Is it safe to give adeonsine for a REGULAR wide complex tachycardia NOS?

Yes.

A retrospective observational study by Marill et al noted no adverse events when adenosine was administered to REGULAR wide complex tachycardias NOS (not otherwise specified), which after further evaluation were classified as either SVT with aberrant conduction or VT.

In fact, there is only a single case report of destabilization of VT to ventricular fibrillation after treatment with adenosine. If you make it happen again, write it up; you'll be number duce.

An IRREGULAR wide complex tachycardia caused potentially by an accessory pathway (ie WPW) with atrial fib is a whole different ball game. Step away from the adenosine.


Source

Marill, K et al. "Adenosine for wide-complex tachycardia: Efficacy and safety" Crit Care Med 2009 Vol. 37, No. 9.