Pharmacokinetics of esomeprazole following varying intravenous administration rates.

There are situations where the use of an oral proton pump inhibitors is not possible. In such situations an intravenous route is the preferred alternative. An intravenous formulation of esomeprazole has recently been developed. This study was designed to evaluate the pharmacokinetics and tolerability of single-dose intravenous esomeprazole using different rates of administration. The study was an open randomised, cross-over design in healthy male and female (n = 24). Esomeprazole 40 mg intravenously was administrated as an infusion over 10, 15, 20 or 30 min., or esomeprazole 20 mg intravenously as an injection over 3 min. There was a wash-out period of at least 6 days between dose regimens. It was demonstrated that increasing the rate of intravenous infusion of esomeprazole 40 mg resulted in higher Cmax values (geometric means; 5.2-7.6 micromol/l), but the AUC values remained relatively constant (7.1-7.2 micromor/l). As expected esomeprazole 20 mg administered as a 3 min. intravenous injection had lower Cmax (3.6 micromol/l) and AUC (2.9 micromol.r/l) values than any of the infusions of esomeprazole 40 mg. Intravenous esomeprazole was well tolerated in this study. In conclusion, any variation in the infusion rate of esomeprazole 40 mg intravenously has little effect on the pharmacokinetics of esomeprazole in healthy volunteers, which provides flexibility in the choice of dosing regimens.

Intravenous Esomeprazole 40mg is Effective for the Control of Intragastric Acid Levels Whether Given as a 3-Minute Injection or a 30-Minute Infusion.

BACKGROUND: An intravenous (IV) formulation of esomeprazole has been developed as an alternative to oral administration. To meet the needs of different clinical situations it would be preferable if an IV dose could be administered as either an injection or an infusion, while producing similar effects. AIM: To compare the effects of IV esomeprazole 40mg given as a 3-minute injection or a 30-minute infusion on intragastric pH during single and repeated once-daily dosing in healthy subjects. METHODS: In this single-centre, double-blind, double-dummy, randomised, two- way crossover study, subjects were randomised to receive either a 3-minute IV injection or a 30-minute IV infusion of esomeprazole 40mg. Both regimens were given once daily for 10 days. After a washout period of at least 13 days, subjects were crossed over to the other treatment. Intragastric pH monitoring was performed on days 1 and 10. Blood samples were also taken throughout days 1 and 10. RESULTS: Data were available from 41 subjects. Time with intragastric pH >4 was 3.1h/24h at baseline, increasing to almost 8h in association with IV esomeprazole injection or infusion on day 1, and to >13h on day 10. Geometric mean time with pH >4/24h ratios (injection/infusion) were 0.99 on day 1 and 1.03 on day 10. Mean esomeprazole AUC values were approximately 15% higher with the injection than the infusion, but 90% CI limits for geometric mean AUC ratios ranged from 1.07 to 1.23, indicating bioequivalence. CONCLUSIONS: IV esomeprazole 40mg provides similarly potent acid control whether administered by injection or infusion.

Pharmacokinetic study of esomeprazole in patients with hepatic impairment.

OBJECTIVE: To evaluate the pharmacokinetics and safety of esomeprazole (Nexium), the S-isomer of omeprazole, after repeated oral dosing in patients with hepatic impairment. DESIGN: Single-centre, open-label one-way study. METHODS: Twelve patients (aged 40-60 years) with mild to severe hepatic impairment received once-daily oral esomeprazole 40 mg for 5 days. Serial blood samples were drawn up to 24 h post-dose on day 5 to determine plasma levels of esomeprazole and its metabolites. Pharmacokinetic parameters were compared with an historical control group of 36 gastro-oesophageal reflux disease (GORD) patients (aged 29-58 years) with normal hepatic function. RESULTS: Esomeprazole was absorbed rapidly (mean maximum plasma concentration (Cmax) 6.1 micromol/l, mean time to Cmax (tmax) 1.9 h) and eliminated rapidly (mean plasma elimination half-life (t1/2) 2.1 h). Elimination of its pharmacologically inactive sulphone and hydroxy metabolites was more gradual. Patients with mild hepatic impairment had area under the plasma concentration-time curve during the dosage interval (AUCtau) and t1/2 values largely within the range of the control group. In patients with moderate hepatic impairment, t1/2 values were similar and AUCtau was slightly higher than in controls, whereas both parameters were increased in patients with severe hepatic impairment. The mean ratios of esomeprazole AUCtau, Cmax and t1/2 values in patients with and without hepatic impairment were 1.8, 1.3 and 1.3, respectively. CONCLUSIONS: The steady-state pharmacokinetics of esomeprazole were not altered substantially by mild or moderate hepatic impairment; however, plasma levels of esomeprazole were elevated in severe cases. Thus, dose adjustment appears unwarranted in mild or moderate hepatic impairment, but may be required in some severely impaired patients. Esomeprazole was tolerated well across the spectrum of hepatic impairment.

The effect of the area under the plasma concentration vs time curve and the maximum plasma concentration of esomeprazole on intragastric pH.

OBJECTIVE: The aim of this study was to create a useful model of the effect of the area under the plasma concentration vs time curve (AUC) and the maximum plasma concentration (C(max)) of esomeprazole on intragastric pH, measured as the percentage of total time with intragastric pH above 4 (%pH>4) during a 24-h period. METHODS: The evaluation is based on esomeprazole data from two crossover studies. In the first study ( n=36), intragastric pH and plasma concentrations were measured on day 5 of repeated once-daily 20-mg and 40-mg doses of esomeprazole during fasting conditions. In the second study ( n=24), measurements were made on days 1 and 5 of repeated once-daily dosing with 40 mg of esomeprazole under fasting and fed conditions. A model was applied in which the logistic function of %pH>4 was assumed to be linearly dependent on log-transformed AUC and C(max). The effects of repeated dosing and of fed relative to fasting conditions were included in the model, and the interindividual variation in %pH>4 was accounted for. RESULTS: The effect of the pharmacokinetic variables AUC and C(max) of esomeprazole on %pH>4 can be adequately described by a model using a logistic function for %pH>4 and a normally distributed error. In this model, log-transformed AUC and C(max) were both statistically significant. The model showed that for a fixed AUC, a decrease in C(max) gives an increase in %pH>4. A decrease in AUC, keeping C(max) fixed, gives a decrease in %pH>4, but a simultaneous decrease in C(max) and AUC will result in a less pronounced decrease in %pH>4. The model may be used for predicting differences in %pH>4 between two formulations, based on assessments of AUC and C(max). Repeated dosing gave an increased %pH>4, where approximately half of the increase stemmed from increased AUC and C(max), and the rest could be attributable to the persistent blockade of the proton pumps. Food intake reduced AUC and C(max) but had no obvious effect on %pH>4, which is explained by a prolonged time period with quantifiable plasma concentrations. CONCLUSION: The effect of the pharmacokinetic variables AUC and C(max) of esomeprazole on %pH>4 can be adequately described by a model using a logistic function for %pH>4 and a normally distributed error.