Prescription is prescription because someone has proven dangers.  PROVE
otherwise.  Prescription is controlled.  Why controlled?  DUUUHHH
OTC is no guarantee of safety.  BTW, Tylenol in excess of 400 unnits per day
will cause liver failure in the average person.
AND Tylenol is safer than aspirin.
Nattokinase (non prescription) is safer and more effective than aspirin (non
prescription) or Plavix (prescription) (For blood thinning.)
Aspirin was popular before prescription was even a term.

It doesn't make one bit of difference what YOU take to change the definition
of a word.
Please tell us why YOU (no Doctor) think that certain products may be sold
ONLY under prescription.

BTW  Why is metformin given under controlled conditions ( prescription)

In many people a MAJOR renal problem.
Glyburide
In a single-dose interaction study in type 2 diabetes patients,
coadministration of metformin and glyburide did not result in any changes in
either metformin pharmacokinetics or pharmacodynamics. Decreases in
glyburide AUC and Cmax were observed, but were highly variable. The
single-dose nature of this study and the lack of correlation between
glyburide blood levels and pharmacodynamic effects, makes the clinical
significance of this interaction uncertain (see DOSAGE AND ADMINISTRATION:
Concomitant GLUCOPHAGE or GLUCOPHAGE XR and Oral Sulfonylurea Therapy in
Adult Patients).

Furosemide
A single-dose, metformin-furosemide drug interaction study in healthy
subjects demonstrated that pharmacokinetic parameters of both compounds were
affected by coadministration.

Furosemide increased the metformin plasma and blood Cmax by 22% and blood
AUC by 15%, without any significant change in metformin renal clearance.
When administered with metformin, the Cmax and AUC of furosemide were 31%
and 12% smaller, respectively, than when administered alone, and the
terminal half-life was decreased by 32%, without any significant change in
furosemide renal clearance. No information is available about the
interaction of metformin and furosemide when coadministered chronically.

Nifedipine
A single-dose, metformin-nifedipine drug interaction study in normal healthy
volunteers demonstrated that coadministration of nifedipine increased plasma
metformin Cmax and AUC by 20% and 9%, respectively, and increased the amount
excreted in the urine. Tmax and half-life were unaffected. Nifedipine
appears to enhance the absorption of metformin. Metformin had minimal
effects on nifedipine.

Cationic drugs
Cationic drugs (e.g., amiloride, digoxin, morphine, procainamide, quinidine,
quinine, ranitidine, triamterene, trimethoprim, or vancomycin) that are
eliminated by renal tubular secretion theoretically have the potential for
interaction with metformin by competing for common renal tubular transport
systems. Such interaction between metformin and oral cimetidine has been
observed in normal healthy volunteers in both single- and multiple-dose,
metformin-cimetidine drug interaction studies, with a 60% increase in peak
metformin plasma and whole blood concentrations and a 40% increase in plasma
and whole blood metformin AUC. There was no change in elimination half-life
in the single-dose study. Metformin had no effect on cimetidine
pharmacokinetics. Although such interactions remain theoretical (except for
cimetidine), careful patient monitoring and dose adjustment of GLUCOPHAGE or
GLUCOPHAGE XR and/or the interfering drug is recommended in patients who are
taking cationic medications that are excreted via the proximal renal tubular
secretory system.

Other
Certain drugs tend to produce hyperglycemia and may lead to loss of glycemic
control. These drugs include the thiazides and other diuretics,
corticosteroids, phenothiazines, thyroid products, estrogens, oral
contraceptives, phenytoin, nicotinic acid, sympathomimetics, calcium channel
blocking drugs, and isoniazid. When such drugs are administered to a patient
receiving GLUCOPHAGE or GLUCOPHAGE XR, the patient should be closely
observed for loss of blood glucose control. When such drugs are withdrawn
from a patient receiving GLUCOPHAGE or GLUCOPHAGE XR, the patient should be
observed closely for hypoglycemia.

In healthy volunteers, the pharmacokinetics of metformin and propranolol,
and metformin and ibuprofen were not affected when coadministered in
single-dose interaction studies.

Metformin is negligibly bound to plasma proteins and is, therefore, less
likely to interact with highly protein-bound drugs such as salicylates,
sulfonamides, chloramphenicol, and probenecid, as compared to the
sulfonylureas, which are extensively bound to serum proteins.

Vernon is not the subject.