What is the best time frame to utilize intra arterial verapamil for vasospasm after subarachnoid hemorrhage?

We do not use AA verapamil prophylactically. We follow our patients in the Neuro ICU with daily transcranial Doppler. If they have clinical signs or symptoms of vasospasm and TCD and CTA evidence of spasm, we take them immediately and usually perform IA injections daily until radiographically and cl...