Darvon Risk Reviewed in 2006 VHA Study

July 20th, 2009. By AbiK

Back in March 2006, the VHA Pharmacy Benefits Management Strategic Healthcare Group and the Medical Advisory Panel conducted a review of the Efficacy and Safety of Propoxyphene (aka, Darvon). The study concluded that the group…

found no substantive evidence to alter our previous conclusions about the efficacy and safety of propoxyphene relative to other opioids. Our recommendations on the use of propoxyphene in the Veterans Health Administration remain essentially the same as in the previous review.

In the majority of VA patients with mild to moderate acute pain and who do not have certain characteristics associated with intentional or unintentional overdose, single-dose or short-term therapy with DPP+/-APAP probably provides adequate analgesia with an acceptable safety profile. The efficacy and safety of long-term therapy with DPP+/-APAP for treatment of chronic pain has not been adequately studied.

However, that does not mean the study did not find significant reported adverse effects for use of propoxyphene. The study references 2004 data from the American Association of Poison Control Centers Toxic Exposure Surveillance System (AAPCC TESS) which shows a comparison of adverse drug reactions (ADR’s) for substances listed by analgesic class. The data for opioids (of which propoxyphene is one) is below.

Substance	No. of Exposures	No. ADR’s	%
Meperidine	444	58	13.1%
Morphine	3097	288	9.3%
Pentazocine	175	16	9.1%
Tramadol	3769	324	8.6%
Codeine	1281	98	7.7%
D-propoxyphene	417	27	6.5%
Methadone	3965	244	6.2%
Oxycodone	5510	327	5.9%
Other/unknown opioid	6974	897	12.9%

What’s interesting is that a couple of pages later in the study, there is a chart showing the “Moderate, major, and fatal medical outcomes associated with selected analgesic exposures by drug class in decreasing order of moderate outcome frequency (%)”. The interesting part is that when viewed through this lens, d-propoxyphene ranks second only to methadone for moderate and major outcomes-and death. 

Still, at the time of this study, the VHA only specified the following conditions as those in which a patient should NOT receive propoxyphene (“Criteria for Nonformulary Use of Propoxyphene”, October 2006, www.pbm.va.gov):

• Current history of suicidal ideation, suicide attempt, or depression
• History or propensity of drug overdose (e.g., taking more than prescribed doses), misuse, abuse, addiction/dependence, or diversion
• Current diagnosis of alcohol abuse or dependence
• Current or past history of seizures
• Impairment of renal or hepatic function
• More than 4 doses per day or greater than 390mg per day of propoxyphene HCl (600mg per day propoxyphene napsylate) is required for pain relief

The VHA guidelines urge CAUTION for the following conditions:

• Past history of suicidal ideation, suicide attempt or depression or current or past history of emotional disturbances or other psychiatric disorder
• Concurrent treatment with sedatives, tranquilizers, muscle relaxants, antidepressants, or other CNS-depressant drugs
• Excessive alcohol intake or distant history of alcohol abuse or dependence
• Pregnant or nursing
• Use in the elderly (due to decreased metabolism)
• Current or past history of cardiac arrhythmias or prolonged conduction times on ECG (QRS interval)

Tags: darvocet, darvon, propoxyphene

This was posted on Monday, July 20th, 2009 at 11:28 am and is filed under Drugs/Medical, Personal Injury . Feel free to respond, or trackback. Read our comments policy.