I was asked this question by a Endocrinology Obesity specialist recently.
When I responded, Yes,
He asked if I had data for that.
I said we do quite a bit of therapy that is not evidence based. The art of medicine requires we treat patients as individuals.
We presently do not have head to head trials of the four major diet medications.
Does that paralyze us from making judgements as to which diet medication to use first.
The ACA/AHA guidelines on therapy for treating lipids mostly used evidence based medicine and was soundly criticized for that limitation.
The NLA subsequently made additional recommendations to those guidelines and there has been a subsequent consensus statement.
Here I am in a new discipline: The American Board of Obesity Medicine.
The old school of Diet and Exercise is still pushed despite it's dismal 10 year failure in LOOK AHEAD TRIAL.
Yet Diet and Exercise is still in the guidelines in a premiere position.
I am on 5 diet medications
That has to be off label?
Actually, my Endocrinologist and my Obesity Clinic would disagree.
Metformin for DM might be considered a diet medication especially for metabolic syndrome.
Invokana is for DM but I lost 30 lbs. on it when I stopped Insulin.
Victoza for DM is a Diet medication with a different name Saxenda.
Qsymia has phentermine and topiramate started by my Obesity Clinic while I was already on Meformin, Invokana and Victoza.
Is there data for a patient like me. I don't think so.
It is advised not to take topiramate with metformin for fear of metabolic acidosis. This was never advised in the conferences preparing for the Obesity Boards. Invokana has also been linked to ketoacidosis. Again I think these are rare occurrences but should be screened for.
There are just too many permutations of patients to have data for every situation.
We need to approach each patient individually, then follow them closely.
If a patient loses 3% weight on Qsymia after 3 months, I will probably start that patient on Saxenda or Victoza rather than lose that 3% effect.
I suspect adding Victoza will have a great additive effect similar to the ileal brake of Bariatric surgery when bile acids are dumped directly into the ileum by the bypass surgery. The bile acid stimulate secretion of GLP-1 and PYY to cause the ileal brake?
That's the theory. There is a waterfall response even with Gastric bypass surgery. Yet this very expensive surgery while thinking it was all due to restriction of food intake?
Thus as an Obesity specialist I believe it is reasonable to use the medication toolbox to the best of my ability to the best interest of the patient rather than refer the patient immediately to Bariatric surgery.
How to choose which diet medication
This is Harold Bays MD slide from Obesity Medicine Certification Review course in Washington DC in Oct 2015.
Presently PCSK9 has no outcome data yet is being touted strongly as therapy in several areas.
Zetia had no outcome data till recently yet after 8 years the LDLc lowering effect proved effective.
Niacin had it's two trials stopped early after 3 years after falsely significant side effects.
Thus while many guidelines jumped the gun by eliminating Niacin, an inexpensive safe proven drug at 1,000 mg with low dose statin it is still available to the physician to use multiple drugs at low doses for best effect.
A good general principle in the practice of treating chronic diseases such as DM, HTN, HIV and others.