Let us start with the Cancer drug METHOTREXATE. Given to patients with choriocarcinoma and not fibroid as some one very erroneously wrote some where very recently.
The another very important use of Methotrexate is helping both unmarried as well as married women with ectopic pregnancy which otherwise can kill them if undetected and ruptures. The dose recommended is 50 mg/m2 which means for a 5 feet 1 inch female with 65 kgs the dose would be around 82.5 mgs. It is a small dose therapy unlike high dose therapy used for cancers in the dose of 500 mgs/m2.You would expect hair fall, mouth ulcers, patches, bone marrow suppression at high dose but at 50 mg/m2 it is quite safe medicine recommended by RCOG and ACOG. One would be really unlucky to be sensitive to such a minuscule dose of such a wonderful 'cancer' medicine.
Another one is metformin. It was and is used for Type II Diabetics but with equal vigour it is being used in women with PCOD and that doesn't make them diabetic.
Oral contraceptive pills are used for treating various hormonal imbalance apart for contraception.
Vit B complex is a supplement but at times in patient's with recurrent miscarriage and homocysteinuria it becomes the treatment.
SO KNOW THE EXACT REASON WHY YOUR DOCTOR PRESCRIBED YOU A MEDICINE.