What medications affect GFR levels?
Medication Safety Issues with Newly Authorized PAXLOVID
On December 22, 2021, the US Food and Drug Administration (FDA) issued an Emergency Use Authorization (EUA) for PAXLOVID, consisting of oral tablets of nirmatrelvir that are co-packaged with oral tablets of ritonavir (an FDA-approved antiretroviral agent).
Emergency use of Paxlovid is indicated for the treatment of mild-to-moderate coronavirus disease 2019 (COVID-19) in adults and pediatric patients (12 years of age and older weighing at least 40 kg) with positive results of direct severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral testing, and who are at high risk for progression to severe COVID-19, including hospitalization or death. Paxlovid is not authorized for the treatment of hospitalized patients, or for use as pre- or post-exposure prophylaxis for prevention of COVID-19. Paxlovid is not indicated for use longer than 5 consecutive days.
Nirmatrelvir is available in 150 mg tablets, while ritonavir is a 100 mg tablet. For patients with normal renal function or mild renal impairment, the recommended dose is 300 mg of nirmatrelvir (two tablets) and 100 mg of ritonavir (one tablet), taken together, twice daily, in the morning and evening, for 5 days.
A dose reduction is necessary for patients with moderate renal impairment, defined as having an estimated glomerular filtration rate (eGFR) below 60 mL/minute, but more than or equal to 30 mL/minute. If patients have moderate renal impairment, they must only receive 150 mg of nirmatrelvir (one tablet) along with 100 mg of ritonavir, taken together, twice daily, in the morning and evening. Patients with severe renal impairment, with an eGFR below 30 mL/minute, should not receive the drug, as the appropriate dosage for patients with severe renal impairment has not been determined.
Important Note for Dispensing Pharmacists
Paxlovid is only available in a carton holding five blister cards, each containing the daily morning and evening doses (two nirmatrelvir tablets and one ritonavir tablet for each dose) for patients with normal renal function or mild renal impairment. For patients with moderate renal
impairment, the EUA directs pharmacists to remove one of the nirmatrelvir tablets for both the morning and evening doses from each blister card before dispensing Paxlovid to facilitate proper dosing (Figure 1). After removing one nirmatrelvir tablet from the morning dose and one from the evening dose on each blister card, the empty blisters on all five cards should be covered with manufacturer-supplied stickers (Figure 2). Pharmacies needing additional stickers should contact: [email protected] . It is essential for pharmacists to take these steps, as outlined in the EUA dispensing information for patients with moderate renal impairment.
Safety Concerns and Recommendations
Challenges with prescribing the dose. The prescriber may not be aware that the dose should be reduced for moderate renal impairment or that the drug should not be prescribed for patients with severe renal impairment. Thus, electronic prescribing systems should alert the prescriber to renal dosing requirements. Also, choosing the correct dose for patients with moderate renal impairment may require prescribers to manually enter the reduced dose in a text field. It is critical for prescriptions to specify the numeric dose of each active ingredient in Paxlovid as follows:
- 150 mg of nirmatrelvir with 100 mg of ritonavir for patients with moderate renal impairment
- 300 mg of nirmatrelvir with 100 mg of ritonavir for patients with normal renal function or mild renal impairment
Failure to remove tablets and cover empty blisters. One significant safety concern is that pharmacy staff may fail to remove one of the nirmatrelvir tablets from each dose of the blister card for all five days of therapy, and/or may miss applying the stickers to make patients aware that the packaging has been altered to remove unneeded tablets. Both of these steps are a requirement under the EUA, and pharmacies handling Paxlovid must ensure their pharmacists and pharmacy technicians address this issue and have a process in place to meet this requirement.
Failure to take the tablets together. Patients will be self-administering Paxlovid at home. Thus, it is extremely important for pharmacists to counsel patients to take both the nirmatrelvir and ritonavir tablets together in the morning and evening. For patients with moderate renal impairment, pharmacists should also explain that the packaging has been altered to provide the proper dose.
Paxlovid (nirmatrelvir co-packaged with ritonavir) is an inhibitor of CYP3A, the most abundant clinically significant group of cytochrome P450 isoenzymes, which may increase plasma concentrations of drugs that are primarily metabolized by CYP3A. At the same time, nirmatrelvir and ritonavir are CYP3A substrates; therefore, drugs that induce CYP3A may decrease nirmatrelvir and ritonavir plasma concentrations and reduce the therapeutic effect of Paxlovid. For complete information and a list of serious drug interactions and expected effects, please refer to the Paxlovid Fact Sheet for Healthcare Providers .
Providers must report all serious adverse events or medication errors potentially related to Paxlovid to the FDA MedWatch reporting program , which is mandatory for medications available under an EUA. Please also fax a copy of the MedWatch form to Pfizer (8666358337). ISMP also asks providers to report errors to the ISMP National Medication Errors Reporting Program (ISMP MERP) .
The Institute for Safe Medication Practices (ISMP) is an independent, nonprofit agency dedicated to medication safety. ISMP accepts no advertising in its publications or other work product. ISMP is an affiliate of ECRI, an independent, nonprofit organization improving the safety, quality, and cost‐effectiveness of care across all healthcare settings worldwide. Visit ISMP and ECRI .
Can Farxiga cause kidney damage?
Medically reviewed by Philip Thornton, DipPharm. Last updated on April 25, 2023.
Farxiga may cause acute kidney injury
Signs to watch out for include urinating less or swelling in you legs or feet
Before starting Farxiga your doctor will determine if you are at increased risk for acute kidney injury
Sodium-glucose cotransporter 2 (SGLT2) inhibitors, including Farxiga (dapagliflozin), may cause acute kidney injury (AKI), according to the results of postmarketing studies. Farxiga’s product label and Medication Guide provide warnings about the risk of kidney injury.
Some of the patients who developed AKI while taking a SGLT2 inhibitor, which are also known as gliflozins, required hospitalization and dialysis. At the time the initial post-marketing studies were done, Farxiga had only been approved for use in patients with type-2 diabetes mellitus so all the cases of AKI were reported in such patients. Farxiga was subsequently approved for the treatment of heart failure in May 2020 and chronic kidney disease (CKD) in April 2021.
What is acute kidney injury?
AKI is a sudden episode of kidney failure or damage. It has a rapid onset over the course of a few hours or days and results in the build-up of waste products in the blood. It also makes it difficult for the kidneys to regulate the level of fluid in the body.
What are the signs and symptoms of acute kidney injury?
In some cases patients may not have obvious signs or symptoms of AKI. However, signs and symptoms that do suggest AKI include:
- Decreased urine output
- Swelling in the legs or feet
- Shortness of breath
- Muscle twitching or cramps
- Itchy skin
- Chest pain or pressure
- Seizures or coma in severe cases
But isn’t Farxiga used to treat chronic kidney disease?
In April 2021, the US Food and Drug Administration (FDA) approved Farxiga to reduce the risk of kidney function decline, kidney failure, cardiovascular death and hospitalization for heart failure in adults with CKD who are at risk of disease progression.
A large phase III trial called DAPA-CKD, which was conducted in patients with or without diabetes who had CKD stages 2-4, found that treatment with Farxiga was beneficial in this group of patients and prolonged survival. Patients with stage 2 kidney disease have a mild form of kidney disease, while those with stage 4 disease have moderate to severe damage to their kidneys.
Despite being approved for use in certain patients with CKD, Fargixa is not recommended for the treatment of type 2 diabetes in patients with a estimated glomerular filtration rate (eGFR) of less than 45 ml/min/1.73m 2 , which indicates stage 3 kidney disease.
Before prescribing Farxiga, doctors will also consider factors such as whether you have congestive heart failure, decreased blood volume, or take medications such as a diuretic, angiotensin-converting enzyme (ACE) inhibitor, angiotensin receptor blocker (ARB) or nonsteroidal anti-inflammatory drug (NSAID), which may put you at greater risk of developing AKI while taking Farxiga.
- Food and Drug Administration (FDA). FDA Drug Safety Communication: FDA strengthens kidney warnings for diabetes medicines canagliflozin (Invokana, Invokamet) and dapagliflozin (Farxiga, Xigduo XR). June 14, 2016. [Accessed May 14, 2020]. Available online at: https://www.fda.gov/drugs/drug-safety-and-availability/fda-drug-safety-communication-fda-strengthens-kidney-warnings-diabetes-medicines-canagliflozin.
- National Kidney Foundation. Acute Kidney Injury (AKI). [Accessed May 14, 2020]. Available online at: https://www.kidney.org/atoz/content/AcuteKidneyInjury.
- Food and Drug Administration (FDA). Farxiga. Highlights of Prescribing Information. [Accessed May 5, 2021]. Available online at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2021/202293s024lbl.pdf.
- Diabetes.co.uk. SGLT2 Inhibitors (Gliflozins). January 15, 2019. [Accessed May 14, 2020]. Available online at: https://www.diabetes.co.uk/diabetes-medication/sglt2-inhibitors.html.
- Heerspink HJL, Stefánsson BV, Correa-Rotter R, et al. Dapagliflozin in Patients with Chronic Kidney Disease. N Engl J Med. 2020;383(15):1436-1446. doi:10.1056/NEJMoa2024816.
- American Kidney Fund. Stages of Chronic Kidney Disease (CKD). September 29, 2020. [Accessed January 26, 2021]. Available from: https://www.kidneyfund.org/kidney-disease/chronic-kidney-disease-ckd/stages-of-chronic-kidney-disease/.
- Food and Drug Administration (FDA). FDA Approves Treatment for Chronic Kidney Disease. April 30, 2021. [Accessed May 4, 2021]. Available from: https://www.fda.gov/news-events/press-announcements/fda-approves-treatment-chronic-kidney-disease.
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5 Drugs You May Need to Avoid or Adjust if You Have Kidney Disease
Medications save and improve lives, but it can be easy to overlook their risks and side effects, especially if you don’t think they apply to you. Twenty-six million Americans have chronic kidney disease and most don’t know it.
If you don’t know how well your kidneys are working, you may not realize that certain medications could be damaging your kidneys and other parts of your body. Both prescription and over-the-counter medications are filtered by the kidneys. This means that your kidneys degrade and remove medications from the body.
When your kidneys aren’t working properly, medications can build up and cause you harm. It’s important to get your kidneys checked and to work with your doctor to make any adjustments to your medication regimen, such as dosing changes or substitutions. This will help prevent any negative effects from the medication, including further kidney damage.
You can determine your level of kidney function with a blood test for serum creatinine to calculate an eGFR measurement. An eGFR estimates how well your kidneys are filtering wastes from the blood.
The National Kidney Foundation encourages you to learn more about the health of your kidneys in order to protect these vital organs when taking medications. Always speak with your clinician and pharmacist to determine whether the medications that you’re taking should be adjusted based on your kidney function. Only make changes to your prescription medications with the supervision of your trained medical practitioner. Ask questions and evaluate the risks and benefits based on your specific health needs.
Here are 5 common types of prescription and over-the-counter medications may need to be adjusted or replaced if you have kidney damage.
- Cholesterol medications. The dosing of certain cholesterol medications, known as «statins», may need to be adjusted if you have chronic kidney disease.
- Pain medications. If you have decreased kidney function some over-the-counter and prescription pain medications, including nonsteroidal anti-inflammatory drugs (NSAIDs), are not recommended because they can reduce blood flow to the kidneys. Certain narcotic pain medications can build up in the body and cause serious problems for patients with chronic kidney disease.
- Anti-microbial meds. Many anti-fungal, antibiotic and antiviral medications are cleared by the kidneys. It’s important that you and your clinician are aware of your level of kidney function so that a kidney-safe medication can be prescribed for your treatment.
- Diabetes medications. Insulin and certain medications used by people with diabetes are cleared by the kidneys. Because diabetes is a leading cause of kidney disease, it’s important that those with diabetes control their blood sugar levels. Blood sugar control typically involves a combination of diet, physical activity, and medication. If you have diabetes and chronic kidney disease, check with your physician to see if any dosing changes need to be made based on your level of kidney function.
- Upset stomach/antacid medications. This group of over-the-counter medications can disrupt the body’s electrolyte balance if you have chronic kidney disease. Check with your doctor to see if these are safe for you to use.
For more information about medications that may need to be adjusted or avoided if you have chronic kidney disease, click here.