Metformin is effective in reducing testosterone levels and in making the menstrual cycle more regular. Metformin starts to improve the prospects for fertility in a few weeks. Metformin is a wonderful drug to induce ovulation in PCOS patients and that it is justifiable to use it as a first-line treatment.
Temporary nausea and/or diarrhoea, loss of appetite, increased abdominal (belly) gas, a metallic taste is considered as common side effects of Metformin. These symptoms occur with variable degrees in patients and in most cases resolve spontaneously. The severity of side effects can be reduced by gradual administration of Metformin and titrating the dose increase. 850 mg daily seems to be higher dose to start with. So you can talk to your doctor about starting with 500 mg daily and then gradually decreasing the dose, if you experience intolerable side effects. This can lessen the side effects and allow tolerance to develop.
Slow release Metformin can be associated with fewer side effects. Metformin can also lead to vitamin B12 malabsorption in the distal ileum in approximately 1030% of patients which is an effect dependent on age, dose and duration of treatment. However, if you experience, hives or symptoms of lactic acidosis, such as rapid breathing, excessive sweating, cool and clammy skin, sweet-smelling breath, belly pain, nausea or vomiting, and/or confusion call your doctor, right away.
Hope you get on well with Metformin. Good luck!!!