Long-term efficacy and safety of once-daily fosamprenavir 1400 mg boosted by ritonavir 100 mg: the BOLD100 study.

In a retrospective database study at two HIV treatment centres, medical records were accessed to evaluate long-term efficacy and safety parameters in all HIV-infected adults who had achieved HIV-1 RNA <50 copies/mL following the initiation of fosamprenavir (FPV)/ritonavir (RTV) 1400 mg/100 mg once-daily (QD)-containing regimens between January 2004 and January 2006. Data were available for 20 antiretroviral (ARV)-naïve patients (baseline median HIV-1 RNA 5.0 log(10) copies/mL; CD4+ cell count 307 cells/mm(3)), 30 protease inhibitor (PI)-naïve, ARV-experienced patients (HIV-1 RNA 3.6 log(10) copies/mL; CD4+ count 348 cells/mm(3)) and 25 PI-experienced patients switching to FPV/RTV100 for reasons other than virological failure (HIV-1 RNA 2.7 log(10) copies/mL; CD4+ count 328 cells/mm(3)). HIV-1 RNA <50 copies/mL was achieved in 100% of the ARV-naïve cohort (median monitoring period, 2.4 years; range, 1.4-3.2 years), 87% of the PI-naïve cohort (2.4 years; range, 1.2-3.4 years) and 88% of the PI-experienced cohort (2.2 years; range, 1.0-3.2 years). Virological failure occurred in 0%, 7% and 8% of the cohorts, respectively, and median CD4+ count increased above baseline by 224, 155 and 115 cells/mm(3), respectively. Change from baseline in median fasting lipids was: total cholesterol +12, -6, -2 mg/dL; low-density lipoprotein-cholesterol 0, -5, +12 mg/dL; high-density lipoprotein-cholesterol +4, +2, +7 mg/dL; triglycerides +9, -21, -65 mg/dL, respectively. In conclusion, FPV/RTV 1400/100 mg QD-containing regimens remained effective long-term in all ARV-naïve and most PI-naïve and PI-experienced HIV-infected patients.

Accelerator mass spectrometry measurement of intracellular concentrations of active drug metabolites in human target cells in vivo.

Accelerator mass spectrometry (AMS) is an ultrasensitive technique to detect radiolabeled compounds. We administered a microdose (100 µg) of (14)C-labeled zidovudine (ZDV) with or without a standard unlabeled dose (300 mg) to healthy volunteers. Intracellular ZDV-triphosphate (ZDV-TP) concentration was measured using AMS and liquid chromatography-tandem mass spectrometry (LC/MS/MS). AMS analysis yielded excellent concordance with LC/MS/MS and was 30,000-fold more sensitive. The kinetics of intracellular ZDV-TP formation changed several-fold over the dose range studied (100 µg-300 mg). AMS holds promise as a tool for quantifying intracellular drug metabolites and other biomediators in vivo.

Steady-state amprenavir and tenofovir pharmacokinetics after coadministration of unboosted or ritonavir-boosted fosamprenavir with tenofovir disoproxil fumarate in healthy volunteers.

Objective An open-label, three-period pharmacokinetic study was conducted to investigate the drug interaction potential between fosamprenavir (FPV) and tenofovir disoproxil fumarate (TDF). Methods Thirty-six healthy subjects received TDF 300 mg once daily (qd) for 7 days (period 1), and then were randomized to 14 days of either FPV 1400 mg twice daily (bid) or FPV/ritonavir (RTV) 700/100 mg bid alone or with TDF (period 2). Subjects continued their randomized dose of FPV for 14 more days, adding or removing TDF based upon its receipt in period 2 (period 3). Twenty-four-hour pharmacokinetic sampling was carried out on day 7 of period 1 and on day 14 of periods 2 and 3. Steady-state plasma amprenavir (APV) and tenofovir (TFV) pharmacokinetics were assessed by noncompartmental analysis and parameter values observed with each regimen were compared using geometric mean ratios with 90% confidence intervals. Results After TDF coadministration, APV geometric mean minimum concentration (C(min)), maximum concentration (C(max)), and area under the plasma concentration-time curve (AUC) increased by 31, 3 and 7% above values observed with unboosted FPV alone; they also increased by 31, 4 and 16% above values observed with FPV/RTV alone. TFV C(min), C(max) and AUC decreased by 12, 25 and 15% after FPV coadministration and by 9, 18 and 7% after FPV/RTV coadministration. No significant changes in RTV pharmacokinetics were observed. No differences were noted in adverse events among dosing periods. Conclusions In this evaluation of the interaction between FPV and TDF, increases in APV exposures and modest decreases in TFV exposures were observed. These were unlikely to be clinically significant.

Abacavir pharmacokinetics during chronic therapy in HIV-1-infected adolescents and young adults.

The pharmacokinetics of abacavir and its metabolites were investigated in 30 human immunodeficiency virus (HIV)-infected adolescents and young adults 13-25 years of age, equally divided into two groups: <18 years of age and >or=18 years of age. All the subjects received the recommended adult dose of 300 mg twice daily. The area under the plasma concentration-time curve (AUC) and half-life of abacavir did not differ significantly between the age groups or by gender or race, and there were only modest associations of age with apparent abacavir clearance and with volume of distribution. There were no significant correlations of carboxylate or glucuronide metabolite levels with age or gender, although glucuronide AUC was higher in Hispanic subjects than in African-American subjects. Zidovudine and lamivudine concentration profiles were also similar in the two age groups. A novel aspect of the study included an assessment of intracellular carbovir, zidovudine, and lamivudine triphosphate levels, and these were found to be similar in the two age-based groups. Overall, these findings suggest that current recommendations relating to adult dosages are appropriate for adolescents and young adults.

A prospective, 96-week study of the impact of Trizivir, Combivir/nelfinavir, and lamivudine/stavudine/nelfinavir on lipids, metabolic parameters and efficacy in antiretroviral-naive patients: effect of sex and ethnicity.

OBJECTIVES: To compare the lipid and metabolic effects, efficacy, and safety of twice-daily regimens of Trizivir (abacavir 300 mg/lamivudine 150 mg/zidovudine 300 mg triple nucleoside tablet; TZV), Combivir (lamivudine 150 mg/zidovudine 300 mg combination tablet; COM)+nelfinavir (NFV), and stavudine (d4 T)+lamivudine (3TC)+NFV. STUDY DESIGN: An international, phase 4, open-label, parallel-group, 34-centre study was conducted in 254 non-diabetic, antiretroviral-naive, HIV-infected out-patients with an HIV-1 RNA level of >1000 HIV-1 RNA copies/mL and < or =200,000 copies/mL and a CD4 cell count of >50 cells/microL. METHODS: Patients were randomized 1 : 1 : 1 to TZV twice daily (n = 85), COM/NFV 1250 mg twice daily (n = 88), or d4T 40 mg+3TC 150 mg+NFV 1250 mg twice daily (n = 81) for 96 weeks. Treatments were compared using analysis of covariance (ANCOVA) with regard to changes from baseline in fasting lipids in the total population and in sex and ethnic subgroups. The proportions of patients achieving HIV-1 RNA <50 and <400 copies/mL were compared using a 95% confidence interval (CI) on the difference between proportions. RESULTS: The study population was diverse (50% female, 40% black and 37% Hispanic). Mean baseline low-density lipoprotein (LDL) cholesterol was 99 mg/dL, HIV-1 RNA was 4.43 log10 copies/mL and CD4 cell count was 355 cells/microL. At week 96, fasting LDL cholesterol changed minimally in the TZV group [least square mean (LSM) change from baseline, -8 mg/dL], but increased with d4T/3TC/NFV and COM/NFV (+29 and +19 mg/dL, respectively; P < 0.001 versus TZV). Week 96 LDL-cholesterol levels were significantly lower in the TZV group than in the other two treatment groups in women and men and lower than in the d4T/3TC/NFV group in Hispanic and black patients. In black patients, the week-96 LSM change from baseline in LDL cholesterol was significantly less with TZV than with d4T/3TC/NFV (+1 vs+39 mg/dL; P = 0.003). Total cholesterol >200 mg/dL occurred in a smaller proportion of patients receiving TZV (30%) compared with COM/NFV (50%) or d4T/3TC/NFV (60%; P = 0.005 vs TZV). High-density lipoprotein (HDL) cholesterol did not change markedly with any treatment. Although triglycerides increased, they changed least in women and Hispanic patients receiving TZV. Virological and CD4 responses to the treatments were similar in the total population and in the subgroups. Diarrhoea was reported more often in the NFV arms and nausea in the ZDV arms. CONCLUSIONS: Over 96 weeks, TZV twice daily has significantly less effect on LDL cholesterol than COM/NFV or d4T/3TC/NFV twice daily, especially in women and black patients, and is associated with similar virological and CD4 responses.

Correlation between self-reported adherence to highly active antiretroviral therapy (HAART) and virologic outcome.

The Patient Medication Adherence Questionnaire Version 1.0 (PMAQ-V1.0) is a patient-reported adherence instrument to assess medication-taking behaviors and identify barriers to adherence with antiretroviral therapy. To assess the correlation between adherence and virologic outcome, the PMAQ-V1.0 was administered to 194 antiretroviral-experienced adults with HIV infection enrolled in a 16-week evaluation of protease inhibitor-containing regimens featuring a lamivudine/zidovudine combination tablet. At baseline, plasma HIV-1 RNA levels were less than 10,000 copies/mL and CD4(+)-cell counts were equal to or greater than 300 x 10(6)/L; patients had been receiving a conventional regimen of lamivudine + zidovudine (separately) plus a protease inhibitor for at least 10 weeks immediately prior to the study. Forty-eight percent of patients who reported missing at least one dose of a nucleoside reverse-transcriptase inhibitor (NRTI) during the study had detectable plasma HIV-1 RNA, compared with 26% of patients who reported no missed doses (P = .002). Patients who missed at least one dose of an NRTI or protease inhibitor were 2.5 times more likely to have quantifiable HIV-1 RNA than those who reported no missed doses. Patients who reported fewer barriers and more motivators to adherence had better virologic outcomes (P = .001). Several dimensions of the PMAQ-V1.0 did not function as well as hypothesized. In this study, self-reported adherence derived from the PMAQ-V1.0 predicted virologic outcomes, but further refinement of the dimensions appears warranted.

Pharmacokinetics of zidovudine and lamivudine in neonates following coadministration of oral doses every 12 hours.

A phase I, repeat-dose, open-label study was conducted to determine the pharmacokinetics and safety of zidovudine and lamivudine, coadministered orally every 12 hours, in 16 neonates whose mothers were infected with human immunodeficiency virus type 1 (HIV-1). The prospective mothers had been stabilized on a zidovudine/lamivudine regimen since week 36 of pregnancy to prevent mother-to-child transmission of HIV. During 1 week postpartum, the mothers received zidovudine 300 mg plus lamivudine 150 mg every 12 hours and breastfed. Neonatal treatment was initiated 12 hours following birth with 4 mg/kg of zidovudine suspension plus 2 mg/kg of lamivudine solution every 12 hours; this regimen was continued for 1 week. Between days 1 and 7 of neonatal treatment, the neonatal oral clearance (CL/F) of zidovudine and lamivudine increased by 2-fold (p < 0.001) and 1.6-fold (p = 0.004), respectively, possibly reflecting maturation of intestinal hepatic and renal function occurring during the first week of life. Day 7/day 1 ratios for exposure (area under the serum concentration-time curve [AUC]) and maximum observed serum concentration (Cmax) were 0.48 and 0.63, respectively, for zidovudine and 0.64 and 0.73, respectively, for lamivudine. At the time of delivery, the geometric mean cord/maternal concentration ratio was 1.24 for zidovudine and 1.12 for lamivudine, indicating free passage of each drug across the placenta. The maternal and neonatal treatment regimens were well tolerated. The results of this study confirm that in the neonate, a convenient regimen combining zidovudine 4 mg/kg and lamivudine 2 mg/kg, administered orally every 12 hours, provides zidovudine serum exposure very similar to that reported with the standard neonatal zidovudine regimen of 2 mg/kg every 6 hours, as well as lamivudine serum exposure within the range reported in adults receiving lamivudine 150 mg twice a day and children receiving 4 mg/kg twice a day.

Writing manuscripts describing clinical trials: a guide for pharmacotherapeutic researchers.

Once researchers have completed a clinical trial and analyzed the data, they have a duty to make the results known to their peers by writing a manuscript suitable for publication in a biomedical journal. Before beginning any writing, those involved in the clinical drug trial first need to decide among themselves who is to be the first author and secondary authors, the readership they want to influence, and the most appropriate target journal to reach this readership. For content and formatting of the manuscript, writers need to carefully follow the instructions for authors as stipulated by the target journal. In general, a manuscript based on a clinical trial is presented sequentially in four sections: Introduction, Methods, Results, and Discussion (IMRAD). The introduction concisely presents background information about the topic that was researched in the clinical trial, provides the study hypothesis, and describes the study rationale, purpose, and objectives. The Methods section delineates the study design, subject/patient selection process, procedures, end points, and types of analysis conducted in the clinical trial to investigate the study hypothesis. The Results section presents the findings of the clinical trial, and the Discussion section interprets the meaning of these findings, assesses how the findings answer the study hypothesis, and compares the study data with findings reported in earlier studies. Writers should select a title for the clinical trial manuscript that is fewer than 10 words and which embodies the essence of the study findings clearly and specifically without being sensationalistic. Writers should create the abstract last; the abstract should provide an overview of the manuscript and stimulate readers' interest. Overall, following the above principles in writing a manuscript based on a clinical drug trial will make the actual writing easier and more enjoyable, as well as increase the possibility of the manuscript being accepted for publication.

Population pharmacokinetics of lamivudine in adult human immunodeficiency virus-infected patients enrolled in two phase III clinical trials.

Lamivudine population pharmacokinetics were investigated by using nonlinear mixed-effect modelling (NONMEM) analysis of data from 394 human immunodeficiency virus (HIV)-infected patients treated with lamivudine (150 to 300 mg every 12 h) in two large, phase III clinical efficacy-safety trials, NUCA3001 and NUCA3002. Analyses of 1,477 serum lamivudine concentration determinations showed that population estimates for lamivudine oral clearance (CL/F; 25.1 liters/h) and volume of distribution (V/F; 128 liters) were similar to values previously reported for HIV-infected patients in phase I pharmacokinetic studies. Lamivudine CL/F was significantly influenced by the covariates creatinine clearance and weight and not affected by age, Centers for Disease Control and Prevention (CDC) classification, CD4(+) cell count, HIV type 1 (HIV-1) RNA PCR, or gender and race when CL/F was corrected for differences in patient weight. The population estimate for lamivudine V/F was not significantly influenced by the covariates gender, race, age, weight, renal function, HIV-1 RNA PCR, or CDC classification and CD4(+) cell count when creatinine clearance was included with CL/F in the model. Lamivudine disposition was significantly influenced by renal function. However, as only three patients had an estimated creatinine clearance of <60 ml/min, dosage adjustments for patients with impaired renal function should not be determined based on the population parameters derived in this analysis.

The pharmacokinetics of lamivudine phosphorylation in peripheral blood mononuclear cells from patients infected with HIV-1.

OBJECTIVE: To assess the pharmacokinetics of lamivudine phosphorylation in peripheral blood mononuclear cells (PBMC) from patients infected with HIV-1. DESIGN: Single-center, open-label, randomized, two-period, cross-over study in 10 asymptomatic, antiretroviral-experienced, HIV-1-infected patients who had a CD4+ lymphocyte count of 200-500 x 10(6)/l and had received combination treatment with lamivudine 150 mg twice a day plus zidovudine 600 mg a day (divided into two or three doses) for > or = 16 weeks prior to study entry. METHODS: Patients were randomly assigned to receive lamivudine 150 mg twice a day or lamivudine 300 mg twice a day for 14 days, with at least a 48-h washout period between treatments. Serial blood samples were collected over 36 h for determination of lamivudine serum concentrations using liquid chromatography/mass spectrometry and intracellular phosphate PBMC concentrations using high performance liquid chromatography/radioimmunoassay methods. Pharmacokinetic parameters were calculated based on lamivudine and lamivudine anabolite concentration-time data. RESULTS: Intracellular pharmacokinetic parameters were highly variable between patients (coefficient of variations approximately 50%). The two regimens produced lamivudine-total phosphate (totP) values of a similar magnitude. Although the 300-mg regimen tended to produce higher lamivudine-monophosphate (MP) and -triphosphate (TP) values, differences from values produced by the 150-mg regimen were not statistically significant. As lamivudine diphosphate (DP) was the predominant anabolite, accounting for 50-55% of lamivudine-totP (compared with 30-35% for lamivudine-MP and 15-20% for lamivudine-TP), the conversion of lamivudine-DP to lamivudine-TP can be regarded as the rate-limiting step. The median lamivudine-TP intracellular half-life (t1/2) for the 150-mg and 300-mg regimens did not differ significantly (15.3 and 16.1 h, respectively). Serum lamivudine pharmacokinetic parameters were consistent with those observed in previous studies in HIV-1-infected patients. No apparent linear relationships were observed between lamivudine intracellular anabolite and serum data. CONCLUSIONS: The intracellular pharmacokinetics of lamivudine phosphorylation in PBMC from asymptomatic HIV-1-infected patients are highly variable and do not differ statistically between the 150- and 300-mg twice a day regimens. The variations in intracellular lamivudine-TP concentrations following these two lamivudine dosage regimens are unlikely to result in differences in clinical effect. This was confirmed by the results of a large phase III study in HIV-1-infected patients which showed no differences in HIV-1 RNA or CD4+ lymphocyte counts between the 150- and 300-mg lamivudine regimens in combination with zidovudine.

Lamivudine/zidovudine as a combined formulation tablet: bioequivalence compared with lamivudine and zidovudine administered concurrently and the effect of food on absorption.

A single-center, open-label, three-way crossover study was conducted in 24 healthy subjects to assess (1) the bioequivalence of a combined lamivudine 150 mg/zidovudine 300 mg tablet relative to the separate brand-name components administered concurrently and (2) the effect of food on the bioavailability of the drugs from the combination tablet. The subjects were randomly assigned to receive each of the following three treatments, separated by a 5- to 7-day washout period: one lamivudine/zidovudine combination tablet after an overnight fast, one lamivudine 150 mg tablet and one zidovudine 300 mg tablet simultaneously after an overnight fast, or one lamivudine/zidovudine combination tablet 5 minutes after completing a standardized high-fat breakfast (67 g fat, 58 g carbohydrate, and 33 g protein). Serial blood samples were collected up to 24 hours postdose for the determination of lamivudine and zidovudine plasma concentrations. Standard pharmacokinetic parameters were estimated. Treatments were considered bioequivalent if 90% confidence intervals for the ratio of least squares (LS) means for the lamivudine and zidovudine area under the plasma concentration-time curve (AUC infinity) and maximum observed plasma concentration (Cmax) fell entirely within 0.80 to 1.25 for log-transformed parameters. The combined lamivudine/zidovudine tablet was bioequivalent in the extent (AUC infinity) and rate of absorption (Cmax and time of Cmax [tmax]) to the individual brand-name drug components administered concurrently under fasted conditions. Geometric LS mean ratios and 90% confidence intervals for AUC infinity and Cmax were 0.97 (0.92, 1.03) and 0.94 (0.84, 1.06), respectively, for lamivudine and 0.99 (0.91, 1.07) and 0.97 (0.82, 1.15), respectively, for zidovudine. The extent of absorption of lamivudine and zidovudine from the combination tablet was not altered by administration with meals, indicating that this formulation may be administered with or without food. However, food slowed the rate of absorption, delayed the tmax, and reduced the Cmax of lamivudine and zidovudine. These changes were not considered clinically important. All formulations were well tolerated under fasted and fed conditions.

Clinical pharmacokinetics of lamivudine.

Lamivudine (3TC), the negative enantiomer of 2'-deoxy-3'-thiacytidine, is a dideoxynucleoside analogue used in combination with other agents in the treatment of human immunodeficiency virus type 1 (HIV-1) infection and as monotherapy in the treatment of hepatitis B virus (HBV) infection. Lamivudine undergoes anabolic phosphorylation by intracellular kinases to form lamivudine 5'-triphosphate, the active anabolite which prevents HIV-1 and HBV replication by competitively inhibiting viral reverse transcriptase and terminating proviral DNA chain extension. The pharmacokinetics of lamivudine are similar in patients with HIV-1 or HBV infection, and healthy volunteers. The drug is rapidly absorbed after oral administration, with maximum serum concentrations usually attained 0.5 to 1.5 hours after the dose. The absolute bioavailability is approximately 82 and 68% in adults and children, respectively. Lamivudine systemic exposure, as measured by the area under the serum drug concentration-time curve (AUC), is not altered when it is administered with food. Lamivudine is widely distributed into total body fluid, the mean apparent volume of distribution (Vd) being approximately 1.3 L/kg following intravenous administration. In pregnant women, lamivudine concentrations in maternal serum, amniotic fluid, umbilical cord and neonatal serum are comparable, indicating that the drug diffuses freely across the placenta. In postpartum women lamivudine is secreted into breast milk. The concentration of lamivudine in cerebrospinal fluid (CSF) is low to modest, being 4 to 8% of serum concentrations in adults and 9 to 17% of serum concentrations in children measured at 2 to 4 hours after the dose. In patients with normal renal function, about 5% of the parent compound is metabolised to the trans-sulphoxide metabolite, which is pharmacologically inactive. In patients with renal impairment, the amount of trans-sulphoxide metabolite recovered in the urine increases, presumably as a function of the decreased lamivudine elimination. As approximately 70% of an oral dose is eliminated renally as unchanged drug, the dose needs to be reduced in patients with renal insufficiency. Hepatic impairment does not affect the pharmacokinetics of lamivudine. Systemic clearance following single intravenous doses averages 20 to 25 L/h (approximately 0.3 L/h/kg). The dominant elimination half-life of lamivudine is approximately 5 to 7 hours, and the in vitro intracellular half-life of its active 5'-triphosphate anabolite is 10.5 to 15.5 hours and 17 to 19 hours in HIV-1 and HBV cell lines, respectively. Drug interaction studies have shown that trimethoprim increases the AUC and decreases the renal clearance of lamivudine, although lamivudine does not affect the disposition of trimethoprim. Other studies have demonstrated no significant interaction between lamivudine and zidovudine or between lamivudine and interferon-alpha-2b. There is limited potential for drug-drug interactions with compounds that are metabolised and/or highly protein bound.

Safety, tolerability, and pharmacokinetics of sumatriptan suppositories following single and multiple doses in healthy volunteers.

A suppository formulation of the 5HT1 agonist sumatriptan could prove an important therapeutic option in migraine patients who dislike or poorly tolerate injectable therapy and where oral tablet administration is unsuitable because of severe migraine-related vomiting. Two independent double-blind, randomized clinical studies were conducted to evaluate the safety, tolerability and pharmacokinetics of sumatriptan suppositories following ascending single doses (four different dose levels) and multiple doses. In the four-period, crossover, single-dose study, 24 healthy male subjects were randomized to receive a suppository containing 12.5, 25, 50, or 100 mg on separate occasions 3-14 days apart. The suppositories were generally well tolerated; transient asthenia, drowsiness, and headache were the most frequently reported adverse events, and these were not dose-related. Peak plasma concentrations (Cmax) of sumatriptan were proportional to dose from 25 to 100 mg; area under the plasma concentration-time curve (AUC infinity) values were proportional to dose except at the highest doses, when they were greater than those predicted from lower doses. For all doses, the tmax of sumatriptan occurred within 2.5 h, and the t1/2 was approximately 2 h. In the two-period, placebo-controlled, crossover, repeat-dose study, 12 healthy adult male subjects were randomized to receive either a 50-mg sumatriptan suppository or placebo suppository, administered rectally twice a day, for 11 doses (5 1/2 days). Adverse events were no more frequent with sumatriptan than with placebo, and stool guaiac, rectal examinations, and physical examinations remained normal. No significant differences were noted between Day 1 and Day 6 values in the AUC, Cmax, time of peak serum concentration (tmax), elimination half-life (t 1/2), fraction of the dose excreted in the urine (fe), or renal clearance (Clr) of sumatriptan or its pharmacologically inactive indole acetic acid metabolite. Serum metabolite concentrations were two to three-fold higher than corresponding sumatriptan concentrations. No clinically significant accumulation of sumatriptan or its metabolite occurred. Overall, these studies show that sumatriptan administration via a suppository formulation is well tolerated, allows rapid absorption of sumatriptan, results in sumatriptan Cmax values that are proportional to dose from 25 to 100 mg, and is not associated with accumulation of sumatriptan or its metabolite.

Safety, tolerability, and pharmacokinetics of sumatriptan in healthy subjects following ascending single intranasal doses and multiple intranasal doses.

The delivery of sumatriptan doses intranasally could add greater flexibility in the treatment of migraine than is possible with the currently available subcutaneous and oral sumatriptan preparations. Two independent double-blind, randomized, placebo-controlled clinical studies were conducted to evaluate the safety, tolerability and pharmacokinetics of intranasally administered sumatriptan following ascending single doses (three different dose levels) and multiple doses. In the four-way, crossover, ascending-dose study, 20 healthy female subjects were randomized to receive on separate occasions single intranasal spray doses of 5, 10, or 20 mg sumatriptan (as the hemisulphate salt) or placebo into one nostril. Adverse events were mild and consisted mainly of bitter taste at the back of the throat and events typical of sumatriptan administered by other routes (headache, lightheadedness and tingling). Area under the plasma sumatriptan concentration versus time curve (AUC infinity) and peak plasma concentration (Cmax) increased with the dose. Dose proportionality was demonstrated between 5 and 10 mg but not across the dose range 5-20 mg. Time to maximum plasma concentration (tmax) was variable due to multiple peaking. The elimination half-life (t1/2), approximately 2 h, was unaffected by the magnitude of dose. In the two-period, multiple-dose, crossover study, 12 healthy adult male and female subjects were randomized to receive either sumatriptan hemisulphate 20 mg or placebo, administered intranasally as a spray three times a day for 4 days. The two dosing periods were separated by 3 to 14 days. Multiple doses of sumatriptan were well tolerated, with no serious adverse events occurring or withdrawals due to adverse events. All patients reported a mild to moderate drug-related disturbance of taste. Nasal examinations remained normal, and olfactory function was unaffected. The AUC over the first 8 h following dosing (AUC8) and fraction of the dose excreted in the urine (fe; 6.2% vs 3.6%) were similar on Days 1 and 4. Day 4 values were significantly higher (p < or = 0.05) for Cmax (16.9 ng/ml vs 13.1 ng/ml), renal clearance (Clr; 19.0 l/h vs 14.2 l/h), and t1/2 (2.18 h vs 1.93 h), and shorter for tmax (0.88 h vs 1.75 h). Some accumulation (22%) occurred over the 4 days of dosing. Serum concentrations of the pharmacologically inactive indole acetic acid metabolite of sumatriptan were fourfold to fivefold higher than corresponding sumatriptan concentrations. Overall, these studies show that the sumatriptan intranasal spray formulation is well tolerated, allows rapid absorption of sumatriptan, and results in only a clinically insignificant degree of sumatriptan accumulation upon repeated dosing.

Ondansetron absorption in adults: effect of dosage form, food, and antacids.

Ondansetron is a competitive serotonin 5-HT3 receptor blocker that has proved useful in the prevention of emesis due to cisplatin and other cancer chemotherapeutic agents. In a randomized, open-label, crossover study in 24 healthy male subjects, the relative bioavailability of a single 8-mg tablet was compared with that of an 8-mg solution using the two one-sided t-tests. The tablet and solution formulations were bioequivalent, as confirmed by similarities in mean Cmax (26.3 vs 27.7 ng/mL), Tmax (1.79 vs 1.70 h), and AUC (166.0 vs 167.3 ng.h/mL) values. In another randomized, open-label, crossover study in 12 healthy male subjects, the bioavailability of an 8-mg ondansetron tablet administered 5 min after a standard meal was slightly but significantly greater than in fasted subjects, as indicated by comparative mean AUC values [201.4 ng.h/mL (fed) vs 172.5 ng.h/mL (fasted)]. Coadministration of a magnesium hydroxide/aluminum hydroxide antacid did not affect the bioavailability of the ondansetron tablet.

Cefuroxime axetil in the treatment of sinusitis. A review.

Cefuroxime axetil is a beta-lactamase-stable, second-generation, oral cephalosporin that penetrates sinus tissue in concentrations exceeding the MIC90 values (the minimum concentration of drug needed to inhibit the growth of 90% of an isolate of a particular microorganism) for pathogens most commonly associated with acute sinusitis, including Streptococcus pneumoniae and Haemophilus influenzae. A review of all clinical data published to date demonstrates that cefuroxime axetil has been evaluated in the treatment of acute sinusitis and acute exacerbations of chronic sinusitis ("acute-on-chronic sinusitis") in 18 clinical trials involving 1516 assessable patients. In 12 randomized, comparative trials, the rates of satisfactory clinical outcomes (cure or improvement, 79% to 100%) and bacteriologic eradication (84% to 100%) reported with the use of 250 mg of cefuroxime axetil twice daily were similar to those observed with the use of amoxicillin, amoxicillin/clavulanate potassium, cefaclor, cefadroxil, cefixime, clarithromycin, and doxycycline. In these comparisons, no antibiotic demonstrated any therapeutic advantages over cefuroxime axetil regarding time to symptom abatement. Cefuroxime axetil was at least as well tolerated as the other antibiotics. Overall, the role of cefuroxime axetil in the treatment of sinusitis appears to be as one of the broad-spectrum antibiotics that can be used for infections due to the most commonly implicated sinus pathogens, especially those due to the increasing number of relatively penicillin-resistant strains of S pneumoniae and beta-lactamase-producing strains of H influenzae and Moraxella catarrhalis.

Albuterol extended-release products: effect of food on the pharmacokinetics of single oral doses of Volmax and Proventil Repetabs in healthy male volunteers.

The absorption of albuterol from a single 4-mg oral dose of Volmax and Proventil Repetabs was investigated under both fasting and fed conditions in an open-label, randomized, four-period, crossover study in 24 healthy male volunteers. Blood was collected for determination of albuterol plasma concentrations by HPLC over 30 hours postdose. Twenty subjects were evaluable for data analysis. The mean Cmax for Volmax; administered after a meal was 19% lower than that of the drug administered in a fasting state (3.9 ng/mL vs. 4.8 ng/mL; P less than .01). An almost equivalent lowering of the mean Cmax (by 21%) was observed for Proventil Repetabs after administration with a meal versus fasting (4.2 ng/mL vs. 5.3 ng/mL; P less than .01). There were no significant differences between the two formulations in the degree of Cmax reduction due to the presence of food. The tmax occurred significantly later during the fed treatment for Volmax only (4.9 hours fasted vs. 6.4 hours fed; P less than .01). The lag time was significantly greater during the fed treatments for Volmax. No differences were observed in the area under the plasma concentration-time curve (AUC) for either formulation under fasting versus fed conditions, suggesting that the extent of absortion was not altered by food. Overall, food caused a more sustained release of albuterol from both Volmax and Proventil Repetabs.

Oxiconazole nitrate: pharmacology, efficacy, and safety of a new imidazole antifungal agent.

Oxiconazole nitrate (1%) cream became available in the United States in 1989 for the once-daily treatment of tinea pedis, tinea cruris, and tinea corporis. It has also proved valuable in the once-daily treatment of tinea (pityriasis) versicolor. In vitro oxiconazole is highly effective against many dermatophytes, including Trichophyton rubrum, Trichophyton mentagrophytes, Trichophyton tonsurans, and Epidermophyton floccosum. After application to the skin, oxiconazole is rapidly absorbed into the stratum corneum, maximum concentrations often being attained within 100 minutes. Fungicidal concentrations are maintained in the epidermis, upper corium, and deeper corium for at least five hours, and levels exceeding the minimum inhibitory concentrations of susceptible fungi are present in the corneum, epidermis, upper corium, and the hair follicle for over 16 hours. Applied once daily for four weeks in the treatment of tinea pedis or for two weeks in the treatment of tinea corporis, tinea cruris, and tinea versicolor, 1% oxiconazole cream has produced mycologic and clinical cures in at least 80% of patients. In plantar-type tinea pedis caused primarily by T rubrum, once-daily oxiconazole cream resulted in a mycologic cure in 76% of patients. The efficacy of once-daily and twice-daily regimens is similar. In comparative clinical trials of various types of dermatophytoses, oxiconazole was shown to be as effective as or more effective than miconazole, clotrimazole, and tolnaftate creams, and as effective as econazole and bifonazole creams. Tolerability of oxiconazole and the other antifungal creams was similar; in irritation studies oxiconazole was better tolerated than econazole. Oxiconazole cream exerts no detectable systemic effect since only a negligible amount is absorbed from the skin. Once-daily use of oxiconazole cream could be valuable in patients with a history of noncompliance with multiple-daily regimens of other topical antifungal agents.

Beclomethasone dipropionate aqueous nasal spray for seasonal allergic rhinitis in children.

A 3-week double-blind, parallel group study comparing the effectiveness and safety of an aqueous formulation of beclomethasone dipropionate (BDP-AQ) versus placebo was undertaken in 101 patients. Children aged 5 to 13 years with a diagnosis of seasonal allergic rhinitis received one spray in each nostril twice daily of either BDP-AQ (42 micrograms/spray) or an identical placebo spray. Patient assessment at the end of treatment indicated statistically significant improvement in nasal symptoms for BDP-AQ patients. The physicians overall evaluation of treatment indicated that the BDP-AQ-treated patients experienced significantly greater (P = .012) improvement as compared with placebo-treated patients. There was no difference in the incidence of adverse events between the two treatments. The results demonstrate the effectiveness and safety of BDP-AQ nasal spray in the treatment of seasonal allergic rhinitis in children.

Triazolam: a review of its pharmacological properties and therapeutic efficacy in patients with insomnia.

Triazolam is a triazolobenzodiazepine with hypnotic properties, advocated for use in acute or chronic insomnia, situational insomnia in hospitalised patients, and insomnia associated with other disease states. As triazolam has a relatively short half-life of about 2 to 3 hours in healthy subjects and has only 1 short acting active metabolite, alpha-hydroxytriazolam, it would seem more suitable as an hypnotic than longer acting drugs such as flurazepam, nitrazepam or flunitrazepam, particularly when residual sedative effects on the day after ingestion are undesirable. Thus, with usual hypnotic doses of triazolam (0.25 or 0.5 mg) impairment of psychomotor and cognitive function is generally not carried over into the day after ingestion, although at doses of 1 mg or greater, residual effects may appear. In short term comparative studies triazolam was clearly superior to a placebo, and was at lest as effective as flurazepam, or other benzodiazepines such as nitrazepam or diazepam, in hastening sleep onset, reducing nocturnal awakenings, and increasing sleep duration. In other studies it was often superior to chloral hydrate, methyprylone or quinalbarbitone (secobarbital). In a small number of patients with chronic insomnia receiving extended treatment with triazolam in a clinical setting or in some sleep laboratory studies, no evidence of tolerance occurred; however, some evidence of reduced effect with repeated administration has been reported in one sleep laboratory study. Thus, a definitive statement about the likelihood of tolerance occurring on repeated administration is difficult to make at this time.