Difference Between Zolpidem and Zolpidem Tartrate


The basic differences between Zolpidem and Zolpidem tartrate are where the drugs can be acquired legally, the length of time the drugs are active in producing sleep, and the trade names that the drugs are called in different countries. The action, warnings, potential for abuse, and side effects of Zolpidem and Zolpidem tartrate are basically the same.

The patents and distribution rights for Zolpidem are owned by the French pharmaceutical manufacturer Sanofi-Aventis. The company had exclusive rights to sell this sleep aid in the United States until 2007 when the United States Food and Drug administration approved generic versions of Zolpidem that were Zolpidem tartrate.

The short and simple chemical change is adding tartaric acid to one site in the Zolpidem molecule while losing an atom of hydrogen. The change in structure is sufficient to produce a new chemical that is considered a different drug than Zolpidem.

The change in Zolpidem in the United States was not just money motivated but naturally money was one reason. The addition of the tartrate radical to the Zolpidem produced a time released version of the drug. Tests in the United States and in Europe have shown that Zolpidem tartrate can maintain sleep for a long period of time while Zolpidem can only be proven to initiate sleep but not maintain sleep.

The reason that Zolpidem tartrate promotes longer periods of sleep than Zolpidem involves a drug’s half-life. The half-life of a drug is the amount of time that one half of the active ingredient in the drug is used or converted to an inactive form in the body. Zolpidem has a half-life of between three and four hours depending on how much the person that takes the drug weighs. The half-life of Zolpidem tartrate is two to three times longer because of the difference in chemical structure.

The trade name for Zolpidem that is most commonly known in the United States is Ambien. A time released version that is Zolpidem tartrate is called Ambien CR. The CR stands for controlled release. Ambien has become one of the most frequently used prescription sleep aids in the world.

Besides the difference in initiating sleep and promoting periods of continued sleep the two drugs have the same method of action. The drugs act on the same receptors in the brain that benzodiazepines do. Zolpidem and Zolpidem tartrate start working to promote sleep in 15 minutes on average.

Both drugs can cause a person to be too drowsy or “hung over” to operate a car or dangerous machinery the day after taking the drug for sleep.

The United States Food and Drug Administration recommended that the dosage for men and women for both drugs be halved due to the high level of accidents related to the side effects of the two drugs. The most recent research indicates the side effects are more pronounced in men than women despite the differences in weight.

Zolpidem and Zolpidem tartrate are basically two versions of the same drug. One lets you go to sleep and one helps you stay asleep longer.