Can I Take Medications Before a Fasting Blood Test?

Can I Take Medications Before a Fasting Blood Test – Overview

If your healthcare provider has advised you to undergo a fasting blood test, you must avoid eating or drinking anything (except water) for several hours before the test.

Normally, food and beverages are absorbed into your bloodstream when you eat and drink. This may affect the results of certain types of blood tests.

When Is Fasting Required Before a Blood Test

The most commonly performed blood tests that need you to fast are:

Glucose Test

The glucose test is used to measure blood sugar levels. A fasting glucose test requires you to fast for at least 8 hours. A glucose tolerance test, used for diagnosing diabetes, begins with a fasting blood sample, followed by drinking a glucose-rich beverage, with subsequent blood samples taken over a few hours to measure the body’s response to glucose.

Glucose tests are important in diagnosing diabetes.

Lipid Test

Lipid tests measure the levels of various fats in the blood, including triglycerides, LDL cholesterol, HDL cholesterol, and total cholesterol. These tests help assess the risk of heart disease.

How Long Do You Need to Fast Before a Fasting Blood Test

Doctors usually advise patients to fast for at least 8 to 12 hours before a test. Most tests that require fasting are normally scheduled for the morning, so most of the fasting time is overnight.

What Can You Drink Besides Water Before a Fasting Blood Test

It’s recommended to only drink water before a fasting blood test. Drinking other beverages like coffee, soda, or juice can affect the results of certain tests. Water does not affect the outcomes and can help make drawing blood easier

However, drinking water is acceptable before a fasting blood test, and doctors advise it. Water helps to add more fluid to your bloodstream, making it easier to draw blood for the test.

Can I Take Medication Before a Fasting Blood Test

You will need to consult with your healthcare provider regarding this. It’s important to consult your healthcare provider about taking medications before a fasting blood test. While many medications may not affect fasting lab tests, some can interfere with results and must be paused or taken cautiously.

What if You Mistakenly Eat or Drink Anything Before a Fasting Blood Test

If this happens, make sure to tell your healthcare provider. Usually, your healthcare provider will reschedule the fasting blood test for later when you can complete your fast.

When Can I Eat and Drink After a Fasting Blood Test

Once your test is complete, you can eat and drink normally. You may want to bring a snack so you don’t need to stay hungry for long once the blood test is completed.


Discuss every query or doubt with your healthcare provider before scheduling the fasting blood test. You should consult your healthcare provider before taking any lab test. While many tests do not require fasting, certain specific tests do. Following your healthcare provider’s instructions regarding fasting and any other preparations is crucial to ensure accurate test results.

For others, you may be advised to avoid certain foods or drinks, medications, and even activities. You are taking the right precautions before a blood test, ensuring an accurate result and the best diagnosis.

See Also

What is the Most Popular Medication for High Blood Pressure

What Medications Disqualify You From Donating Blood

Integrative Medicine Training for Physicians

How to Educate Patients About Medications

Do Blood Thinners Decrease Blood Pressure

Current Version
December 17, 2022
Updated By
Franco Cuevas, MD
October 30, 2022
Written By
Shubham Grover
March 17, 2024
Updated By
Franco Cuevas, MD

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