How safe is your medicine?-A A +A
To Your Health
Friday, September 6, 2013
THE last two issues of our column generated so much reaction, both interesting and amusing because of the rather unsettled controversial issue as to whether generic medicines are as effective and safe as branded medicines. Corollary to that is another ticklish question as to whether foreign-multinational pharmaceutical companies deliver or produce better, safer medicines than local drug firms. Admittedly, the issue of herbal medicines sourced from herbal sources, as alternative therapeutic agents supposedly better add more fire to an already hot issue.
Again, prudence dictates that before we make firm conclusions and make strong pronouncements, we have to lay down more basic information about drugs. The word “innovator" is a term that applies to the original or the very first medicine of its class introduced into the consumer's market, the patients. The drug is therefore the result of a long, tedious process of experimentation, laboratory procedures of isolating the crucial component to acquire the essential substance that would eventually translate in a much-desired therapeutic effect. As I have said in my last two articles, the wannabe or soon-to-be-drug must undergo very rigid, stringent evaluation before it even reaches phase I of drug assessment. The word “in vitro" means data obtained in a laboratory situation probably using animal models, whereas the word " in vivo " refers to an actual within the body occurrence. And it is useful to establish at this point in time, that many drugs behave differently in these two situations, meaning that what may be true in a lab situation may not be necessarily true inside the body of the patient.
Another item that needs clarification is “bioavailability" which is the fraction of an administered drug that reaches the systemic circulation or the bloodstream of the patient. It is expressed as the fraction of drug that gains access to the blood of the patient in a "chemically unchanged form." For example, if 100 mg of a drug is given and 70% of the drug is absorbed unchanged, then the bioavailability is 70%. Now the issue is, drug A and B may have the same bioavailability, example 70% but drug A showed that much amount of drug in the blood after two hours, whereas drug B, showed the same amount of unchanged drug in the blood after 4 hours. Now, dear readers, you don’t have to be a doctor or a mathematician to know which drug is better.
Before we tackle another issue, allow me to tell our readers that the innovator drug, being the result of much research involving the best minds in the industry, not to mention the initial trial and error ups and downs in the making of the molecule, plus the money spent in its production, the International Patent Office " protects" the owner of this innovator drug by preventing any other drug firm to produce copy-cats- usually much-cheaper- versions of the innovator drug. After a reasonable period of time- probably the originator pharmaceutical firm would have obtained already ROI or return of investments, then is drug is considered “off patent". This would open the flood gates to all wannabe producers of the innovator drug, especially so if it has gained wide popularity and successful patronage from the physicians and patients alike. That explains why, in the Philippines, there may be hundreds of amlodipines, simvastatins, even the more expensive clopidogrel has a lot of "clones", so to speak. The nagging question, “Are they all the same?" In terms of efficacy and more importantly, in terms of safety?
Two drugs are said to be bioequivalent if they show comparable bioavailability and the same time to achieve maximum or peak concentration of the drug. Therefore, drug A and B are bioequivalent if it takes the same four hours for both drugs to be bioavailable, say 80% in the blood. However, still that does not mean they are as effective or as safe. Two similar drugs are "therapeutically equivalent" if they have comparable efficacy and safety. Clinical efficacy depends on both the blood or serum drug concentration and the time after administration required to reach peak concentration, and another crucial item is how soon a drug is finally excreted, thus affecting its sustained bioavailability. Therefore, from a clinical standpoint, two bioequivalent drugs may not be therapeutically equivalent.
Now, to the most important question about generic medicines. First, the author believes that the prestige of the maker of the innovator drug is at stake. Therefore, they makes sure that these vital factors are properly addressed, somehow giving us, the consumer some reassurance that, indeed the drug is safe. Thus in all honesty, I feel better giving my patients the innovator drug, provided the price is democratic. This is not to say however that only-foreign based drug companies [produce superior medicines. My experience , shared by many colleagues of mine, with medicines produced by Unilab has been excellent, with their medicines priced within the reach of Filipinos, providing cure and relief to the maladies of my patients.. At the same time, my patients have also obtained therapeutic benefits from generic medicines, priced much lower than the innovator drug. So, the take home message here is, at least for me, the innovator drug , the result of many years of evaluation has an edge over generics and definitely, it would be my preferred choice especially if the patient has a serious, life threatening condition. Generics, in my practice are used for mild to moderate clinical conditions, and even in critical situations provided that I have basic information about the corporate values and reputation of the drug firm. Yes, dear readers, there are also excellent generic medicines and your favorite doctor can mention some. Incidentally, generic medicines are found in ALL drugstores so again, for more assurance about their safety, why don’t you get your generic medicines from drugstores which have track record of safety and quality of their medicines.
Published in the Sun.Star Baguio newspaper on September 07, 2013.