I am away from home (mt) and am going to run out of my atenolol 25mg about 6 days before i can get my refill. is it safe for me to use my mother's lisinopril 10-12.5 for those 6 days.

Sure, but: It is safe, but probably not necessary. The dose of atenolol is not high enough to cause withdrawal, and it's not dangerous to have higher blood pressure for just 6 days.

Probably not!: If atenolol was prescribed to include to cover palpitations or tachyarrhythmia in addition to treat hypertension then Lisinopril may not help those conditions. Call u r md and let him help u.( Lisinopril will only help hypertension).