Question

A woman (weighing 120 lb) was found dead in her bed with an empty bottle of codeine (60 mg tablets) beside her. The label on the bottle said to take two pills a day, one in the morning and one at night. Her gastric contents contained 820 mg/L codeine (450 mL total volume) and her blood contained 2.5 mg/L codeine. (The GC/MS analysis also showed 0.080mg/L morphine, a metabolite of codeine.) If the volume of distribution (Vd) of codeine is 3.5 L/kg, what is the minimum number (ignoring the morphine) of tablets that the victim had ingested? Is this number consistent with an intentional drug overdose (suicide)? (Hint: dose amount = Vd x mass x concentration).

Answer 1

The total number of tablets ingested must be based on the amount of drug found in the gastric fluid as well as in the blood.

The mass of drug found in the gastric fluid was:

• mass = (concentration)(volume) = (820 mg/L) (0.450 L) = 369 mg

The mass of drug found in the blood was:

• mass = (Vd)(mass)(concentration) = (3.5 L/kg)(120 lb)(0.454 kg/lb)(2.5mg/L) = 477 mg

Thus, the total mass of drug ingested was

369 + 477 mg = 846 mg

the number of tablets must have been

• Gastric contents: 369 mg /(60 mg/tablet) = 6 tablet
• Total contents :    846 mg/(60 mg/tablet) = 14 tablets

The large number of tablets in the gastric fluid and the large total number are both consistent with a suicide.