The status of some commonly used prescription medications to treat insomnia:

• Ambien: The United States’ current best-selling insomnia drug. Its maker, Sanofi-Aventis SA, is trying to hold onto the 11-year-old product’s $1.9-billion-a-year sales lead by introducing a new longer-acting formulation.

• Indiplon: A yet-to-be-brand-named drug being investigated in late-stage clinical trials by Neurocrine Biosciences and Pfizer.

• Lunesta: The only prescription sleep aid approved by the Food and Drug Administration for long-term use.

• Rozerem: A drug being investigated in late-stage trials by Takeda Pharmaceuticals that has yet to receive FDA marketing approval but has won FDA acceptance of its proposed brand name. Because it acts differently than other insomnia medications, it may have less potential for drug abuse.

• Sonata: Fast-acting medication sold in generic form under the name Zaleplon.

• Trazodone: Sedating anti-depressant that is not approved as an insomnia treatment but has long been prescribed for that use by psychiatrists, in part because the generic medication is inexpensive.

By The Associated Press