Benzodiazepine half life is commonly administered through oral, intramuscular and intravenous routes.
Intramuscular absorption of diazepam is erratic, whereas midazolam and benzodiazepine half life have good bioavailability through this route.
Diazepam and lorazepam are well absorbed from gastrointestinal tract. However, meals and antacids may decrease absorption from the gastrointestinal tract.
Midazolam has also been used through intranasal, buccal and sublingual routes.
Benzodiazepines are highly lipid soluble and rapidly penetrate the blood-brain barrier.
Quick redistribution of benzodiazepines to the other tissues produces rapid emergence from sedation, particularly for midazolam. The moderate lipid solubility of lorazepam is responsible for its delayed onset of action.
Benzodiazepine half life is metabolized primarily by oxidation and glucuronide conjugation.
The metabolites of diazepam, lorazepam and desmethyl diazepam are active; and slow hepatic extraction and large volume of distribution are responsible for prolonged duration of action of diazepam. The long duration of action is due to increased affinity towards the receptors.
The metabolites are chiefly excreted through urine and therefore renal failure prolongs the effect. Benzodiazepines do not produce enzyme induction, as far as benzodiazepine half life is concerned.
You can read more about General Anesthesia here.
If you have any questions related to your health do visit Ask a Doctor website.