We reviewed 26 studies with 27 treatment groups that enrolled a total of 4893 participants. Twenty five of the studies were case series or uncontrolled long-term trial continuations, the other was an RCT comparing two opioids. Opioids were administered orally (number of study treatments groups [abbreviated as "k"] = 12, n = 3040), transdermally (k = 5, n = 1628), or intrathecally (k = 10, n = 231). Many participants discontinued due to adverse effects ( oral : % [95% confidence interval ( CI ): % to %]; transdermal: % [95% CI : % to %]; intrathecal: % [95% CI : % to %]); or insufficient pain relief ( oral : % [95% CI : % to %]; intrathecal: % [95% CI : % to %]; transdermal: % [95% CI : % to %]). Signs of opioid addiction were reported in % of participants in the studies that reported that outcome . All three modes of administration were associated with clinically significant reductions in pain, but the amount of pain relief varied among studies. Findings regarding quality of life and functional status were inconclusive due to an insufficient quantity of evidence for oral administration studies and inconclusive statistical findings for transdermal and intrathecal administration studies.
A meta-analysis of 34 studies found a reduced risk of mortality from coronary heart disease in men who drank 2 - 4 drinks per day and women who drank 1 - 2 drinks per day.  Alcohol has been found to have anticoagulant properties.   Thrombosis is lower among moderate drinkers than abstainers.  A meta-analysis of randomized trials found that alcohol consumption in moderation decreases serum levels of fibrinogen, a protein that promotes clot formation, while it increases levels of tissue type plasminogen activator, an enzyme that helps dissolve clots.  These changes were estimated to reduce coronary heart disease risk by about 24%. Another meta-analysis in 2011 found favorable changes in HDL cholesterol, adiponectin, and fibrinogen associated with moderate alcohol consumption.