Articles: patients.
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Long-term administration of morphine for the treatment of chronic pain produces constipation; this requires the use of laxatives, which impair water absorption and upset the electrolyte balance. Morphine-induced constipation is mainly due to inhibition of the propulsive movement of the gastrointestinal tract combined with spastic contraction of smooth circular muscles as a result of drug binding to opioid receptors in the tract. Since papaverine lacks affinity for opioid receptors but relaxes smooth muscle, it seemed possible that oral papaverine might be capable of diminishing constipation without impairing the analgesia achieved with morphine. ⋯ Since in former experiments on nociceptive activity evoked in thalamus neurones it has been found that the ED(50) of i. v. morphine is 0.05 mg/kg, it is very likely that the presystemic elimination of orally administered morphine is very high and, in addition, that the efficiency of its active metabolite, morphine-6-glucuronide, is rather poor. When morphine 2.5 mg/kg was given together with papaverine 0.5 mg/kg, and morphine 5 mg/kg was administered in combination with papaverine 2 mg/kg, there was no significant reduction in the depressant effect of morphine on nociceptive activity evoked in thalamus neurons (Figs. 6, 7). The results suggest that papaverine given by the oral route may reduce morphine-induced constipation without impairment of the analgesic action of morphine in patients suffering from pain.
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The pharmacokinetic variables of drug clearance and volume of distribution are usually corrected for body weight or surface area. Only recently have the relationships which exist between body size, physiologic function and pharmacokinetic variables been evaluated in the obese population. These effects are not widely known, and data on this and the effects of bariatric surgical procedures are scantily documented in the surgical literature. ⋯ Drugs whose distribution is restricted to LBM should utilize a loading dose based on ideal body weight (IBW). For those drugs which distribute freely into adipose tissue, the loading dose should be based on total body weight (TBW). Adjustment of the maintenance dose depends on clearance rates. In a few cases dosage adjustment depends on pharmacodynamic data, since drug clearance does not conform to these recommendations, for reasons which remain to be defined. Following bariatric surgery, in the absence of delayed gastric emptying or uncontrolled diarrhea, drug absorption rates are usually comparable to the non-operated patient.
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WHAT IS HYPOPLASTIC ANEMIA? Aplastic anemia is a hematological disease characterized by pancytopenia and bone marrow hypoplasia. Acquired cases of aplastic anemia are almost all idiopathic and arise from unknown causes. Other cases of aplastic anemia are secondary and are caused by radiation, chemicals or viruses. ⋯ TREATMENT:Aplastic anemia is treated with androgens, high-dose methylprednisolone, cyclosporin A (CyA), antithymocyte globulin (ATG), antilymphocyte globulin (ALG), hematopoietic growth factors such as G-CSF, and bone marrow transplantation. Interestingly, patients who require continuous CyA administration to maintain stable hematopoiesis have a specific HLA class II haplotype (DRB1*1501-DQA1*0102-DQB1*0602) [6]. Recent reports from EBMT SAA Working Party showed the excellent therapeutic result (response rate 82%) when severe cases were treated with ALG, CyA and G-CSF in combination [7].
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COMMENTS FOR PROFESSOR BARRIE R. CASSILETH: I have enjoyed reading the two issues of The Oncologist I've received so far. I would like to make some comments on Dr. ⋯ But most oncologists, like Dr. Quah, indeed are faced with trying to advise patients about therapies for which there is little hard evidence. The best guiding principles at this point are to discourage remedies that promise cancer cure or are promoted for use instead of mainstream treatment, encourage non-invasive, comforting, complementary (adjunctive) therapies such as massage, green tea and qi gong, and check medical journals and newspapers for warnings such as those issued recently for Ma Huang (ephedrine), a still-common ingredient in herbal remedies widely available through catalogs and in health food stores.