoxin itself is not efficiently removed by standard dialysis, so holding a dose will not significantly change what happens during the session, but close monitoring of levels and electrolytes is critical.

Phosphate Binders Should Not Be Held

Phosphate binders are one class of medication that you should absolutely continue taking on dialysis days, but the timing matters for a different reason than most drugs. These medications work by binding phosphorus in your food as it passes through your gut, preventing it from being absorbed into your bloodstream. They only work when they are taken with meals. Holding them before dialysis does not protect you from anything; it just lets more phosphorus into your blood.

Research has shown that taking phosphate binders with meals is substantially more effective than taking them before meals. In one study of aluminum hydroxide, taking it with food reduced serum phosphate by about 28%, compared to only 7% when it was taken 30 minutes before meals.¹⁴ The practical takeaway is that these pills belong with your food, every meal, every day, including dialysis days. A common problem is that patients use a fixed number of pills per meal regardless of how much phosphorus a given meal contains, which may contribute to the poor phosphate control seen in many dialysis patients.¹⁵ Ideally, you would adjust how many binders you take based on the phosphorus content of each individual meal.

Water-Soluble Vitamins After Dialysis

Dialysis strips water-soluble vitamins from your blood along with the waste products it is designed to remove. The losses can be substantial. One study measured vitamin washout during a single session and found that serum folate dropped by about 37%, a key form of vitamin B6 dropped by about 35%, and smaller losses occurred for thiamine and riboflavin.¹⁶ Losses of certain B vitamins can exceed what you take in from food: one analysis estimated dialysis-related losses of vitamin B2 at nearly double the recommended daily intake and vitamin B5 at about one and a half times.¹⁷

Because dialysis removes these vitamins so effectively, taking water-soluble vitamin supplements before a session is largely a waste. The standard practice is to take them after dialysis. Pyridoxine (vitamin B6) deficiency is especially common, with one study finding that over 80% of unsupplemented dialysis patients were severely deficient. Supplementing with at least 15 to 20 mg per day of pyridoxine after dialysis corrected this. For folic acid and vitamin C, lower doses than what many dialysis centers prescribe were found to be sufficient.¹⁸ Vitamin B12, which is bound to large proteins and not significantly removed by dialysis, did not require routine supplementation.

Psychiatric Medications Are Mostly Safe to Continue

Most psychiatric medications, including antidepressants, antipsychotics, and anti-anxiety drugs, are fat-soluble, heavily protein-bound, and metabolized by the liver rather than the kidneys. These properties make them poor candidates for removal by dialysis. As a result, the majority of psychotropic medications do not need to be held before dialysis sessions and can be used safely in the dialysis population. Lithium is the major exception: it is water-soluble, not protein-bound, and cleared almost entirely by the kidneys, which means dialysis removes it efficiently and dose timing matters.

Over-the-Counter Products and Herbal Supplements

One area where dialysis patients often run into trouble without realizing it is over-the-counter medications and herbal supplements. A study of patients with moderate to severe chronic kidney disease found that 47% of the over-the-counter products and natural products they were using were either contraindicated or should have been used with caution.¹⁹ Common culprits include NSAIDs like ibuprofen, which can worsen any residual kidney function and raise blood pressure, and magnesium- or aluminum-containing antacids, which can accumulate to dangerous levels.

Herbal supplements carry additional risks because they are not regulated like prescription drugs. Independent lab analyses have found supplements contaminated with heavy metals, pesticides, and undisclosed conventional drugs. In kidney disease, the risks are amplified by unpredictable drug metabolism, potential interactions with prescribed medications, and the ability of certain supplements to worsen electrolyte imbalances that are already a concern in dialysis.²⁰ The safest approach is to run every supplement and over-the-counter product past your nephrologist or pharmacist before taking it, since what seems harmless to someone with normal kidney function may be genuinely dangerous in your situation.

How the Type of Dialyzer Affects What Gets Removed

The medications removed during dialysis depend not just on the drug itself but on what kind of dialyzer membrane is being used. Newer medium cut-off membranes can clear larger molecules more efficiently than older high-flux designs. In a case of severe vancomycin toxicity, a medium cut-off dialyzer achieved a higher drug elimination rate and shorter plasma half-life than a standard high-flux membrane.²¹ High-flux membranes themselves clear drugs like cefazolin significantly faster than older high-efficiency membranes, with one study finding dialytic clearance rates nearly 70% higher with high-flux filters.²²

This matters practically because a dose recommendation developed for one membrane type may leave you under-dosed or over-dosed on another. Drug dosing protocols at your dialysis center should reflect the specific equipment being used, and if your center upgrades its dialyzers, medication doses may need to be revisited. Similarly, patients receiving continuous renal replacement therapy in an ICU setting face entirely different drug clearance dynamics than those on standard intermittent hemodialysis, requiring distinct dosing protocols.

Why Predicting Drug Removal Is Harder Than It Sounds

You might assume that pharmacists can simply look at a drug’s properties and predict whether dialysis will remove it. In reality, the relationship between a drug’s characteristics and its dialyzability is surprisingly weak. A study of 89 drugs found that protein binding, volume of distribution, and molecular weight together explained only about 27% of the variation in how much of a drug dialysis removes.²³ Protein binding was the strongest predictor, but even it accounted for only 17% of the variance. That means for any individual drug, you cannot reliably predict from first principles how much will be cleared. Real-world dialyzability data from clinical studies remains the gold standard for dosing decisions.

This unpredictability is a key reason why medication reviews by pharmacists familiar with dialysis are so valuable. One study of pre-dialysis and dialysis patients found medication discrepancies in 80% of patients reviewed, with pharmacists identifying hundreds of issues related to drug or dose selection. The majority of their recommended changes were accepted by the treating nephrologist.¹ If your dialysis unit offers a pharmacist review, take advantage of it. The interplay between your medications, your dialysis prescription, and your body’s residual kidney function creates enough complexity that even experienced clinicians benefit from a second set of eyes.