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Dosage Adjustment (dosage + adjustment)

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Medical Sciences	87%

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Effects of woohwangcheongsimwon suspension on the pharmacokinetics of bupropion and its active metabolite, 4-hydroxybupropion, in healthy subjects

BRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 1 2010
Hyunmi Kim
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT , Woohwangcheongsimwon suspension has traditionally been used for the treatment and prevention of stroke, hypertension, palpitations, convulsions and unconsciousness in various Asian countries. , Woohwangcheongsimwon suspensions showed an inhibitory effect on CYP2B6 activity in vitro. Two terpenoids, borneol and isoborneol, are major constituents of woohwangcheongsimwon suspension, and show a competitive inhibition of CYP2B6 with Ki values of 9.5 and 5.9 µm, respectively. , Bupropion undergoes metabolic transformation to the active metabolite, 4-hydroxybupropion, primarily via CYP2B6 both in vivo and in vitro. It is often used as a CYP2B6 substrate for clinical drug,drug interaction studies. , Drug interactions may occur between woohwangcheongsimwon suspension and bupropion. WHAT THIS STUDY ADDS , Co-administration with woohwangcheongsimwon suspension did not alter the pharmacokinetics of bupropion or its metabolite, 4-hydroxybupropion. , Dosage adjustment of bupropion is unnecessary in patients concomitantly administered the highest recommended daily dose of woohwangcheongsimwon suspension. AIMS To examine the effects of woohwangcheongsimwon suspension on the pharmacokinetics of bupropion and its active metabolite, 4-hydroxybupropion, formed via CYP2B6 in vivo. METHODS A two-way crossover clinical trial with a 2 week washout period was conducted in 14 healthy volunteers. In phases I and II, subjects received 150 mg bupropion with or without woohwangcheongsimwon suspension four times (at ,0.17, 3.5, 23.5 and 47.5 h, with the time of bupropion administration taken as 0 h) in a randomized balanced crossover order. Bupropion and 4-hydroxybupropion plasma concentrations were measured for up to 72 h by LC-MS/MS. Urine was collected up to 24 h to calculate the renal clearance. In addition, the CYP2B6*6 genotype was also analyzed. RESULTS The geometric mean ratios and 90% confidence interval of bupropion with woohwangcheongsimwon suspension relative to bupropion alone were 0.976 (0.917, 1.04) for AUC(0,,) and 0.948 (0.830,1.08) for Cmax, respectively. The corresponding values for 4-hydroxybupropion were 0.856 (0.802, 0.912) and 0.845 (0.782, 0.914), respectively. The tmax values of bupropion and 4-hydroxybupropion were not significantly different between the two groups (P > 0.05). The pharmacokinetic parameters of bupropion and 4-hydroxybupropion were unaffected by woohwangcheongsimwon suspension. CONCLUSIONS These results indicate that woohwangcheongsimwon suspension has a negligible effect on the disposition of a single dose of bupropion in vivo. As a result, temporary co-administration with woohwangcheongsimwon suspension does not seem to require a dosage adjustment of bupropion. [source]

Clinical Pharmacokinetics of Frovatriptan

HEADACHE, Issue 2002
P. Buchan PhD
Objective.,To review available data on the clinical pharmacokinetics of frovatriptan. Background.,Preclinical data suggest that the pharmacokinetic profile of frovatriptan may differ from that of the currently available triptans. Methods.,Studies of healthy volunteers, subjects with renal or hepatic impairment, elderly subjects, and patients with migraine during and between attacks were reviewed. Results.,Oral bioavailability of frovatriptan is 22% to 30%, and although the time to maximum concentration is typically 2 to 3 hours, approximately 60% to 70% of plasma maximum concentration is achieved within 1 hour of dosing. Frovatriptan distributes into erythrocytes, with binding reversible and time dependent. The relatively long terminal elimination half-life (about 26 hours) confers good systemic exposure and may produce a long duration of therapeutic action, thus reducing migraine recurrence and the need for redosing. Systemic exposure to frovatriptan generally correlates with dose between 1 and 100 mg. Blood and plasma frovatriptan concentrations are consistently higher in females, but there is no need to adjust dose according to gender. Pharmacokinetics are essentially unaffected by food and were predictable after repeat dosing; steady state is approached in about 4 to 5 days. Pharmacokinetics were changed only slightly in subjects with renal impairment or mild-to-moderate hepatic impairment, elderly individuals, and during migraine attacks. Frovatriptan is principally metabolized by the CYP1A2 isoenzyme of cytochrome P-450 and is cleared by the kidney and liver, each having sufficient capacity to compensate for impairment of the other. Conclusions.,Frovatriptan can be taken without regard for food intake, and because of the large therapeutic margin and shallow dose-response curve, there is no need for dosage adjustment in the elderly, in women taking a combined oral contraceptive, in patients with mild-to-severe renal impairment, mild-to-moderate hepatic impairment, or according to gender. The long duration of exposure may reduce the likelihood of early migraine recurrence. [source]

Clinically relevant drug interactions of current antifungal agents

MYCOSES, Issue 2 2010
Paul O. Gubbins
Summary Antifungal agents are often prescribed in critically ill patients who are receiving many other medications. When using systemic antifungals, clinicians may possess susceptibility data and they are typically aware of the potential toxicity of these agents. However, the myriad of potential drugs that antifungal agents can interact with is daunting and can be confusing. This article reviews the pharmacokinetic properties of antifungal agents and their clinically relevant drug interactions. The antifungal agents differ markedly in their pharmacokinetic properties and in how they interact with other medicines. The amphotericin B formulations interact with other medicines primarily by reducing their renal elimination or producing additive toxicities. The azoles interact with other medicines primarily by inhibiting biotransformation or by affecting drug distribution and elimination. The echinocandins have the lowest propensity to interact with other medicines. The clinical relevance of antifungal,drug interactions varies substantially. While certain interactions are benign and result in little or no untoward clinical outcomes, others can produce significant toxicity or compromise efficacy if not properly managed through monitoring and dosage adjustment. However, certain interactions produce significant toxicity or compromise efficacy to such an extent that they cannot be managed and the particular combination of antifungal and interacting medicine should be avoided. [source]

Potential impact of a new blood glucose monitoring device: the GlucoWatch® Biographer

PRACTICAL DIABETES INTERNATIONAL (INCORPORATING CARDIABETES), Issue 4 2002
NN Chan
Abstract Home blood glucose monitoring may be laborious, time-consuming, inconvenient and painful. Failure to test may preclude optimisation of glycaemic control. We aimed to evaluate the potential usefulness of a new noninvasive automatic glucose monitor, the GlucoWatch® Biographer. Eight patients with type 1 diabetes and two with type 2 diabetes (4M:6F) aged between 23 and 65 years participated in this study. All participants were given 1 hour of instruction prior to provision of the GlucoWatch®. They were given contact numbers and reviewed weekly. Several disadvantages were encountered by the participants, which included the daily 3 hour calibration period (n = 10), skin irritations (n = 6) and skipped measurements (n = 2) due to unsatisfactory probe contact due to skin temperature or sweats. Several patients, however, found it invaluable to have their daily profile monitored to allow insulin dosage adjustment and detection of hypoglycaemia. The GlucoWatch® Biographer is an invaluable tool that allows noninvasive detection of glucose trends, which contributes to glycaemic control. However, it is not suitable for every patient. Self-motivation and ability to learn how to use the device are the key factors. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Long-term efficacy of the interleukin-1 receptor antagonist anakinra in ten patients with neonatal-onset multisystem inflammatory disease/chronic infantile neurologic, cutaneous, articular syndrome

ARTHRITIS & RHEUMATISM, Issue 1 2010
Bénédicte Neven
Objective Cryopyrin-associated periodic syndromes (CAPS) are a group of rare autoinflammatory diseases. Neonatal-onset multisystem inflammatory disease (NOMID)/chronic infantile neurologic, cutaneous, articular syndrome (CINCA syndrome) is the most severe phenotype, with fever, rash, articular manifestations, and neurologic and neurosensory involvement. CAPS are caused by mutations in CIAS1, the gene encoding NLRP3, which plays a critical role in interleukin-1 (IL-1) processing. Anakinra, an IL-1 receptor antagonist, has been shown to be an effective treatment; however, data on long-term efficacy and safety have been sparse. This study was undertaken to assess the long-term efficacy and safety of anakinra treatment in patients with NOMID/CINCA syndrome. Methods We retrospectively analyzed the medical records of NOMID/CINCA syndrome patients referred to 2 centers, who had started anakinra treatment before June 2007. Results There were 10 patients with NOMID/CINCA syndrome who had been treated with anakinra. The patients' ages at the time anakinra treatment was initiated ranged from 3 months to 20 years. They had been followed up for 26,42 months. Sustained efficacy in the treatment of systemic inflammation and, in some cases, neurologic involvement and growth parameters, was achieved. The dosage of anakinra required for efficacy ranged from 1 to 3 mg/kg/day in the 8 oldest patients and from 6 to 10 mg/kg/day in the 2 youngest. Residual central nervous system inflammation and deafness persisted in some patients, especially if there had been a delay in diagnosis and treatment. Secondary amyloidosis persisted in cases in which it was present at treatment initiation, but no new lesions developed. No effect on overgrowth arthropathy was observed. Adverse events consisted of mild injection-site reactions. Conclusion The present results indicate that anakinra treatment is effective over the long term in NOMID/CINCA syndrome. However, treatment has to be initiated before irreversible lesions develop, and, particularly in very young patients, dosage adjustment is required. [source]

Effects of woohwangcheongsimwon suspension on the pharmacokinetics of bupropion and its active metabolite, 4-hydroxybupropion, in healthy subjects

Pharmacokinetic interaction study between eslicarbazepine acetate and lamotrigine in healthy subjects

ACTA NEUROLOGICA SCANDINAVICA, Issue 4 2010
L. Almeida
Almeida L, Nunes T, Sicard E, Rocha J-F, Falcão A, Brunet J-S, Lefebvre M, Soares-da-Silva P. Pharmacokinetic interaction study between eslicarbazepine acetate and lamotrigine in healthy subjects. Acta Neurol Scand: 2010: 121: 257,264. © 2009 The Authors Journal compilation © 2009 Blackwell Munksgaard. Objective,,, Anti-epileptic drugs are often used in combination. Both eslicarbazepine (main metabolite of eslicarbazepine acetate, ESL) and lamotrigine undergo conjugation with glucuronic acid, and both eslicarbazepine and its glucuronide and lamotrigine glucuronide undergo extensive renal elimination; therefore, there is a potential for interaction. This study investigated the interaction between ESL and lamotrigine in healthy subjects. Methods,,, Open-label study in two parallel groups of 16 healthy volunteers each. After an 8-day treatment with ESL or lamotrigine, ESL (1200 mg once-daily) and lamotrigine (150 mg once-daily) were co-administered for 19 days. Geometric mean ratios (GMR) and 90% confidence intervals (90% CI) for maximum plasma concentration (Cmax) and area under the plasma concentration,time curve in the dosing interval (AUC0,24) were calculated for eslicarbazepine (ESL active metabolite) and lamotrigine. Results,,, The Cmax and AUC0,24 GMR (90% CI) were, respectively, 95% (87,102%) and 96% (91,102%) for eslicarbazepine, and 88% (82,94%) and 86% (81,92%) for lamotrigine. The 90% CI of the Cmax and AUC0,24 GMR fell within the prespecified acceptance interval (80,125%) both for eslicarbazepine and lamotrigine. Conclusion,,, There was no significant pharmacokinetic interaction between ESL and lamotrigine in healthy subjects. Therefore, no dosage adjustment appears to be usually required in either lamotrigine or ESL when the drugs are co-administered. [source]

Differential pharmacological regulation of drug efflux and pharmacoresistant schizophrenia

BIOESSAYS, Issue 2 2008
Mary Bebawy
Pharmacoresistant schizophrenia is a significant impediment to the successful management of the disease. The expression and function of P-glycoprotein (P-gp) has recently been implicated in this phenomenon. P-gp is a multidrug efflux transporter that prevents drug substrates from crossing the blood,brain barrier (BBB). Although the direct interaction between individual antipsychotic agents and P-gp has been demonstrated, the effect of antipsychotic drug combinations used in disease management on P-gp transport function remains to be elucidated. This could have important clinical implications in some individuals as dosage adjustments based on plasma drug concentration changes may not always be appropriate if drug,drug interactions and the resulting changes in drug concentration in the brain are not considered. This paper introduces the potential impact that combination antipsychotic therapy may have on P-gp function at the BBB and discusses the consequences of this in the prevention and circumvention of unfavourable therapeutic response in schizophrenic disorders. BioEssays 30:183,188, 2008. © 2008 Wiley Periodicals, Inc. [source]