Ambien And Ambien CR Splitting And Absorption Differences

Our pharmacist discusses the differences in absorption between Ambien and Ambien CR and whether or not they can be cut.


I've read the precaution against splitting a zolpidem CR tablet but I'd like clarification as to the reason. If I were to cut a 10 mg zolpidem tablet into 3 pieces, or a zolpidem CR 6.25mg pill in half, both would be about 3 mg. What's the difference in absorption rates and effects? Thank you.

Asked by Nick On Mar 18, 2019

Answered by
Medical Content Reviewed By PharmacistAnswers Staff

On Mar 21, 2019
Ambien Bottle Of Pills On Wooden Table

You are correct that you should not cut, split or chew Ambien CR (zolpidem controlled release). Doing so will destroy the controlled-release system of the pill, causing the entire dose to be released at once. This defeats the purpose of using Ambien CR!

Ambien Vs. Ambien CR

In regard to the difference between Ambien and Ambien CR, both contain zolpidem. However, Ambien is an immediate-release formulation (zolpidem is released all at once) while Ambien CR tablets have a controlled release mechanism.

Ambien Release

After taking Ambien (zolpidem), it is rapidly absorbed and peak concentrations in the blood are seen within 90 minutes. You will begin to feel the effects of the drug within 15-30 minutes and it generally lasts between 4 to 8 hours.

Ambien CR Release

Ambien CR tablets are two-layers and exhibit what is known as 'biphasic' absorption.

After taking a dose by mouth, one layer of the tablet dissolves quickly, providing an immediate-release dose of zolpidem (just like regular Ambien tablets).

The second layer of Ambien CR tablets dissolves more slowly, providing an extended-release dose of zolpidem, and is intended to maintain blood levels of the drug later into the night.

The overall purpose of Ambien CR is to not only help you fall asleep (from the immediate-release zolpidem dose) but also to stay asleep (from the extended-release) dose.

Cutting Ambien Tablets

As mentioned, you should not cut Ambien CR tablets. Doing so will destroy the controlled-release properties of the drug, and you will lose its intended benefit of helping you not only fall asleep but stay asleep.

Regular Ambien tablets (the non-CR version) can safely be cut or split.

Answer Summary

Ambien (zolpidem) is an immediate-release tablet while Ambien CR has two layers, an immediate-release layer and an extended-release layer. Ambien tablets can be cut while Ambien CR tablets cannot be cut.


About the Pharmacist

Dr. Brian Staiger Pharm.D

Dr. Brian Staiger is a licensed pharmacist in New York State and the founder of He graduated from the University At Buffalo with a Doctor of Pharmacy degree in 2010. He has been featured in numerous publications including the Huffington Post as well as a variety of health and pharmacy-related blogs. Please feel free to reach out to him directly if you have any inquiries or want to connect! He's answered thousands of medication and pharmacy-related questions and he's ready to answer yours! Office: 716-389-3076

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