Generics Versus Brand Name Drugs
First, I apologize for not having written an entry for quite some time. I just haven’t been properly inspired by anything in particular. I was tempted to write about the SCHIP fight- President Bush vs. most of the rest of the country. I assume that anyone reading this website is quite familiar with SCHIP (you know, the program to fund medicaid for children). Anyway, there was really nothing I could add to the debates other than what I have discussed in earlier entries. Well, maybe I could add a bit more? The fight over SCHIP really has nothing to do with fiscal responsibility, which is one of the main arguments against the current bill which President Bush vetoed. The other argument is that the current bill is sort of creeping socialism- down the slippery slope to a single government-sponsored health insurance plan. Both arguments are frankly ridiculous. The costs for the current bill are like pocket change for the government. Also, the government already pays for about 60% of all health care costs. We are already way down the “slippery slope.” It is also important to remember that although the disucssions are centered aroiund the dear little children, more than 50% of total Medicaid costs are for nursing home care of the elderly who cannot get the care under Medicare as it is currently structured (a topic for a future entry?).
In my opinion, the best argument against SCHIP is that as it is admnistered in most of the U.S., participants are really “second-class citizens” and often can’t even get access to adequate health care. I love the idea of making sure all children can get high quality health care without regard to ability to pay, but SCHIP is not the way (I am encouraged a bit by some of the individual State proposals to use the SCHIP money to buy private insurance for children- that at least, moves us away from the wide-spread problem of poor access to medical care for children with Mediciaid).
Generics vs. Brand Name Drugs
Now, to what I had intended to address in this entry- drugs. I heard part of a piece on NPR the other day about problems with the generic form of the brand name drug Wellbutrin (GlaxoSmithKline). The chemical name for the drug is ibupropion hydrochloride. The drug is widely used for the treatment of depression. It has had its share of controversy, most recently because of concerns that the drug is associated with sucicidal ideation in children and adolescents. Anyway, the current issue is about whether the generic form of the drug is less effective than the brand name, which surely costs much more than the generic “equivalent.”
Pharmacokinetics 101
How can 2 tablets with the same amount of active ingredient (in this case, ibupropion hydrochloride) have different bioactivity (i.e., one drug preparation is more effective than the other)? The answer is in the details. It is well known that the inert ingredients in medications (usually called “filler”) can affect a drug’s absorption rate. Thus, the term “generic equivalent” may be a nisnomer in many cases. The only way true equivalence can be established is to perform rigorous studies comparing the brand name drug and the generic preparation. With respect to antidepressant drugs, the studies would need to address the question of whether or not the two preparations were equivalent in effectiveness and with no significant differences in side effects.
The Data
Apparently there had been quite a number of anecdotal reports of less effective control of depression with the generic form of Wellbutrin. I think many of these reports were ignored given the fact that it was people with psychological problems complaining- just the psychologically impaired patient thinking that the generic was not as good as the brand name. Even when it comes to buying dishwashing detergent, brand name loyalty is strong.
As it turns out, maybe the crazy people aren’t so crazy? Apparently, recent studies have shown that the active ingredient in the generic form of Wellbutrin is released from the tablet much more quickly after being swallowed than from the brand name tablet and thus is excreted/degraded much more quickly than with the brand name tablet. Who’d have thunk it? Actually, lots of people- the manufacturers of the generic drug, the FDA, psychologisyts and psychiatrists, and many others should have thought about it.
What does this have to do with endocrinology?
This website is obstensibly about endocrinologic matters, so what’s the relevance of antidepressant drug matters? Good question. We endocrinologist use drugs and the Wellbutrin story is very relevant to many of the medications we prescribe. For example, there has been a longstanding fight between the manufacturer of the brand name thyroid medication Synthroid (Abbott Pharmaceuticals) and the FDA about the bio-equivalence of various generic forms of the drug (the chemical name is levo-thyroxine). The generics are a bit less expensive than the brand name but a variety of studies have shown big differences in the lot-to-lot potency of some generic forms of the drug vs. the brand name. So, it is not too surprising that many endocrinologists strongly favor Synthroid over any of the generic forms of the drug. When I treat patients with generic forms of L-Thyroxine, I tend to order thyroid function tests more often than if the patient is being treated with Synthroid. I bet it ends up costing the patient (or the insurer) more to use the generic than brand name form of the medication?
A second example is a medication for treatment of diabetes insipidus, a condition that is associated with inability to control urine output. The medication is called vasopressin. It is available in tablet form for mild cases (or for treating enuresis) but patients often require a nasal spray which they typically use 1-3 times daily. There is a generic form of the drug which is quite a bit less expensive than the brand name drug (Desmopressin). Unfortunately, the generic requires refrigeration and is associated with much more nasal irritation than the brand name which can be left at room temperature and seems to cause very little nasal irritation. Same active ingredient but …………
I could list quite a few more examples, but you probably get my point. I am not necesssarily trying to defend manufacturers of brand name products which are often far more pricey than they should be. I only want to point out that before the term “generic equivalent” is given to a medication, rigorous studies need to be performed which include not only studies of bioactivity, but also of side effects and inconveniences (e.g., requiring refrigeration or not).