Adjusting Medications for Patients With Kidney Disease: Case Study

This case study examines factors contributing to significant adverse effects and hospitalization for a patient with chronic kidney disease who was ordered a non-renal-adjusted medication dose.

A patient with a history of renal failure requiring dialysis was seen for a painful rash by an urgent care physician. The physician diagnosed early-onset shingles. Although the physician noted that the patient was on dialysis, the full regular dose of valacyclovir (Valtrex)—1 gram to be taken three times a day—was ordered, with no reduction in the dosage to account for the patient’s renal failure. No laboratory tests were ordered, and no specialist was consulted regarding the drug dosing.

The patient took the valacyclovir prescription to the local pharmacy, where it was filled by pharmacy staff. The pharmacy computer system records did not contain any information about the patient’s medical history or allergies. In violation of the pharmacy’s policy, there was no documentation of any patient counseling by the pharmacist about this new medication. The patient took three valacyclovir pills that day, in accordance with the prescription.

Overnight, the patient developed an altered mental status, with delirium and confusion, and was brought to the emergency department. The patient was admitted to the hospital and diagnosed with valacyclovir toxicity. Restraints had to be placed due to the patient’s extreme agitation and combative behavior. The patient’s mental status improved significantly after dialysis.

Risk Management Discussion

Renal impairment affects the excretion of medications that are normally cleared by the kidneys. For patients with poor kidney function, failing to adjust medication dosages appropriately can lead to elevated medication levels and toxicity.

Experts were critical of the urgent care physician for failing to adjust the valacyclovir dose to account for the patient’s poor kidney function. Experts pointed out that appropriate dosing would have been 500 mg once per day, at most. The urgent care physician was criticized for not checking the patient’s creatinine clearance and for not speaking with a nephrologist prior to ordering the valacyclovir.

In addition, organizational policy required the pharmacist to counsel the patient about the new medication. The pharmacist was unable to produce documentation showing the patient had been counseled or that an effort had been made to obtain information about the patient’s significant medical history.

These failures led to the patient’s acute medication toxicity and hospitalization.

Patient Safety Strategies

The following strategies can help practitioners in ambulatory settings ensure that patients with renal insufficiency or renal failure receive appropriately adjusted medication doses:

• Have the patient complete a health history form at the first visit. Include specific questions on the form about kidney function. At subsequent visits, ask the patient to update the health history.
• Read the patient’s health history prior to prescribing or providing any medication. Be aware of the patient’s current medications, and be alert for potential medication contraindications or interactions.
• Ask the patient specifically about a history of any kidney issues if prescribing or providing a medication that is cleared renally. If the patient has any history related to kidney disease, check the creatinine clearance or glomerular filtration rate prior to prescribing the medication.
• Consult with a pharmacist or nephrologist for appropriate dose reductions, based on the patient’s level of kidney function.
• Pharmacists: Always counsel patients about new medication prescriptions. If the medication is cleared renally, ask the patient specifically about kidney history at the time of the pharmacy visit. Documentation of these interactions is vital.
• Always check with a pharmacist or a reputable online drug resource to verify if a particular medication requires renal dosing and the amount of any recommended dose adjustment. Although this list is not comprehensive, commonly used medications that may require renal dosing include many ACE inhibitors, beta blockers, hypoglycemic agents, analgesics, NSAIDs, many statins, many anti-infectives, some diuretics, and other medications including allopurinol, famotidine, gabapentin, omeprazole, metoclopramide, and some herbal medications.

For assistance in addressing any patient safety or risk management concerns, contact the Department of Patient Safety and Risk Management at (800) 421-2368 or by email.