hospital straight away.
Painkillers r normally fatal if u have too many only it takes several days & hurts like hell.
Send in friends or anyone else she will speak to to find out why.
Take the 'why' very fking seriously & act on it.
common reasons r bullying, abuse, rape, possible pregnancy & scared of ur reaction, isolation, realtioship gone bad,. unable to get a boyfriend, fell in love nly boyfriend played & dumped her publically.
Most of these u can pre empt with self defence, social skills, helping her pull (parents hate that, but better a sexaully active happy daughter on contrception then a dead daughter), & be alert to any questions out of the blue that could indicate serious trouble.
councelling may help but u need to target the root problem.
It may mean taking quite a bit off time off work.