Deaths and injuries related to prescription drugs hit record levels in the first quarter of 2008, according to a report released Wednesday by the Horsham, Pa.-based Institute for Safe Medication Practices, a watchdog group.

The analysis found that the Food and Drug Administration received nearly 21,000 reports of serious drug reactions, including more than 4,800 deaths. The numbers represent a nearly threefold increase in deaths from the previous quarter and a 38 percent increase in injuries from last year’s quarterly average.

The FDA defines serious drug reactions as ones causing hospitalization, requiring medical intervention or placing a life in jeopardy.

Anti-smoking drug varenicline and the blood thinner heparin were the most dangerous medications. The first was linked to 1,001 injuries and 50 deaths in the three-month period ending in March, while the second was associate with 779 injuries and 102 deaths. The heparin cases were linked to contaminated lots of the drug imported from China. Varenicline sold in the US by Pfizer Inc. under the brand name Chantix was linked to 3,325 serious injuries and 112 deaths since its approval in 2006. Some reports were linked to people attempting suicide or causing other injuries to themselves after using the smoking cessation drug. Other reports were linked to blackouts or loss of consciousness tied probably to disturbances in heart rhythm.

Earlier this year, the FDA warned that Chantix may be linked to psychiatric problems, including suicidal behavior and vivid dreams. Following the report release, FDA confirmed the number of injuries and deaths linked to Chantix and further said that it “is reviewing these reports to see if current labeling related to accidents after varenicline is adequate,” FDA’s spokesman Christopher DiFrancesco said.

 On the other hand, Pfizer continues to stand by its drug saying that it has an acceptable “efficacy and safety profile” and is “an important treatment option to help patients stop smoking.”