MRCP2-4773

A 42-year-old man presents with severe pain and aching in his hands and feet upon exposure to cold temperatures. He describes a triad of initial whitening of the fingers due to vasospasm, followed by blue discoloration and then reddening and pain.
The patient is currently on atenolol 50 mg po daily for hypertension and takes sumatriptan for occasional migraines. He has a history of chronic kidney disease with a creatinine level of 200 μg/l. The sumatriptan is discontinued.
What other intervention would be the most appropriate for this individual?