Many things can make it difficult to fall asleep or stay asleep here and there. But trouble falling asleep consistently is known as insomnia. Lunesta and Ambien are two commonly prescribed drugs for short-term use for insomnia. Lunesta is a brand name for eszopiclone. Ambien is a brand name for zolpidem.

Ambien and Lunesta decrease brain activity and produce a sense of calm. This can help you fall and stay asleep. Lunesta and Ambien are both intended for short-term use. However, they differ in their strengths and how long they work in your body.

Potential side effects:-
Common side effects of both drugs are lightheadedness and dizziness. You may also have continued sleepiness during the day. If you feel lightheaded or sleepy, don’t drive or use dangerous machinery. In 2013, the Food and Drug Administration (FDA) issued a safety announcement rushed.

Source for Ambien:- 
For some people, this drug caused lingering effects the morning after taking it. These effects impaired alertness. Both drugs have the potential for some rare but serious side effects, including:
- memory loss
- behavior changes, such as becoming more aggressive, less inhibited, or more detached than normal
- depression or worsening depression and suicidal thoughts confusion
- hallucinations (seeing or hearing things that aren’t real)
Both drugs carry the risk of dependence and withdrawal. If you take high doses of either one or use it for more than 10 days, you may develop a physical dependency. You’re at greater risk of developing a dependency if you’ve had substance misuse problems in the past. Stopping suddenly can lead to withdrawal symptoms. Symptoms of withdrawal include shakiness, nausea, and vomiting. To avoid withdrawal symptoms, speak to your doctor about reducing your dose a little at a time.