This really depends on many factors. How many mg is in each pill, the person's weight, medical condition, etc. Either way, it does seem that 10 pills a days is way too much no matter if the dosage is even low. People should always take the prescribed amount and I have never heard of any doctor prescribing 10 pills a day. It sounds like you are worried and you should try talking to friend to see if there is a way you can help.
Overdoses from benzodiazepines alone (like Valium) are actually really rare, although they can happen. In terms of toxicity benzodiazepines are pretty safe, but they can be very highly addictive. The danger of taking a large amount of Valium probably comes more from potential interactions with other drugs. Taking Valium in combination with other sedating substances is really dangerous. An overdose of Valium in combination with alcohol, opioids, barbiturates, tricyclic antidepressants, antipsychotics, or even antihistamines may be fatal.
I don't know how much is too much, only that 10 pills a day is above the normal prescribed dosages.
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