CT Scan with Non-Ionic Contrast: Diabetes and Medication Considerations

Q: CT Scan with Non-Ionic Contrast: Diabetes and Medication Considerations

Hello! Here are the answers to your questions： <br>Question 1： The medication that needs to be discontinued is "Metformin HCl 850mg." The discontinuation period is the day of the CT scan and the two days before and after, totaling five days. <br>For example, if the CT scan is sch

Non-ionic contrast agent for brain CT (computed tomography)?

CT scan of the brain: I have had diabetes for 8 years, and my recent blood tests show normal kidney function.
Below are the medications I am taking:
Metabolism specialist: Metformin HCl 850 mg, Lyrica (pregabalin) 75 mg * 2 tablets.

Psychiatrist: At bedtime: Zoloft (sertraline) 50 mg * 2 tablets, Mirtazapine 50 mg * 2 tablets, Seroquel (quetiapine) 50 mg * 1 tablet, Zolpidem 10 mg * 2 tablets, Flunitrazepam 2 mg * 2 tablets, Alprazolam 0.5 mg * 2 tablets at night.

ENT specialist: Loratadine 10 mg.

Urology specialist: Tamsulosin 0.2 mg * 2 tablets, Baclofen 5 mg once in the morning and evening, Bethanechol chloride 25 mg three times a day.

Cardiology specialist: Somil S.C.
Tab - 40 mg, 60 mg.
Question 1: The doctor wants to perform a CT scan of my brain, but I am taking the medications listed above.
Which medications should I stop taking a day or a week before the procedure? After the procedure, how long should I wait before resuming them—one day or one week?
Question 2: Is there a possibility that the non-ionic contrast agent could cause chronic kidney failure after administration?
Question 3: The consent form from the hospital mentions that diabetic patients have a higher risk of kidney failure.
Does this refer to acute kidney failure or chronic kidney failure?
Thank you, doctor, for addressing these three questions.

NOGOOD, 30~39 year old female. Ask Date: 2020/09/22

Dr. Ye Qianyu reply Family Medicine

Hello! Here are the answers to your questions:
Question 1: The medication that needs to be discontinued is "Metformin HCl 850mg." The discontinuation period is the day of the CT scan and the two days before and after, totaling five days.
For example, if the CT scan is scheduled for 10/1, the discontinuation dates would be 9/29, 9/30, 10/1, 10/2, and 10/3.
Question 2: The contrast agent has nephrotoxic effects, and patients with impaired renal function, dehydration, and chronic diabetes are at a relatively higher risk of developing acute or severe renal failure.
It is advised that if there are no abnormalities in heart, lung, and kidney function, you should increase your fluid intake before and after the examination.
If you have concerns regarding the examination, it is recommended that you consult the physician who arranged the test.
Question 3: Both scenarios are possible.
Acute renal failure is defined as a sudden loss of kidney function due to an acute factor or illness, which typically can return to normal after treatment.
In contrast, when a certain cause leads to damage of kidney cells that prevents the effective removal of metabolic waste and excess fluid from the body, and if this condition is chronic and irreversible, it is referred to as chronic renal failure.

Reply Date: 2020/09/22

More Info

When considering a CT scan with non-ionic contrast for a patient with a history of diabetes and current medication use, there are several important factors to take into account.
1. Medication Management Before and After the CT Scan:
For patients taking Metformin (like yourself), recent guidelines suggest that it is generally safe to continue using Metformin if your kidney function is normal (eGFR ≥ 60 mL/min). However, it is often recommended to temporarily discontinue Metformin for 48 hours after receiving iodinated contrast material to prevent potential contrast-induced nephropathy, especially if there are any concerns about kidney function.
Regarding your other medications, most do not require cessation before a CT scan. However, medications that can affect kidney function or have sedative effects, such as Lyrica (pregabalin) and certain psychiatric medications, may need to be discussed with your healthcare provider. It is essential to consult with your physician regarding the specific timing for stopping and resuming these medications, as individual circumstances can vary.

2. Risk of Chronic Kidney Disease (CKD) from Non-Ionic Contrast:
The concern about non-ionic contrast agents leading to chronic kidney disease (CKD) is primarily related to acute kidney injury (AKI) rather than direct causation of chronic conditions. Non-ionic contrast agents are generally considered safer than ionic ones, especially in patients with normal renal function. However, in patients with diabetes, there is an increased risk of AKI, particularly if there are pre-existing renal issues. If your kidney function is currently normal, the risk of developing CKD from a single CT scan with non-ionic contrast is low, but it is crucial to monitor kidney function post-procedure.

3. Understanding the Risk of Kidney Failure in Diabetic Patients:
The consent form mentioning the increased risk of kidney failure in diabetic patients typically refers to acute kidney injury rather than chronic kidney disease. Diabetes can lead to diabetic nephropathy, which is a progressive condition that can result in CKD over time. However, the immediate concern with contrast use is the potential for AKI, particularly in patients with risk factors such as diabetes, dehydration, or existing kidney impairment.
In summary, before your CT scan, it is advisable to:
- Discuss with your healthcare provider about the timing for stopping and resuming Metformin and any other medications.

- Ensure that your kidney function is monitored after the procedure.

- Understand that while there is an increased risk of acute kidney injury with contrast use in diabetic patients, this does not necessarily lead to chronic kidney disease unless there are other underlying issues.

Always communicate openly with your healthcare team about your medications and any concerns you may have regarding the procedure. They can provide personalized recommendations based on your health status and medication regimen.

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