Pharmacotherapy
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Conditions in which antidepressants have been used include diabetic neuropathy, postherpetic neuralgia, headaches, arthritis, chronic back pain, cancer, thalamic pain, facial pain, and phantom limb pain. Although much of the available information is derived from inadequately controlled trials, it seems that antidepressants provide analgesia in many of these disorders. The analgesic effects tend to be independent of antidepressant effects, and doses of heterocyclic antidepressants used for analgesia seem to be lower than those considered effective in the treatment of depression. ⋯ Onset of analgesia is variable, ranging from 1 day to 10 weeks. Common side effects include dry mouth, drowsiness, urinary retention, orthostatic hypotension, and constipation. Optimum dosages and schedules have not been established.
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Cancer chemotherapy is associated with numerous toxicities such as nausea and vomiting (emesis). The frequency, onset, and duration of emesis depend largely on the emetogenic potential of specific agents. An exact mechanism for chemotherapy-induced emesis (CIE) is not known but is thought to occur through several noxious actions and numerous neuronal pathways. ⋯ Investigational agents such as serotonin antagonists may prove to be effective with few toxic effects. Despite the minimal information available on delayed and anticipatory nausea and vomiting, attempts should be made to treat them. Suggested guidelines for the management of CIE have been developed.
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Randomized Controlled Trial Clinical Trial
The effect of theophylline on respiratory muscle contractility and fatigue.
The traditional role of theophylline as a bronchodilator has been expanded by recent findings that suggest this drug has more than smooth muscle relaxant properties. Several investigators indicate that theophylline has an inotropic effect on respiratory muscle, causing enhanced muscular contraction and prevention of muscle fatigue. In animal studies, the drug enhanced respiratory muscle contraction by 15-20%, with levels in the upper end of the therapeutic range (15-20 mg/L). ⋯ Disparity in outcomes may be attributed to differences in patient populations, study designs, and techniques used to determine diaphragmatic contractility. Few long-term trials exist that document significant clinical benefit. Theophylline may prove to be of value in selected populations, such as adults with hypercapnic obstructive lung disease.
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This investigation was conducted to determine if measurements of bioelectrical impedance in conjunction with serum creatinine concentrations are useful in predicting creatinine clearance. Twenty-eight healthy volunteers between 23 and 50 years of age followed an individualized protein diet to provide 1.2 g protein/kg/day for 3 consecutive days. At the beginning of day 3, a 24-hour urine collection was initiated. ⋯ The measured creatinine clearance was compared to that predicted by the impedance-derived model that we developed, as well as other established estimation methods. Mean absolute prediction errors in creatinine clearance using this model were significantly lower than those obtained using four empiric methods. Bioelectrical impedance may provide a noninvasive, quick, and accurate method for predicting creatinine clearance from serum creatinine concentration values.
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A new transdermal drug-delivery system that administers the synthetic opioid fentanyl through intact skin was evaluated for 24 hours postoperatively in eight patients who had undergone orthopedic surgery. Plasma samples were obtained over a 72-hour period for pharmacokinetic analysis in five patients. The patients were also evaluated intensively for adequacy of analgesia, frequency of nausea and sedation, and occurrence of ventilatory depression. ⋯ Four patients required no additional analgesia. No consistent correlations among fentanyl concentration and any clinical values were observed. Transdermal administration of fentanyl appears to be a viable alternative to conventional routes of narcotic administration and warrants further study.