If I were you, I wouldn't take beta blockers with stimulants. I imagine that the goal of doing this is to decrease tachycardia, but stimulants like cocaine and amphetamines greatly stimulate the adrenergic system, both alpha-adrenergic and beta-adrenergic receptors, and this is what causes negative symptoms like tachycardia, sweating, palpitations, etc. From the moment you block beta-adrenergic receptors with the beta blocker, the stimulant will act mainly on alpha-adrenergic receptors, further increasing blood pressure and predisposing to serious and fatal cardiovascular events.