Expert opinion on drug metabolism & toxicology
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Expert Opin Drug Metab Toxicol · Mar 2014
ReviewOndansetron: a review of pharmacokinetics and clinical experience in postoperative nausea and vomiting.
Postoperative nausea and vomiting (PONV) is associated with poor patient satisfaction and delayed recovery after general anesthesia. Multiple neurotransmitters are involved in the mediation of PONV but despite the introduction of new antiemetics, no completely effective drug exists for its prevention or treatment. ⋯ According to current literature, administering ondansetron 4 mg i.v. near the end of surgery provides sufficient protection against PONV in low- and moderate-risk patients, comparable to traditional antiemetics such as antihistamines and droperidol. High-risk patients require a multimodal approach since one quarter of them will not respond to monotherapy. In the future, transdermal formulation or formulations for nasal or buccal delivery will be available. The development of non-racemic mixture consisting of R-ondansetron would enhance the safety profile and probably the efficacy too.
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Expert Opin Drug Metab Toxicol · Feb 2014
ReviewPharmacokinetic and pharmacodynamic modeling for acute and chronic pain drug assessment.
Population pharmacokinetic and pharmacodynamic (PK/PD) modeling is a critical component of drug development. Quantitative PK/PD models are used in drug development to improve both the design and interpretation of clinical trials across therapeutic areas. ⋯ New modeling approaches suitable for analgesics used in treatment of acute and chronic pain have started to emerge during the past few years. The application of the clinical utility index is limited but highly encouraged in pain drug assessment as it may inform the optimal window for treatment of pain to attain the best benefit:risk ratio. Owing to the restricted range of pain scores, beta regression models and coarsening models may be more appropriate modeling approaches for the bounded outcome data, rather than regular nonlinear/linear models that assume normal or lognormal error distribution. Additionally, modeling of exposure-response in flexible chronic pain studies remains challenging, and further investigations are needed.
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Expert Opin Drug Metab Toxicol · Sep 2013
ReviewPharmacokinetic evaluation of nabiximols for the treatment of multiple sclerosis pain.
Pain associated with multiple sclerosis (MS) is frequent, and frequently not alleviated by currently available drugs. Nabiximols is a combination of two plant cannabinoids administered via an oromucosal pump spray and approved in Canada for the treatment of intractable central neuropathic pain due to MS and intractable cancer pain. Nabiximols exerts its analgesic effects through its interaction with the endocannabinoid system to modulate pain transmission via pain networks. ⋯ Nabiximols is an appropriate therapy for pain patients who tend to be particularly resistant to pharmacological interventions. Its action depends on not only the local constellation of the endocannabinoid system signalling, but also the particular functional status of pain pathways and on the specific mechanism of neuropathic pain. It is therefore justifiable that further studies are initiated which aim to define the best responder profile and which explore the full potential of nabiximols in MS-related pain.
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Expert Opin Drug Metab Toxicol · Sep 2013
ReviewDrug absorption, distribution, metabolism and excretion considerations in critically ill adults.
All critically ill patients require medication to treat organ dysfunction. However, the pharmacokinetics of drugs used to treat these patients is complex due to frequent alterations in drug absorption, distribution, metabolism, and excretion (ADME). ⋯ Dosage pharmacokinetics determined from single-dose or limited-duration administration studies in healthy volunteers may not apply to critically ill patients. Organ dysfunction among these patients may be due to pre-existing disease or the effects of a systemic or locoregional inflammatory response precipitated by their illness. Alterations in pharmacokinetics observed among the critically ill include altered bioavailability after enteral administration, increased volume of distribution and blood-brain barrier permeability and changes in P-glycoprotein and cytochrome P450 enzyme function. However, the effect of these changes on clinically important outcomes remains uncertain and poorly studied. Future investigations should examine not only pharmacokinetic changes among the critically ill, but also whether recognition of these changes and alterations in drug therapy directed as a consequence of their observation alters patient outcomes.
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Expert Opin Drug Metab Toxicol · Aug 2013
ReviewPharmacokinetic evaluation of teriflunomide for the treatment of multiple sclerosis.
Teriflunomide is an immunomodulatory drug that received FDA approval for the treatment of relapsing forms of multiple sclerosis (MS) in September 2012. Its primary mode of action is inhibition of dihydroorotate dehydrogenase which inhibits the proliferation of activated T cells, but it also has a number of other actions that may be important contributors to its efficacy in MS. ⋯ While teriflunomide is no more effective than a number of other agents that are used in the treatment of MS, it has a favorable side-effect profile and the convenience of once a day oral administration. As such, it is likely to be a popular agent in the treatment of MS over the next 5 years.