Pot Over Pills – Using Medical Cannabis to Decrease the Use of Prescription Drugs

Pot Over Pills. Using Medical Cannabis to Decrease the Use of Prescription Drugs.

With increasing evidence for its effectiveness, more and more Americans are turning to cannabis to treat diseases such as glaucoma, cancer, anxiety, and chronic pain.

Cannabis is increasingly being viewed as a treatment option for many diseases, with 24 states and the District of Columbia allowing cannabis use in some form to treat approved conditions.  With increasing evidence for its effectiveness, more and more Americans are turning to cannabis to treat diseases such as glaucoma, cancer, anxiety, and chronic pain.  But what effect is the addition of medical marijuana laws having on the use of prescription medications?  Three recent studies have examined what happens when medical cannabis is added to the mix of treatment options.

Prescription opioid use has increased significantly in the United States over the past 15-20 years.  Sales of prescription opioids (such as hydrocodone, oxycodone, and morphine) in the U.S. nearly quadrupled from 1999 to 2014.  In 2014, more than 240 million prescriptions were written for prescription opioids, which is more than enough to give every American adult their own bottle of pills.  Opioid overdose accounted for nearly 165,000 deaths from 1999-2014, including nearly 14,000 in 2014 alone.  In states with medical cannabis programs, chronic pain is the leading documented reason for use of medical cannabis.  In the largest and longest study of its kind, investigators from the University of Pennsylvania reviewed state-by-state mortality data from the CDC from 1999-2010.   Researchers compared trends in rates of death due to opioid overdose in states that had medical cannabis programs to those that did not.  They used a model, based on those data trends, to predict expected rates of opioid-associated overdose deaths in both groups, then compared them to the actual rate.  To account for economic factors in rates of death due to opioids, researchers compared unemployment rates between states with medical cannabis and those without.  They also compared differences in these two groups regarding restrictions on prescription opioid dispensing, such as prescription drug monitoring programs, requirements for presenting identification when picking up opioid and increased state oversight of pain management clinics. To account for the possibility of decreased deaths due to overall improvements in health, they compared states with and without medical cannabis laws on rates of death due to two non-drug causes: heart disease and sepsis (an overwhelming infection affecting the entire body).  Researchers found no significant difference between states with or without medical cannabis laws in rates of death due to heart disease or sepsis, in opioid-associated deaths when unemployment rates were factored in, or when factors related to control of opioid prescription dispensing were accounted for.  Overall rates of mortality from opioid overdose increased in states both with and without medical cannabis laws, with actually higher rates of opioid overdoses occurring in states with a medical cannabis program than in those without such programs.  However, based on the model predictions,  it showed overall a nearly 25% decrease from the expected rates of death due to opioid overdose in states that had enacted medical cannabis programs compared to those that had not.  As more patients became enrolled in medical cannabis programs, rates of actual-vs-expected deaths due to opioid overdoses were further decreased.  On average, the largest rates of decreases in expected-vs-actual opioid-associated overdose deaths occurred after medical cannabis programs had been in place for at least 5 years. Researchers estimated that states with medical cannabis laws had over 1700 fewer deaths than expected compared with those states  without such laws.

However, the researchers made certain assumptions within the study, based on the state-by-state data trends, and used those assumptions to make predictions about opioid-associated overdose deaths, rather than just looking at the reported data.  While opioid-associated overdose deaths did plateau in 2009 and 2010 in medical cannabis states relative to non-medical cannabis states, rates were still higher in medical cannabis states than non-medical cannabis states. As stated in one of my previous articles, cannabis makes opiates more effective.  This could cause medical cannabis patients to initially take more prescription opioids than needed, potentially leading to an overdose death.  Researchers also were relying on reported data, rather than data they collected.  This data is only as good as the reporting, which is based on codes listed in the death report.  If the codes were reported incorrectly, or were missing, that data could not be included in the study. In addition, investigators did not study if rates or patterns of opioid prescribing had changed in either medical cannabis states or non-medical cannabis states over the 11 year period of the study.

A new study, published in March 2016, did investigate if the ability to use medical cannabis led to a decrease in the use of prescription opiates. Investigators from the University of Michigan surveyed 244 patients who received cannabis for chronic pain from a cannabis dispensary in Michigan from 2013-2015.  They found that among surveyed patients, use of cannabis led to a 64% decrease in the use of prescription opioids.  Patients also reported decreased side effects, and 45% of patients reported improved quality of life.

The predictiveness of this study is limited by the small sample size both in number and geographic locale, and that it relied on the reporting of patients without actually confirming the data (such as with prescription dispensing history). However, this study does seem to point toward a decreased reliance on prescription opioids for pain relief in those with chronic pain.  Future studies could build on this data by reviewing patient dispensing histories before and after initiation of cannabis for chronic pain, by enrolling more patients, and by recruiting patients from multiple states.

While the previous two studies focused only on cannabis for chronic pain, the most recent article to be published focused on the effect of medical cannabis on prescription drug use across multiple indications.  Researchers from the University of Georgia examined the effect on prescription drug dispensing from 2010-2013 for senior citizens on Medicare Part D (prescription drug plan) in states where medical cannabis is legal.  They looked at all prescriptions filled within that time, then focused on prescriptions dispensed for chronic conditions for which medical cannabis could be used. These were anxiety, depression, glaucoma, nausea, pain, psychosis, seizures, sleep disorders and spasticity.  To control for the effects of possible overall decreased prescribing, they also looked at the prescribing habits of drug classes in which medical cannabis is not routinely used, such as antibiotics, blood thinners, and medications to treat the flu.  Average numbers of prescriptions written for the 9 medical cannabis indications were compared, as well as for the control groups.  No difference in prescribing between medical cannabis and non-medical cannabis states was found for antibiotics, blood thinners, or flu treatments.  However, in states where medical cannabis was approved before 2013, the number of prescriptions written decreased in medical cannabis states for 8 of the 9 classes of medication listed above, with only glaucoma prescriptions increasing.  In glaucoma, patients must redose with cannabis every hour (unless patients have access to a longer-acting cannabis extract product), which is impractical for most patients.  And since glaucoma can cause blindness if not effectively treated, most physicians would prefer to write prescriptions for medications that are less difficult for patients to take.  The most significant drop was in prescriptions written for spasticity and chronic pain, decreasing by 20% and 11.5%, respectively over non-medical cannabis states.  In 2013, medical cannabis use by senior citizens was estimated to save the United States government approximately $165.2 million.  It is estimated that if cannabis was legal in all 50 states and U.S. territories, it would have saved the Medicare program an estimated $465 million in 2013.

Unfortunately, this study did not focus on how many Medicare or Medicare-eligible patients were also enrolled in state cannabis programs.  Patients may have decreased use of medications in those classes due to changes in state-specific prescribing practices for those classes of medications, state-specific economic conditions (both of decreased senior income or increased shift to state-sponsored medical programs due to increased state revenues).  However, the study’s large size and widened focus on multiple disease states provide a useful glimpse into yet another benefit of medical cannabis, one that may have a strong influence on lawmakers: increased government revenues paired with decreased government expenditures.

Increased expansion of medical cannabis programs has the potential to decrease reliance on prescription medications and provide additional therapeutic options for patients with chronic illnesses.  Based on the available studies published thus far, medical cannabis has the potential to decrease expenditures of prescription drugs and decrease the risks and side effects associated with many prescription drugs, especially opiates.  With more studies, researchers can pinpoint more accurately which diseases cannabis can treat effectively, reduce side effects, and decrease costs to both government and private insurers alike.

By: Dr. Kit