Compatibility of midazolam hydrochloride and lorazepam with selected drugs during simulated Y-site administration

Potential of iontophoresis as a drug delivery method for midazolam in pediatrics

Drug delivery to the neonatal and premature pediatric populations is very challenging. This research assessed the potential of delivering midazolam by transdermal iontophoresis as an alternative strategy in pediatric therapy. In vitro experiments used intact and tape-stripped porcine skin as models for the skin barrier function of full-term and premature newborns, respectively. Midazolam transdermal transport was significantly enhanced by applying higher currents, increasing the formulation pH, and optimizing the drug's mole fraction in the vehicle. When the skin barrier was decreased to half of its baseline competence, the passive permeation of midazolam increased by approximately 60-fold; and complete stratum corneum removal led to an additional 20-fold enhancement in permeation. Iontophoresis retained control of the drug transport trough partially compromised skin. However, a very high passive contribution undermined the iontophoretic control when the barrier was fully compromised. Overall, midazolam delivery could be rate-controlled by iontophoresis in most circumstances, and therapeutically useful fluxes could be achieved.

Compatibility of medications during multi-infusion therapy: A controlled in vitro study on a multilumen infusion device

OBJECTIVE

Drug incompatibilities can jeopardize the safety and effectiveness of intravenous drug therapies, especially in the field of anaesthesia and intensive care. Patients receive many drugs simultaneously through limited venous accesses. This study was designed to confirm the impact of a multilumen infusion device on the occurrence of known physical drug incompatibilities.

STUDY DESIGN

In vitro laboratory work.

METHODS

Two infusion devices were studied: a standard single-lumen set and a multilumen infusion access device (Edelvaiss Multiline-8, Doran International). Up to six drugs were infused simultaneously: three acidic solutions of midazolam, amiodarone and dobutamine, and three alkaline solutions of furosemide, pantoprazole and amoxicillin/clavulanate. Saline, Ringer' solution and 5% dextrose were used as hydration vehicles with an infusion rate initially set at 100 mL/h and with stepwise decreases of 10 mL/h until precipitation. Two methods were used to highlight physical drug compatibility according to the European Pharmacopoeia: visual inspection of the extension set and an obscured-light sub-visible particle count test of infusions. The lowest infusion rate value for vehicle infusion to satisfy the two tests in all trials is reported for each infusion device.

RESULTS

The standard set did not satisfy the test in 82% of the assessed drug combinations. The Edelvaiss Multiline-8 was able to prevent the occurrence of drug incompatibilities in 49% of the drug combinations tested. This device is therefore advantageous, especially when simultaneously infusing two or four incompatible drugs.

CONCLUSIONS

Infusion device characteristics have an impact on physical drug incompatibilities. Our results confirm that the Edelvaiss Multiline-8 device prevents physical drug incompatibilities under specified conditions.

Standardization of infusion solutions to reduce the risk of incompatibility

PURPOSE

Although critically ill patients usually have various central intravenous (i.v.) lines, numerous drugs have to be infused simultaneously through the same lines. This can result in potentially harmful in-line incompatibility that can cause decreased drug effectiveness or increased microparticle load. To minimize the risk of these medication errors at an anesthesia intensive care unit (ICU), the preparation and administration of continuously infused drugs were standardized and the practicability in daily clinical routine was evaluated.

SUMMARY

The concentration and diluent of continuously administered i.v. drugs were standardized. The drugs were grouped according to pH, medical indication, and chemical structure. The ICU staff decided to use multilumen central venous catheters, and each group of drugs was assigned to one lumen. Only drugs that belonged to the same group were infused simultaneously through the same lumen; therefore, intragroup incompatibilities had to be excluded before establishing the new drug administration plan at the ICU. The visual compatibility of 115 clinically reasonable intragroup drug mixtures was investigated. All drug combinations were compatible for six hours except mixtures containing thiopental, which was reassigned to a single-line use. In the following year, the practicability of this drug administration plan was evaluated. No deviations were found in the compliance of the staff prescribing and preparing only standardized concentrations and diluents. Further research to investigate the chemical compatibility of the drugs in these multiple mixtures will follow.

CONCLUSION

A project intended to avoid incompatibility among i.v. drugs infused in the intensive care setting included steps to standardize solutions and determine which could be given together.

Continuous infusion of lorazepam versus medazolam in patients in the intensive care unit: sedation with lorazepam is easier to manage and is more cost-effective

OBJECTIVE

To evaluate the effectiveness of lorazepam and midazolam for long-term sedation of critically ill, mechanically ventilated patients.

DESIGN

Double-blind, randomized, controlled study.

SETTING

Medical intensive care unit in a university teaching hospital.

PATIENTS

Sixty-four evaluable adult patients admitted to the intensive care department requiring mechanical ventilation for >3 days.

INTERVENTIONS

Patients were randomized to receive blinded solutions of either lorazepam or midazolam by continuous infusion. The lowest dose that achieved an adequate sedation was infused. The maximum dose allowed for each drug was 60 mg/hr for midazolam and 4 mg/hr for lorazepam. Sedation was assessed initially and at least every 8 hrs thereafter on a seven-point scale if the sedation was adequate and every 2 hrs if it was not.

MEASUREMENTS AND MAIN RESULTS

Measurements included the score on the sedation scale, the time between determination of the desired level of sedation and the achievement of that level, and plasma concentrations. It is significantly easier to reach a desired level of sedation with lorazepam than with midazolam. No difference in recovery was found in the 24 hrs after discontinuation of therapy. The fact that there are many factors influencing midazolam pharmacokinetics may explain the more difficult management of desired sedation levels. The equipotent dose of 10 mg of midazolam proved to be 0.7 mg of lorazepam in long-term sedation. The average cost for therapy with midazolam was approximately ten times more than that with lorazepam.

CONCLUSIONS

Lorazepam is a useful alternative to midazolam for the long-term sedation of patients in the medical intensive care unit and provides easier management of the sedation level. Sedation with lorazepam offers a significant cost-savings.