Defining safety tolerance limits
Zoe Diana Draelos · Journal of Cosmetic Dermatology · 2007
Substances used in cosmetic dermatology must be inherently safe – safer than in other medical disciplines – because we treat conditions not traditionally defined as disease. Medications used to treat breast cancer, hypertension, renal failure, and depression all have unwanted side effects. The side effects are inherent due to the chemical alterations the drug produces in the body. Recently, there has been a redefinition of what safety means for already approved medications. The best example was the withdrawal of Vioxx (rofecoxib) from the marketplace. This drug provided pain relief for millions of persons unable to get out of bed or walk without discomfort. It represented a major step forward in terms of inflammation control, but the cardiovascular side effects were felt to be too great for continued sale of the drug. How safe is safe? What are the tolerance limits on acceptable side effects? I have long felt that patients need to accept certain side effects in order to get the benefit of some drugs. Taking medications is an educated trade-off between the good and the bad. The question at hand is whether we are willing tolerate the bad to experience the good. Or, is the good so valuable that the bad is insignificant? This is a personal decision that certainly would vary from situation to situation. Drugs are regulated and prescribed by physicians with knowledge of pharmacology and human physiology. If drugs were inherently safe, they could be purchased over the counter without prescription. This is definitely not the case. The most recent dermatologic drug to come under question in the Orient, the European Union, and the United States is hydroquinone. Hydroquinone is probably the most effective chemical for lightening skin color. It is cytotoxic to melanocytes, a potent oxidant, and causes cancer when ingested by animals. Hydroquinone is rapidly oxidized to the toxic metabolites p-benzoquinone and hydroxybenzoquinone. It is not safe. It is a drug. Should hydroquinone be removed from the over-the-counter and prescription market? Is it worth accepting the side effects to achieve skin lightening? No one ever died from complications associated with skin darkening; thus, perhaps any product used for the treatment of dyspigmentation should be held to a higher safety standard. It should be completely safe and without any side effects whatsoever. If this were the case, the product would be a cosmetic and not a drug. Cosmetics are held to a higher safety standard by the skin care industry, and products causing any type of ill effect are rapidly removed. Of course, the claims associated with such a product would need to be of the cosmetic nature, such as “improves the appearance of irregularly pigmented skin,” and not “lightens skin pigmentation.” If we truly believe that substances used to lighten skin must be without side effect, no drugs for pigmentation problems should be in the prescription realm. As a matter of fact, because most of the products used in cosmetic dermatology are for appearance-related issues, there should be no cosmetic dermatology drugs. This, of course, is ludicrous. Products in the marketplace are driven by consumer demand, and there is a huge demand for cosmetic dermatology products. The popular media is full of articles devoted to cosmetic dermatology procedures and products. Our youth-oriented culture is searching for new and better cosmetic dermatology technology. This then leads us back to our original question. How safe is safe? I am not sure. This is truly a complex question. We need pharmaceuticals that improve the quality of life without causing serious detriment. However, I am keenly aware that there is a good and bad side to everything. For example, taking your children to the movies is good for family entertainment time, but bad because they could be doing their homework. Or, taking a vacation is good for your mental health, but bad because you could be saving the money spent for your retirement fund. I am reminded of that old adage attributed to the Greek philosopher Socrates, “Everything in moderation.” Perhaps this is how we should look at the issue of drug safety. Are we willing to accept a few side effects for an obvious benefit?