Aspen Vita Jec B Complex Fortified 100 ml A simple Vitamin B12 injection can trigger a life threatening drop in potassium, Why Does This Happen?, Patients with severe Vitamin B12 Deficiency often have ineffective red blood cell production. B12 Shots Phoenix Arcadia, Scottsdale, Tempe & Glendale Boots Pharmacy are excited to offer a new a Private Vitamin B12 Service which provides a dose of vitamin B12 to eligible customers, aged 18 and over. This includes customers who have: