Drug Safety
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Nondepolarising muscle relaxants block neuromuscular transmission, acting as antagonists of the nicotinic receptors at the neuromuscular junction. Their undesired effects are frequently caused by interaction with acetylcholine receptors outside this junction, and autonomic cardiovascular effects may result. ⋯ Although many complications of these drugs (such as prolonged block or resistance) are easily treated, others may necessitate immediate intervention and vigorous therapy. Careful selection of an appropriate relaxant for a particular patient will usually prevent the occurrence of complications.
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Review
Adverse effects of depolarising neuromuscular blocking agents. Incidence, prevention and management.
Muscle relaxants block neuromuscular transmission, acting at nicotinic acetylcholine receptors of the neuromuscular junction. Suxamethonium (succinylcholine) is a depolarising agent, whereas all other relaxants in clinical use are nondepolarising. The desired neuromuscular block results from the structural similarity of muscle relaxants to acetylcholine, enabling the interaction with receptors at the neuromuscular junction. ⋯ Various disease states may present specific considerations in the use of muscle relaxants. Although many complications of muscle relaxants (such as prolonged block or resistance) are easily treated, others may require immediate intervention and vigorous therapy. Careful selection of appropriate relaxants for particular patients will usually prevent the occurrence of complications.
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Review
Reducing chemotherapy-induced nausea and vomiting. Current perspectives and future possibilities.
Nausea and vomiting are among the most distressing adverse effects of cancer chemotherapy. In the last 10 years considerable advances in the prevention of chemotherapy-induced emesis have been made. From an analysis of the results obtained in patients receiving moderately- to severely-emetogenic drugs the following guidelines in choosing the best antiemetic treatment can be given: 1. ⋯ Although equally efficacious, the serotonin (5-HT)3 receptor antagonists, due to their higher acquisition costs, are indicated only in patients refractory to corticosteroids or in those who cannot use them. Unresolved problems in antiemetic research include: (i) identification of the best antiemetic treatment for those areas of cancer chemotherapy where adequate data are lacking, such as high dose regimens for bone marrow transplantation; (ii) optimisation of treatment for the most widely used chemotherapy regimens; and (iii) identification of the best rescue treatment for patients who fail to respond to antiemetic prophylaxis. Although many new 5-HT3 antagonists are currently being studied, the possible improvement in efficacy and tolerability brought about by these agents will probably only be marginal.
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Despite a continuous search for safer and more immunogenic vaccines, adverse reactions still occur. Adverse reactions to vaccines are generally mild; severe events resulting in death or permanent damage are rare. In every instance, the benefits of preventing the disease far outweigh the risks of vaccination. ⋯ Risk-benefit analyses for immunisation are faced with a number of potential difficulties; definition of the risks and benefits themselves, individual versus community risks and benefits, and the continuously evolving nature of risks with changes in disease epidemiology. Based on risk-benefit studies, for an individual just as for the community, it may not always be of interest to use the vaccine with the lowest complication rate. Good immunisation programmes should help to decrease the risk of adverse effects.
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Opioid analgesics and other drugs interact through multiple mechanisms, resulting in pharmacological effects that depend upon the pharmacodynamic action studied, the interacting agents and the route of administration. Many interactions result from induction or inhibition of the hepatic cytochrome P450 mono-oxygenase system. The elimination of opioids is largely dependent on hepatic metabolism, and drug interactions involving this mechanism can therefore be clinically significant. ⋯ Such interactions are manifested clinically as as a summation (additive or synergistic) of similar or opposing pharmacological effects on the same body system. Idiosyncratic interactions also occur, the mechanisms of which have not been proven to be solely modulated by either pharmacokinetic or pharmacodynamic means. The knowledge of particular opioid-drug interactions, and the causative pharmacokinetic, pharmacodynamic, and idiosyncratic mechanisms, allows for the safer administration of opioid analgesics.