Ambien, having a drug name zolpidem is a member of the controlled hypnotics family. It is commonly prescribed to treat sleeplessness, i.e. insomnia. The drug is available in different forms and lets your doctor decide, which form is best suitable for you. Ambien has many side effects and a few of them are fatal. It may cause a severe allergic reaction, and if you experience any signs of such reaction after taking Ambien, seek medical help immediately. Ambien may cause hives, difficulty in breathing, swelling of lips, neck, tongue, or the entire face. Don’t share Ambien with another person, even if he/she has the same symptoms you have.