Drugs
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Chemotherapy-induced emesis has a major adverse impact on patients undergoing therapy for various malignancies, and this has led to considerable research in this field. Most investigative efforts have concentrated on the acute phase of emesis that occurs within the first 24 hours after chemotherapy, and significant strides forward have been made with this problem. Better control of acute emesis with newer agents such as the serotonin 5-HT3 receptor antagonists has focused increasing attention on a second phase of nausea and vomiting, known as delayed emesis, which occurs more than 24 hours after chemotherapy. ⋯ Efforts are ongoing to identify more effective treatments for delayed emesis. One novel approach involves the blockade of substance P binding to neurokinin-1 (NK1) receptors. This article reviews what is currently known about chemotherapy-induced delayed emesis, with a focus on treatment strategies.
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Primary Raynaud's phenomenon is common, particularly in younger women, and may be familial. Vasospasm is not confined to the digits and may involve, for example, the tongue and nose, and also visceral organs like the heart, oesophagus or lung and cerebral circulation. Symptoms tend to be milder in primary compared with secondary Raynaud's phenomenon, which is associated with other disorders such as the connective tissue diseases. ⋯ Essential fatty acid supplementation is mildly effective, while ketanserin and calcitonin gene-related peptide both look promising. Lumbar sympathectomy retains its important role in the treatment of Raynaud's phenomenon involving the lower limbs. Satisfactory symptomatic relief is now possible for many patients with Raynaud's phenomenon and this should certainly be the aim for all patients seeking medical help.
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Irinotecan (CPT-II) is a semisynthetic derivative of camptothecin. It and other camptothecin analogues/derivatives appear to exert their antitumour activity by binding to topoisomerase I. The active metabolite of irinotecan, 7-ethyl-10-hydroxycamptothecin (SN-38), has demonstrated potent growth inhibition of human colorectal cancer cells in vitro, with superior activity to fluorouracil. ⋯ Importantly, irinotecan also induced responses in some patients with tumours refractory to fluorouracil. Severe (grade 3 or 4) neutropenia and diarrhoea, which occurred in up to 40% of patients receiving irinotecan therapy in phase II studies, require careful monitoring and appropriate management. Thus, irinotecan is a valuable agent for the second-line treatment of patients with advanced colorectal cancer who fail to respond to or relapse after fluorouracil therapy.
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Remifentanil is a new selective mu opioid receptor agonist of higher potency than alfentanil, with pharmacological effects that essentially parallel those of alfentanil and other opioids in this class. Unlike other opioids, remifentanil is rapidly hydrolysed by nonspecific plasma and tissue esterases: this imparts brevity of action, precise and rapidly titratable effects (due to rapid onset and offset), non-cumulative opioid effects and rapid recovery after cessation of administration. The onset of action of remifentanil is similar to that of alfentanil, although its offset is considerably more rapid and independent of the duration of infusion. ⋯ Its brevity of action ensures not only a rapid resolution of adverse effects but also a rapid offset of analgesic effect. Therefore, appropriate postoperative analgesia, when necessary, should be established before discontinuation of remifentanil infusion. The unique pharmacokinetic profile of remifentanil facilitates 'real time' management of intraoperative stress, as well as provision of optimal intraoperative analgesia without compromising recovery for a variety of surgical procedures.
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The enantiomerically pure (S-enantiomer) amide local anaesthetic drug ropivacaine blocked nerve fibres responsible for transmission of pain (A delta and C fibres) more completely than those that control motor function (A beta fibres) in in vitro studies. The drug shares the biphasic vascular effects common to the amide local anaesthetic drug class. In vitro studies indicate that ropivacaine is less cardiotoxic than equimolar concentrations of bupivacaine. ⋯ Thus, ropivacaine, according to animal data, is less cardiotoxic than bupivacaine. Based on available clinical data, ropivacaine appears to be as effective and well tolerated as bupivacaine when equianalgesic doses are compared. The greater degree of separation between motor and sensory blockade seen withropivacaine relative to bupivacaine at lower concentrations (approximately 5 mg/ml) will be advantageous in certain applications.