I am female, 60 yesrs of age and have been taking 2.5mg of Letrazole after being diagnosed with stage 2 breast cancer last July, followed by a mastectomy of the left breast. Apart from some joint pain, in my hip and legs and some pain in my left breast, l have had no other discerning side effects until 2 nights ago. 

After taking my tablet at 10pm, l started to develop a headache within 20 mins at the back of my head. Within 30-40 mins. I felt, extremely cold and developed chills; uncontrollable shaking; stiffness of my neck and joints along with severe bone and muscle pain in my hip, across my back, leg, particularly in my calves and ankle in my right leg. With additional pain in my upper left breast at the site of the tumour, and nausea The pain was horrendous and lasted until around 2am. I took an aspirin and eventually the majority of the pain passed/subsided. I did not take a Letrazole last night as it was a Sunday over the Bank Holiday weekend. I have also not taken a tablet today, as lm deeply concerned that l may have a repeat occurance. I should say, that l had a general anaesthetic nearly three weeks ago, for an unrelated condition and was in hospital overnight. 

Your advice would be most welcome.

Thank you