The journal of pain : official journal of the American Pain Society
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Comparative Study
Differences in prescription opioid analgesic availability: comparing minority and white pharmacies across Michigan.
Little is known about physical barriers to adequate pain treatment for minorities. This investigation explored sociodemographic determinants of pain medication availability in Michigan pharmacies. A cross-sectional survey-based study with census data and data provided by Michigan community retail pharmacists was designed. Sufficient opioid analgesic supplies was defined as stocking at least one long-acting, short-acting, and combination opioid analgesic. Pharmacies located in minority (
or=70% white residents) zip code areas were randomly selected by using a 2-stage sampling selection process (response rate, 80%). For the 190 pharmacies surveyed, most were located in white areas (51.6%) and had sufficient supplies (84.1%). After accounting for zip code median age and stratifying by income, pharmacies in white areas (odds ratio, 13.36 high income vs 54.42 low income) and noncorporate pharmacies (odds ratio, 24.92 high income vs 3.61 low income) were more likely to have sufficient opioid analgesic supplies (P < .005). Racial differences in the odds of having a sufficient supply were significantly higher in low income areas when compared with high income areas. Having a pharmacy located near a hospital did not change the availability for opioid analgesics. Persons living in predominantly minority areas experienced significant barriers to accessing pain medication, with greater disparities in low income areas regardless of ethnic composition. Differences were also found on the basis of pharmacy type, suggesting variability in pharmacist's decision making. ⋯ Michigan pharmacies in minority zip codes were 52 times less likely to carry sufficient opioid analgesics than pharmacies in white zip codes regardless of income. Lower income areas and corporate pharmacies were less likely to carry sufficient opioid analgesics. This study illustrates barriers to pain care and has public health implications. -
In this study we investigated the involvement of cutaneous versus knee joint afferents in the antihyperalgesia produced by transcutaneous electrical nerve stimulation (TENS) by differentially blocking primary afferents with local anesthetics. Hyperalgesia was induced in rats by inflaming one knee joint with 3% kaolin-carrageenan and assessed by measuring paw withdrawal latency to heat before and 4 hours after injection. Skin surrounding the inflamed knee joint was anesthetized using an anesthetic cream (EMLA). Low (4 Hz) or high (100 Hz) frequency TENS was then applied to the anesthetized skin. In another group, 2% lidocaine gel was injected into the inflamed knee joint, and low or high frequency TENS was applied. Control experiments were done using vehicles. In control and EMLA groups, both low and high frequency TENS completely reversed hyperalgesia. However, injection of lidocaine into the knee joint prevented antihyperalgesia produced by both low and high frequency TENS. Recordings of cord dorsum potentials showed that both low and high frequency TENS at sensory intensity activates only large diameter afferent fibers. Increasing intensity to twice the motor threshold recruits Adelta afferent fibers. Furthermore, application of EMLA cream to the skin reduces the amplitude of the cord dorsum potential by 40% to 70% for both high and low frequency TENS, confirming a loss of large diameter primary afferent input after EMLA is applied to the skin. Thus, inactivation of joint afferents, but not cutaneous afferents, prevents the antihyperalgesia effects of TENS. We conclude that large diameter primary afferent fibers from deep tissue are required and that activation of cutaneous afferents is not sufficient for TENS-induced antihyperalgesia. ⋯ Transcutaneous electrical nerve stimulation (TENS) is an accepted clinical modality used for pain relief. It is generally believed that TENS analgesia is caused mainly by cutaneous afferent activation. In this study by differentially blocking cutaneous and deep tissue primary afferents, we show that the activation of large diameter primary afferents from deep somatic tissues, and not cutaneous afferents, are pivotal in causing TENS analgesia.
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Randomized Controlled Trial
A randomized, placebo-controlled trial of bupropion sustained release in chronic low back pain.
Clinical trials of the efficacy of antidepressant drugs in patients with chronic low back pain have had mixed results, possibly because of the different mechanisms of action of the drugs that have been studied. Because bupropion has a mechanism of action that differs from other antidepressants and has shown efficacy in neuropathic pain, a randomized, placebo-controlled, 2-period crossover trial was conducted to evaluate its efficacy in subjects with chronic low back pain. The primary efficacy variable was mean daily diary pain intensity ratings, and secondary pain intensity and relief outcomes included weekly pain intensity ratings, the McGill Pain Questionnaire (MPQ) Present Pain Intensity scale, pain relief ratings, and satisfaction with pain relief ratings. Adverse events were also assessed throughout the trial. Analyses were performed of an intention-to-treat sample of 44 patients, only 3 of whom met criteria for neuropathic low back pain. Daily and weekly pain intensity ratings, the MPQ Present Pain Intensity scale, and pain relief ratings were not significantly different following treatment with bupropion sustained release (SR) vs. placebo. These results suggest that bupropion SR was not significantly better than placebo in the treatment of patients with non-neuropathic chronic low back pain. ⋯ Antidepressant medications that have both noradrenergic and serotonergic effects appear to have greater efficacy in patients with chronic low back pain than those with only serotonergic activity. We studied bupropion because it inhibits the reuptake of both norepinephrine and dopamine, but found no evidence of efficacy in patients with non-neuropathic chronic low back pain.
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Multicenter Study
Pediatric surgeons and pediatric emergency physicians' attitudes towards analgesia and sedation for incarcerated inguinal hernia reduction.
Inguinal hernias become incarcerated in 10% to -15% of children and reduction of the hernia is an urgent painful procedure. No recommendations exist for analgesia during this procedure. We surveyed pediatric emergency physicians (PEP) and pediatric surgeons (PS) for their analgesia and sedation use during the reduction. The survey was mailed to 19 centers in North America. A total of 56% (185/331) surveys were completed by PEP and 56% (68/122) from PS. A total of 96.7% (245/253) of responders reported giving analgesia or sedation during reduction. PS were more likely to use intravenous drugs, try for a longer time, wait longer between trials, and conduct more trials compared to the PEP. Clinically related variables were more important for PEPs than PS for analgesia and sedation. System-related variables were more important by PS for admission. ⋯ This survey shows significant variability between specialties in the drugs, route, and number of attempts during reduction of a painful incarcerated hernia in children. Development of a sedation and analgesia protocol may be useful in order to unify management of pain and discomfort during hernia reduction.
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Case Reports
Cervicogenic headache in patients with presumed migraine: missed diagnosis or misdiagnosis?
The differential diagnosis of headache is often challenging, with significant clinical and socioeconomic consequences of incomplete or inaccurate diagnosis. Overlapping symptoms contribute to the diagnostic challenge. Four female patients, ages 26 to 69 with standing diagnoses of migraine, were evaluated and treated for complaints of chronic, severe headaches. All had obtained limited relief from migraine therapies. On physical examination, all had occipital nerve tenderness or positive Tinel sign over the occipital nerve. All responded well to occipital nerve blocks with local anesthetic, achieving complete or substantial pain relief lasting up to 2 months. We conclude that accurate diagnosis of occipital neuralgia or cervicogenic headache as contributing factors can lead to substantial headache relief through occipital nerve blocks in patients with coexisting or misdiagnosed migraine. ⋯ The pathophysiology of many types of chronic headaches is not well understood. Mixed mechanisms such as neurovascular, neuropathic, myofascial, and cervicogenic may all contribute. Our four patients with chronic headaches responded well to occipital nerve blocks. The neuroanatomical relationship between the trigeminocervical nucleus and occipital nerve may serve as the basis of efficacy for these blocks.