How much lorazepam is lethal?

Answer 1

A surprisingly huge amount may -- or may not -- be lethal. The LD50 (lethal dose for 50% of the test exemplars) for Lorazepam is 4500mg/kg for rats, which should be pretty close to human. Therefore, a 110lb person would require about 2,250x2mg tablets just to get to the 50% lethality index. This is far more than one would likely be able to keep down.

Benzodiazepams, the family Lorazepam belongs to, is particularly not prone towards lethality.

This does NOT mean it's okay to exceed your doctor's dosage advice on this prescription only medication, as the potential for damage still exists.

Answer 2

Lorazepam has been found to have been lethal at concentration of 0.5 mg/L of blood and toxic at 0.3 mg/L of blood.1, 2 Determining cause of death is more complicated than simply looking at these levels, and the autopsy, medical history, and presence of other substances must be taken into account. But the literature has documented these levels as lethal. For more information about lorazepam overdose or other overdoses from benzodiazepines, see www.overdoselaw.com

1Schultz M, Schmoldt A. Therapeutic and Toxic Blood Concentrations of More than 800 Drugs and other xenobiotics. Pharmazie 2003;58:447-474.

2Baselt RC. Disposition of Toxic Drugs and Chemicals in Man, 8th ed. Biomedical Publications, Foster City, CA, 2002.

Answer 3

3300 mg (assuming no other respiratory depressants, such as alcohol, have been ingested)