Benzodiazepines

Diazepam
Lorazepam
Tempazepam
Midazolam

Indications

Lorazepam, diazepam: sedation, premedication, EtOH withdrawal, status epilepticus, muscle spasm.
Tempazepam: hypnotic.

Mechanism

Not fully elucidated, but works by enhancing the effects of GABA.

Adverse effects

Sedaton (warn about driving and heavy machinery). Respiratory depression. Dependence (more likely with longer acting benzodiazepines like lorazepam).
Reverse with Flumazenil (1,4-imidazobenzodiazepine derivative). They are not removed by haemodialysis.

Pharmacokinetics

Lorazepam t½=16. Effects last 6–8 h.
Diazepam t½=20 at 20 aet. 80 at 80 aet. Diazepam is relatively insoluble in water and is highly irritant to veins, causing thrombosis. Diazemuls is a soyabean oil emulsion of diazepam which is less phlebotoxic.
Midazolam t½=3 h. Onset 15 min. Amnesia 30 min.