Monday, July 15, 2013
The work of track and field took another shot across the bow this week, when three more sprinters were notified that they had failed drug tests. American Tyson Gay and Jamaicans Asafa Powell and Sherone Simpson all tested positive for oxilofrine, a stimulant in the same drug class as amphetamine, and now await their competitive fate to be determined by their sports federations. Gay and Powell were two of the three fastest men in the world this year.
Oxilofrine, also known as methylsynephryn, is available by prescription in some countries to help patients suffering from low blood pressure, but it is not licensed or approved in the US. Instead, it has found its niche in the world of body building because its amphetamine and adrenaline type properties might help with weight loss and fat burning. The problem is not the benefit that it might have but the side effects that can be potentially lethal.
Oxilofrine and similar chemicals can be thought of as uppers, providing an adrenalin boost to the body. Unfortunately, the downsides and complications on the cardiovascular systems can far outweigh the benefits. Patients can develop rapid heart rates, high blood pressure and hemorrhagic stroke or bleeding in the brain.
Most people have episodes of palpitations where their heart skips a beat, beats quickly, beats irregularly or all three. Most often, the episodes are momentary, lasting a second or two and quickly forgotten, but they sometimes persist causing the patient to present to their doctor’s office or the ER. The complaint can be a fullness or heaviness in the chest, an occasional thump or fluttering and shortness of breath. It all has to do with the heart functioning as an electrical pump and an electrical short circuit. The underlying cause is usually benign, but the patient always fears that their heart will stop.
The heart is a two stage electrical pump. An electrical impulse is automatically generated in the atrium or upper chamber of the heart. This impulse causes the atrium to contract and send blood collected from the body, to the ventricle or lower chamber of the heart. The electrical impulse is slowed for a fraction of a second at the atrioventricular junction allowing the ventricle to completely fill and then the electricity allows the ventricle to contract, pumping blood to the body. The heart goes lub-dub, the cycle repeats itself 60-80 times a minute and all is good.
Palpitations are caused when the electrical system becomes irritated. It can be a wiring problem that needs fixing or it can be due to the effects of “poisons” on the heart, those from within the body or those put in the body. The poisons within include thyroid problems or changes in electrolytes like potassium, magnesium and calcium that can affect the heart’s electrical conducting system. The ingested poisons are those that get converted to adrenalin-like substances and affect the heart. Common ones include caffeine, alcohol, amphetamine, cocaine and over the counter cold medications that contain pseudoephedrine or phenylephrine. Oxilofrine fits in here, as a “dietary supplement”, along with a variety of herbal medicines that can cause the heart to be irritable and drive up blood pressure.
Too often, when a patient presents with palpitations, the episode has passed and the heart rate is normal. It’s like having a noise in your car that magically disappears when you pull it into the mechanic’s bay. Their solution is to come back when the noise happens again or to leave the car and they’ll drive it when they have a chance. Both are not reasonable options for the human body. There are occasional times when the palpitation may be life threatening.
Rapid heart rhythms that originate in the atrium tend not to be emergently life threatening but those that start in the ventricle can be associated with sudden death and it is the doctor’s job to gather enough information to make certain that it is safe for the patient to go home. It’s easy if the monitor shows an occasional premature ventricular contraction (PVC) or premature atrial contraction (PAC) which are normal variants but can cause a characteristic thump in the chest and the sensation of a missed beat. It’s harder when the monitor shows a normal sinus rhythm and electrical conduction.
The history and physical exam, along with a heart monitor strip and EKG, are usually the bare minimum required to figure things out, come to a diagnosis and reassure the patient. Sometimes, the answer is not so clear and more testing is needed. From blood tests to echocardiograms to heart monitors worn at home, the art and skill of medicine is deciding how much or how little technology is needed.
As with much of medicine, the best treatment is prevention. In the case of over the counter medications or dietary supplements, there are chemicals that can cause harm and the key is to avoid them. Your doctor or pharmacist may or may not be aware of the contents of the latest GNC product and it is unlikely that the sales clerk will appreciate the interactions of some of the ingredients with prescription medications. There is a false perception that a drug available over the counter without prescription must be safe. In reality, there is little quality control or public information necessary to release a dietary supplement to market.
There are too many athletes who have failed drug tests because they took a dietary supplement or workout aid that contained a substance not listed on the bottle. That is the position taken by Gay, Powell and Simpson who have declared their innocence. While it may be the truth, the anti-doping agencies do not consider intent. Intent also doesn’t make much of a difference for the non-athlete who suffers a major complication. Whether it is palpitations, heart attack or stroke, the body doesn’t much care what you meant to do.This entry was tagged asafa powell, dietary supplement, oxilofrine, palpitations, tyson gay