The right common carotid artery arises from the brachiocephalic trunk (posterior to the right sternoclavicular joint), whereas the left common carotid is a branch of the arch of the aorta and hence has a thoracic portion before it reaches the neck (posterior to the left sternoclavicular joint).
Metformin Dosing. The recommended starting dosage of metformin is  500 mg twice daily. The maximum dosage for children age 10 to 16 is 2000 mg, and for adults age 17 and older is 2550 mg. Your dose should be increased only when necessary and should be increased slowly in order to avoid side effects.
Doses above 2000 mg may be better tolerated given 3 times a day with meals. The usual starting dose of GLUCOPHAGE XR (metformin hydrochloride) Extended-Release Tablets is 500 mg once daily with the evening meal.Dosage increases should be made in increments of 500 mg weekly, up to a maximum of 2000 mg once daily with the evening meal.oses above 2000 mg may be better tolerated given 3 times a day with meals. The usual starting dose of GLUCOPHAGE XR (metformin hydrochloride) Extended-Release Tablets is 500 mg once daily with the evening meal.