Some antibiotics are not safe for people with renal failure. When prescribing certain antibiotics, doctors may adjust the dose or frequency to protect the kidneys.

Renal failure occurs when the kidneys cannot effectively eliminate waste. This leads to waste products accumulating in the bloodstream.

Infections are common in people with renal failure, and doctors must choose safe and effective antibiotics to treat these infections.

When doctors prescribe antibiotics that are unsafe for people with renal failure or prescribe inappropriate doses, side effects may occur.

This article lists which antibiotics are safe in renal failure and explains what factors a doctor must consider before safely prescribing them.

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Not all antibiotics are unsafe for people with renal failure. Depending on the severity of kidney disease and the infection that needs treatment, different options are available.

Doctors must evaluate the severity of renal failure before prescribing any medication. To do so, they calculate a person’s glomerular filtration rate (GFR). A low GFR means that the kidneys cannot effectively eliminate certain waste products or substances from the blood.

Antibiotics that do not depend on kidney filtration are most appropriate for people with renal failure. The following drugs are safe for people with renal failure:

  • ceftriaxone (Rocephin)
  • clindamycin (Cleocin)
  • doxycycline (Acticlate)
  • moxifloxacin (Avelox)
  • azithromycin (Zithromax)

This non-exhaustive list of safe antibiotics leaves very few options for doctors. While other antibiotics may be unsafe, different prescribing strategies can provide additional options for treating infections. For example, a doctor can adjust the dose and/or frequency.

People living with chronic kidney failure are at risk of accumulating high concentrations of antibiotics in their bloodstream. To prevent this, doctors will avoid prescribing certain antibiotics.

Aminoglycosides are a class of antibiotics that cause kidney injury and can worsen kidney failure. Some examples of antibiotics in this drug class are tobramycin (Tobrex) and gentamycin (Garamycin).

While amikacin (Amikin) is also an aminoglycoside, doctors may still prescribe it to people with kidney failure but make certain adjustments.

Doctors can safely prescribe an antibiotic to people with renal failure by making some cautionary changes, such as using lower doses and less frequent doses. The decision to prescribe an antibiotic that can potentially worsen kidney function is based on the following factors:

  • the severity of a person’s condition
  • the infection
  • possible side effects of the medication

When prescribing potentially unsafe antibiotics for people with renal failure, doctors may need to follow up and monitor them for signs and symptoms of worsening kidney function.

Many medications, including antibiotics, can be safe for people with renal failure if doctors adjust the dosage. Understanding how the antibiotic acts in the body can help determine the most appropriate and safe dosing.

When doctors adjust dosage, they will change either the timing of each dose or the amount of medication a person takes each time.

Reducing doses

To adjust the dosage of beta-lactam antibiotics, doctors will lower the amount of medication a person takes at each dose. The time interval between doses will remain the same.

Examples of beta-lactam antibiotics are penicillins, cephalosporins, and carbapenems.

Macrolides, such as clarithromycin (Biaxin) and erythromycin (Erythrocin), are safe, but only in certain adjusted doses. For example, doctors reduce the dose of clarithromycin to 50% of the usual dose in people with severe renal failure.

Interval doses

To adjust the dosage of certain drugs, doctors will keep the dose the same but lengthen the interval between doses. For example, if a person typically takes a dose every 12 hours, the doctor can lengthen the interval to every 24 hours.

Interval dosing may be beneficial when prescribing fluoroquinolones to people with renal failure.

Fluoroquinolones are a group of antibiotics that includes:

  • ciprofloxacin (Cipro)
  • levofloxacin (Levaquin)
  • ofloxacin (Ocuflox)
  • delafloxacin (Baxdela)

What about a person undergoing hemodialysis?

Dosing also matters if people with renal failure are undergoing hemodialysis — a procedure that filters the blood, removing any accumulated substances and drugs.

For example, doctors may choose to administer certain intravenous antibiotics, such as cefazolin (Ancef), after a dialysis session.

Depending on the type of antibiotic a person with renal failure is using, they may experience different side effects. With unadjusted doses of beta-lactam antibiotics, people may experience:

  • confusion
  • seizures
  • uncontrollable twitching or jerking of a muscle group

When fluoroquinolone antibiotics accumulate in the bloodstream, people may experience:

  • ruptured tendons
  • tingling, numbness, or pain in the fingertips and toes
  • mental health side effects

Aminoglycosides can cause side effects that affect the ear, such as:

  • balance issues
  • problems with coordination
  • impaired hearing

Sometimes combining two antibiotics, such as piperacillin-tazobactam (Zosyn) and vancomycin (Firvanq), causes drug interactions in people with renal failure. These drug interactions further damage the kidneys.

Antibiotics are not the only drugs that require specific attention in people with renal failure. Many different drugs pass through the kidneys and can accumulate if a person has renal failure.

Renal disease may change the concentration and effect of a drug in the body, which can affect a person’s response to it. For example, higher drug concentrations can lead to more side effects.

Certain medical conditions can further complicate prescribing of antibiotics and other drugs for people with renal failure. Doctors consider the following factors:

  • avoidance of nephrotoxic drugs, such as NSAIDs and aminoglycosides, when possible
  • whether the person is a smoker
  • whether the person has other conditions, such as:
    • unmanaged diabetes
    • dehydration
    • hypertension
    • high levels of lipids, or fats (hyperlipidemia)
    • high levels of phosphates (hyperphosphatemia)

If there is an underlying issue, doctors should resolve or account for it before prescribing any new medications.

Renal failure can have different effects on drugs but will often lead to accumulations and possible toxicities.

Infections are common in people with renal failure. Some antibiotics are contraindicated in some people with renal failure. Most antibiotics require dose or frequency adjustments for people with renal failure.

Doctors will prescribe medications on an individual basis. This depends on many factors, including the severity of the renal disease, the specific infection, any underlying conditions a person has, and the potential side effects of the medication.

People can still experience side effects with certain antibiotics, so talking with a doctor about any concerns may be beneficial.