(Reuters) - U.S. state, federal and local authorities across the United States are struggling to contain a rising tide of prescription drug abuse, which federal data show is now the single-biggest cause for an increase in drug overdose deaths.

Here are some facts on prescription drug abuse in the United States.

* In the 45-54 age group, overdose deaths fuelled by prescription drugs now surpass motor vehicle deaths as the number one cause of accidental death. (Congressional testimony by Len Paulozzi, an epidemiologist with the National Centre for Injury Prevention and Control, on March 12).

* Nearly 7 million Americans abuse prescription drugs -- more than the abuse of cocaine, heroin, hallucinogens, Ecstasy and inhalants combined. That compares with 3.8 million in 2000, an 80 percent increase. (U.S. Department of Health and Human Services' National Survey on Drug Use and Health)

* Number of Americans going into treatment for abuse of painkillers rose 321 percent between 1995 and 2005. (White House Office of National Drug Control Policy).

* Total number of stimulant prescriptions in the United States soared from around 5 million in 1991 to nearly 35 million in 2007. Prescriptions for opiates -- hydrocodone and oxycodone products -- rose from around 40 million in 1991 to nearly 180 million in 2007. (Nora Volkow, Director of National Institute on Drug Abuse, March 12 congressional testimony)

* Drug-related emergency department visits that involved prescription opioids rose 153 percent from 1995 to 2002, from 42,857 to 108,320 (U.S. Department of Health and Human Services' Substance Abuse and Mental Health Services Administration)

* Deaths involving prescription opioid analgesics rose 160 percent in the 5 years from 1999 to 2004. By 2004, opioid painkiller abuse deaths outnumbered total deaths involving heroin and cocaine. (U.S. Department of Health and Human Services' Centers for Disease Control and Prevention)

* Illicit trade in prescription narcotics -- including fraudulent insurance claims for bogus prescriptions, treating phantom injuries and other illegal deceptions -- drain health insurers of up to $72.5 billion a year, including up to $24.9 billion annually for private insurers. (Coalition Against Insurance Fraud)

(Reporting by Jason Szep, editing by Philip Barbara)