<s>[INST] What could be causing my husband to have BP drop? His is usually 12/80 but today it dropped to 55/40 when he walked in the house after going out to lunch and he felt extremely dizzy.Thirty minutes later I did the BP again and it is 75/58.What causes low blood pressure?Thanx Marilyn [/INST] HIWell come to HCMI really appreciate your concern hypotension may not be it self but there are certain condition which could cause this and that would be medical emergency that demand immediate medical attention, in my opinion better to get done the clinical examination there his blood pressure would be measured with authentic sphygmomanometer, hope this information helps, take care. </s>