Midazolam onset of action undergoes rapid absorption from gastrointestinal tract. Only about 50% of the orally administered dose of midazolam reaches the systemic circulation, reflecting extensive first-pass metabolism.
It is highly protein bound and this does not depend on the plasma concentration of the drug. The short duration of the drug is due to its lipid solubility, leading to rapid redistribution from to inactive tissue as well as rapid hepatic clearance.
The clearance of midazolam is 6-11 mL/kg/min. The elimination half-life of midazolam is 1-4 hours. The elimination half-life may be doubled in elderly patients reflecting aggregated decrease in hepatic blood flow and possibly enzyme activity.
Elimination half-life of midazolam onset of action is increased in congestive heart failure, hepatic cirrhosis, and chronic renal failure. It is markedly and unpredictably increased in critically ill patients with multi-organ failure.
The mean relative bioavailability of midazolam onset of action following IM administration is greater than 90%. Following lM administration, the mean time to peak midazolam plasma Concentrations is 150.5 hour.
Peak concentrations of midazolam as well as 1- hydroxymethyl midazolam after IM administration are about one-half of those achieved after equivalent IV doses. There is, however, no direct correlation between clinical effects and blood levels of midazolam onset of action .
If you have any more questions on this topic or any other health related topic ask a Doctor here.