Pubdate: Sun, 31 Aug 2014
Source: New York Times (NY)
Copyright: 2014 The New York Times Company
Contact: http://www.nytimes.com/ref/membercenter/help/lettertoeditor.html
Website: http://www.nytimes.com/
Details: http://www.mapinc.org/media/298
Authors: Marcus Bachhuber and Colleen Barry
Note: Marcus Bachhuber, an internist, is a clinical scholar at the 
Philadelphia V.A. Medical Center. Colleen Barry is an associate 
professor of health policy and management at the Johns Hopkins 
Bloomberg School of Public Health.

OF POT AND PERCOCET

PRESCRIPTION opioid painkillers like Percocet, Vicodin and OxyContin 
have come under intense scrutiny in recent years because of the 
drastic rise in overdose deaths associated with their prolonged use. 
Meanwhile, access to medical marijuana has been expanding - 23 states 
and the District of Columbia have legalized its broad medical use - 
and chronic or severe pain is by far the most common condition 
reported among people using it.

Could the availability of medical marijuana reduce the hazards of 
prescription painkillers? If enough people opt to treat pain with 
medical marijuana instead of prescription painkillers in states where 
this is legal, it stands to reason that states with medical marijuana 
laws might experience an overall decrease in opioid painkiller 
overdoses and deaths.

To find out if this has actually happened, we and our colleagues 
Brendan Saloner and Chinazo Cunningham studied opioid overdose deaths 
in the United States from 1999 to 2010. Our findings, which were 
published on Monday in the journal JAMA Internal Medicine, suggest 
that this unexpected benefit of medical marijuana laws does exist.

Pinpointing the effect of laws on health is notoriously difficult. 
For one thing, states that have passed medical marijuana laws are no 
doubt different in important ways from states that have not passed 
such laws. Differences in, say, social attitudes about drug use or 
overall health trends might affect rates of opioid painkiller deaths, 
independent of whether medical marijuana is legal.

Furthermore, from 1999 to 2010 (the period of time we studied), 
states implemented various measures in response to the threat of 
opioid painkiller overdoses, including central registries of 
controlled substance prescriptions, laws allowing pharmacists to 
request identification before filling a prescription and laws 
increasing oversight of pain management clinics. These measures, too, 
might affect rates of opioid painkiller deaths, regardless of the 
legality of medical marijuana.

We designed our study to allow us to compare state-level rates of 
opioid painkiller overdose deaths before and after the passage of 
medical marijuana laws, while controlling for these and other 
concurrent state and national trends.

Using death certificates compiled by the Centers for Disease Control 
and Prevention, we found that the rate of prescription painkiller 
overdose deaths increased in all states from 1999 to 2010. But we 
also found that implementation of a medical marijuana law was 
associated with a 25 percent lower yearly rate of opioid painkiller 
overdose deaths, on average. In absolute terms, we estimated that 
states with a medical marijuana law had a total of about 1,700 fewer 
opioid painkiller overdose deaths in 2010 than would be expected 
based on trends before the laws were passed.

This is the first study that we know of to suggest that medical 
marijuana laws could contribute to a decline in drug overdose deaths, 
and therefore it should be read with caution. Our study was not a 
controlled experiment, and it is possible that states with and 
without medical marijuana laws differed over time in important ways 
that we did not or cannot measure and that could explain, at least in 
part, our results.

However, if medical marijuana laws are in fact reducing opioid 
overdose deaths, the next step is to figure out how and why. That 
people are replacing opioid painkillers in part or entirely with 
medical marijuana for chronic pain treatment is one possibility. 
Another possibility is that the availability of medical marijuana is 
changing the behavior of people who are addicted to and abuse or 
misuse opioids. We know that marijuana and opioids stimulate a common 
receptor in the brain's reward pathways, but we don't know whether 
people who misuse or abuse opioids for recreational purposes would 
switch to marijuana in states where it is legal for medical purposes.

We hope the results of our study will spur further scientific 
investigation into the effects of these laws as well as the ways in 
which medical marijuana can and should be used in clinical practice.
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MAP posted-by: Jay Bergstrom