Brief Answer:
individual levels low,but overdose may be possible

Detailed Answer:

Thank you for your query.

The average toxic (may be fatal) blood level of amphetamine is 2500 ng/ml; methamphetamine is around 1400ng/ml; the dose range is highly variable for free morphine with 0- 128ng/ml levels in survivors compared to 0- 2800 ng/ml level in non survivors. Similarly the mean concentration of codeine in fatal cases is around 1200 ng/ml; butalbital is around 25mcg/ml (with toxic dose range between 10- 25 mcg/ml).

As, you can see, the levels found in blood were much less than than usual toxic doses. However, you need to keep the following in mind:
1. Toxic / lethal dose or overdose of substance abusers is highly variable.
2. It depends upon the age, body weight, built, duration and frequency of use, purity of the substance, etc.
3. Low doses can be toxic or lethal for first time/new users, or those using after a long gap of time (as in this case)
4. Multiple drugs interact and complement the effect of each other, thus increasing the overall toxicity and decreasing dose required for each drug for the same.

However, it certainly appears that the person was not clean and had taken these substances recently (within past 2- 7 days).
I would suggest you share your concerns with your treating doctor, and discuss with him about the same and way to manage the current crisis urgently.

Hope I have been able to satisfy your query. Feel free to contact me for any further clarifications.

Best of luck.
Dr. Sourav.

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