Medications and other drugs
What does the Big Book say about one using medication when prescribed by a doctor? Is it left up to each individual and his/her Higher Power? Is their one blanket answer or does the type of prescription determine the its "acceptable" use?
There certainly is no blanket answer and the subject is not covered in the Big Book. There is a General Service Conference approved pamphlet that may be of some help to you. Called The AA Member - Medications & other Drugs
the pamphlet can be viewed (in PDF format) here
The quick answer is that it is indeed up to each individual to decide what they feel comfortable taking. Sobriety in AA is typically measured in terms of not drinking alcohol but there are thousands of different opinions among individuals about what they think "real" sobriety is. For more on the topic of defining sobriety please see this answer
The reality is that people in AA take all manner of medications and most do so while considering themselves to be sober - even with narcotics when taken for pain. The sentiment that those in recovery must avoid all "mood and mind altering" drugs does not come from AA but originates in rehabs, CA & NA.
AA members do not give medical advice to each other - we leave the medicine decisions to the doctors and hope the patient can find the courage to fully honest with their prescribers.
Perhaps most important is the degree to which a person can be honest with themselves about their motivations for taking a drug - whether it is medical or recreational.