Medical cannabis: A forward vision for the clinician.

Medical cannabis has entered mainstream medicine and is here to stay. Propelled by public advocacy, the media and mostly anecdote rather than sound scientific study, patients worldwide are exploring marijuana use for a vast array of medical conditions including management of chronic pain. Contrary to the usual path of drug approval, medical cannabis has bypassed traditional evidence-based study and has been legalized as a therapeutic product by legislative bodies in various countries. While there is a wealth of basic science and preclinical studies demonstrating effects of cannabinoids in neurobiological systems, especially those pertaining to pain and inflammation, clinical study remains limited. Cannabinoids may hold promise for relief of symptoms in a vast array of conditions, but with many questions as yet unanswered. Rigorous study is needed to examine the true evidence for benefits and risks for various conditions and in various patient populations, the specific molecular effects, ideal methods of administration, and interaction with other medications and substances. In the context of prevalent use, there is an urgency to gather pertinent clinical information about the therapeutic effects as well as risks. Even with considerable uncertainties, the health care community must adhere to the guiding principle of clinical care 'primum non nocere' and continue to provide empathetic patient care while exercising prudence and caution. The health care community must strongly advocate for sound scientific evidence regarding cannabis as a therapy. SIGNIFICANCE: Legalization of medical cannabis has bypassed usual drug regulatory procedures in jurisdictions worldwide. Pending sound evidence for effect in many conditions, physicians must continue to provide competent empathetic care with attention to harm reduction. A vision to navigate the current challenges of medical cannabis is outlined.

Antiviral efficacy and pharmacokinetics of oral adefovir dipivoxil in chronically woodchuck hepatitis virus-infected woodchucks.

The antiviral efficacy of orally administered adefovir dipivoxil was evaluated in an 18-week study (12 weeks of treatment and 6 weeks of recovery) conducted with woodchucks chronically infected with woodchuck hepatitis virus (WHV). Adefovir dipivoxil is a prodrug of adefovir designed to enhance its oral bioavailability. Following administration of 15 mg of adefovir dipivoxil per kg of body weight in four WHV-infected animals, the mean maximum concentration of adefovir in serum was 0.462 microg/ml, with an elimination half-life of 10.2 h, and the oral bioavailability of adefovir was estimated to be 22.9% (+/-11.2%). To study antiviral efficacy, the animals were divided into three groups. There were six animals each in a high-dose group (15 mg/kg/day) and a low-dose group (5 mg/kg/day). A vehicle control group consisted of five animals because WHV DNA was detectable only by PCR at the time of the study in one of the original six animals. Efficacy was evaluated by determining the levels of WHV DNA in serum. The geometric mean WHV DNA level for the high-dose group diminished by >40-fold (>1.6 log(10)) after 2 weeks of treatment and >300-fold (>2.5 log(10)) at 12 weeks. There was a >10-fold reduction in five of six low-dose animals by 2 weeks, but levels were unchanged in one animal. By 12 weeks of treatment there was a >45-fold (>1.6 log(10)) reduction of WHV DNA levels, and serum WHV DNA levels were below the limit of quantification in three of six animals. Viral DNA levels returned to pretreatment levels during the 6-week recovery period. There were no clinically significant changes in body weight, hematology, or serum chemistry values, including bicarbonate or lactate, in any of the treated animals. No histologic evidence of liver injury was apparent in the biopsies. Under the conditions of this study, adefovir dipivoxil was an effective antihepadnaviral agent.

Effect of salicis cortex extract on human platelet aggregation.

The bark of Salix species contains several prodrugs of salicylate, mainly salicin. The aim of this study was to investigate if during pain treatment with Salicis cortex extract platelet aggregation was affected. A total of 51 patients were enrolled in the study. Thirty-five patients suffering from acute exacerbations of chronic low back pain received randomly and double-blind either Salicis cortex extract with 240 mg salicin/day (n = 19) or placebo (n = 16). Further sixteen patients with stable chronic ischemic heart disease were given 100 mg acetylsalicylate per day. Platelet aggregation was studied using an aggregometer. As aggregating agents, arachidonic acid (500 micrograms/ml), adenosine di-phosphate (2 x 10(-5) M) and collagen (0.18 microgram/ml) were used. The mean maximal arachidonic acid induced platelet aggregation was 61%, 78% and 13% in the Salicis cortex extract, placebo and acetylsalicylate groups. Acetylsalicylate had a significant inhibitory effect on platelet aggregation compared to Salicis cortex extract (p = 0.001) and placebo (p = 0.001). There was also a significant difference between the placebo and the willow bark-treated groups in the maximal platelet aggregation induced by arachidonic acid (p = 0.04) and ADP (p = 0.01). No statistical difference was found between the groups when collagen was applied to the human platelets. Daily consumption of Salicis cortex extract with 240 mg salicin per day affects platelet aggregation to a far lesser extent than acetylsalicylate. Further investigation needs to clarify if this finding is of clinical relevance in patients with impaired thrombocyte function.

Treatment of low back pain exacerbations with willow bark extract: a randomized double-blind study.

PURPOSE: Herbal medicines are widely used for the treatment of pain, although there is not much information on their effectiveness. This study was designed to evaluate the effectiveness of willow (Salix) bark extract, which is widely used in Europe, for the treatment of low back pain. SUBJECTS AND METHODS: We enrolled 210 patients with an exacerbation of chronic low back pain who reported current pain of 5 or more (out of 10) on a visual analog scale. They were randomly assigned to receive an oral willow bark extract with either 120 mg (low dose) or 240 mg (high dose) of salicin, or placebo, with tramadol as the sole rescue medication, in a 4-week blinded trial. The principal outcome measure was the proportion of patients who were pain-free without tramadol for at least 5 days during the final week of the study. RESULTS: The treatment and placebo groups were similar at baseline in 114 of 120 clinical features. A total of 191 patients completed the study. The numbers of pain-free patients in the last week of treatment were 27 (39%) of 65 in the group receiving high-dose extract, 15 (21%) of 67 in the group receiving low-dose extract, and 4 (6%) of 59 in the placebo group (P <0.001). The response in the high-dose group was evident after only 1 week of treatment. Significantly more patients in the placebo group required tramadol (P <0.001) during each week of the study. One patient suffered a severe allergic reaction, perhaps to the extract. CONCLUSION: Willow bark extract may be a useful and safe treatment for low back pain.

Spinal cord stimulator activation by an antitheft device. Case report.

The authors present a case in which electrical injury to the central nervous system resulted from uncontrolled activation of a cervical spinal cord stimulation device by an antitheft device. The injury resulted in long-term neurological sequelae.

Postprandial transient painful amaurosis fugax.

A case of recurrent postprandial amaurosis fugax (AF) associated with periorbital pain is described. Clinical and angiographic examination revealed moderate atherosclerosis of the cerebral vessels and narrow-angle glaucoma. Cerebral postprandial hypoperfusion combined with increased intraocular pressure probably precipitated the painful monocular blindness. The attacks of AF subsided partially after treatment of the glaucoma.

Epidermoid carcinoma of the gingiva: a possible relationship to PUVA therapy.

A case of squamous cell carcinoma arising in the gingiva of a 30-year-old nonsmoking woman receiving PUVA therapy for vitiligo is reported. There were no typical predisposing factors for oral cancer in the history, other than the latter therapy. Although there are several previous reports of cutaneous carcinoma developing in patients under PUVA therapy, most of such involve development of tumors on skin surfaces exposed to direct ultraviolet radiation either through sunlight or via therapeutic mode.s In this case, there was no direct ultraviolet exposure at the site of carcinoma. We suggest the possibility that, in this case, PUVA may exerted a carcinogenic influence via systemic distribution of ultraviolet-activated psoralens or its metabolites to the gingiva. The possibility of microbial interaction with substances within gingival inflammatory exudate to produce carcinogenic substances is postulated.