Pharmacology & therapeutics
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Drugs used in the acute and long-term management of hypertension in pregnancy and the preeclampsia-eclampsia syndrome have been reviewed and their therapeutic effects and maternal and fetal adverse effects have been considered. The review also focuses on recent developments in the areas of prevention and management of pre-eclampsia-eclampsia syndrome. Although a number of new drugs have emerged, as potentially useful in the management of hypertension in pregnancy and pre-eclampsia-eclampsia syndrome, some remain at the cornerstone of therapy; for example, methyldopa for long-term treatment of chronic hypertension, hydralazine or nifedipine for rapid reduction of severely elevated blood pressure, and magnesium sulphate for eclampsia. ⋯ Safety for the fetus, however, has not been adequately evaluated yet. Neither aspirin nor calcium supplements appear to improve the outcome in pregnancy. Currently, the dilemma whether to treat hypertension in pregnancy and pre-eclampsia-eclampsia syndrome with old, established, cost-effective drugs or the promising newer drugs provides an interesting academic challenge.
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This review discusses the mechanism(s) of general anesthesia from a pharmacological viewpoint; in particular, the ability of drugs to produce many different effects is emphasised. The problems of experimental measurement of general anesthesia are discussed, and the possibilities for antagonism and potentiation of anesthesia considered. Physicochemical studies on anesthesia are described, as are the advancement of ideas beyond consideration of lipids and proteins as separate sites of action. The importance of studies on different areas of the brain is highlighted, and the review finishes with a survey of the effects of general anesthetics on synaptic transmission which emphasises the problems of extrapolation from in vitro to in vivo.
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This review presents an overview of the neurotransmitters and neuromodulators involved in acute and chronic pain. Although there is little evidence that the neuronal pathways differ in the two types of pain, it is clear that different transmitters or receptor types are involved in hyperalgesia and chronic pain. While most attention has been focussed on spinal processes, it is apparent that some types of chronic pain have both a peripheral and a supraspinal component. The presently available drugs are probably adequate for acute pain, but the treatment of chronic pain may need to be tailored to the individual patient.
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The outcome of surgery in the elderly depends on the skill of the surgeon and the expertise of the anaesthetist caring for the patient. This anaesthetic proficiency depends initially on the application of the detailed knowledge of the drugs used during anaesthesia, and on the understanding of the way changes in the elderly patients' physiology with ageing affects both kinetic and dynamic facets of pharmacology. However, the very diversity of the elderly population makes their precise response to drugs unpredictable, and, therefore, clear, unequivocal guidance on practice is limited. ⋯ This review, therefore, deals mainly with the anaesthetic vapours and intravenous drugs, and with neuromuscular blocking agents. The restriction of space and the enormity of the subject demand that the areas covered in this review are solely limited to the major classes of drugs used routinely in general anaesthetic practice in the United Kingdom. The detailed pharmacokinetics and pharmacodynamics of drugs also used in the post-operative period, such as the wide variety of opiates, and of drugs mainly used in general medical practice, but occasionally used as premedicants or supplements during anaesthesia, have been monitored only in passing.
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A neuromuscular blocking agent is an essential component of many general anaesthetics. Although a great deal is known about the neuromuscular junction, the site of action of these agents, their precise mode of action remains unclear. This article reviews our present knowledge of the anatomy and physiology of neuromuscular transmission and the ways in which clinically useful drugs may modify this system. The decisions involved in clinical choice of which agent to use are described with particular respect to basic physiology and pharmacology and also to potential interactions with other drugs.