Narcotic painkiller-related deaths have increased in the United States in the past few years, federal researchers said in a report released Tuesday.

According to National Center for Health Statistics, fatal overdoses of prescription narcotic painkillers rose from 1.4 per 100,000 people in the year 1999 to 5.4 per 100,000 in 2011. Hydrocodone (Vicodin), morphine and oxycodone (Oxycontin) are some examples of drugs that saw most deaths due to overdoses. NCHS is part of the Centers for Disease Control and Prevention.

The good news is that despite the rise of fatal overdoses, the rate of increase has actually slowed down.

"Although the rate is still increasing, it is not increasing quite as fast as it did between 2000 and 2006," said Holly Hedegaard, epidemiologist at CDC's National Center for Health Statistics (NCHS), according to HealthDay. "From 1999 to 2006, the rate of deaths increased about 18 percent per year, but since 2006 it's only increasing about 3 percent per year."

According to NCHS, natural and semisynthetic opioid analgesics were involved in 2,749 deaths in 1999, whereas in 2011 they accounted for as many as 11,693 fatal overdoses.

Another class of drugs - Benzodiazepines - saw a 13 percent rise in analgesic poisoning deaths, the report said. These drugs are used as sedatives in patients suffering from anxiety, insomnia and seizures. A related study, published recently in the British Medical Journal, has found that long-term users of benzodiazepines are at an increased risk of developing Alzheimer's disease.

The report shows that non-Hispanic white persons, aged between 55 and 64 years, witnessed the greatest rise in rate of opioid painkiller-related deaths.

According to Dr. Andrew Kolodny, president of Physicians for Responsible Opioid Prescribing and chief medical officer of the Phoenix House Foundation in New York City, doctors are cautious in prescribing these painkillers to minorities than Caucasians. This difference has helped lower prescription painkiller-related overdoses in minority communities.

"Doctors prescribe narcotic painkillers much more cautiously to their non-white patients," he told HealthDay. "When doctors have a black or Latino patient, they are more concerned about the possibility of addiction or diversion of the drug-patients selling the medication-so they prescribe more cautiously. Stereotyping is having a protective effect on minorities."