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The Trypan Story | |
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Headache is one of the oldest disorders known to man. The history
of headache treatment is replete with accounts of exotic and dreadful
forms of treatment, including drilling holes in the skull and wrapping
warm goat dung around the afflicted person's head.
Over the years, the range of options progressed to the point of using narcotics and other forms of pain medicines. Americans devoured over-the-counter medications, often to the tune of 20,000 tons of aspirin per year. Other than pain medications, however, the only migraine-specific agent we had was ergotamine. Derived from a fungus on rye, ergotamine is a potent constrictor of blood vessels. For years, it was used in multiple forms, including injectable, suppository, oral, and sublingual forms. Unfortunately, the side effects were many because it is "dirty" in the pharmacological sense of the word, meaning that it affects multiple areas of the body. A problem with the use of analgesics and ergotamine was that occasionally it led to the phenomenon of analgesic-rebound headache or ergotamine-rebound headache, whereby patients began to overuse the drugs and to sustain a rebound effect. In other words, the more drugs one took, the more pain one developed; a vicious cycle was set up and perpetuated. This is a true case of the tail wagging the dog. In the early 1990's, sumatriptan was released. This was a truly remarkable compound. It had been appreciated for a long time that a chemical called serotonin was pivotal in the causation and relief of migraine. It was known that if serotonin was infused into the human body at the time of a migraine, the migraine could be alleviated. However, serotonin was also an extremely "dirty" drug with numerous side effects, some of them potentially dangerous. In Great Britain in the 1970's, the physician and scientist Patrick Humphrey discovered that serotonin's multiple actions throughout the human body were mediated by different "receptors" on various organs, including blood vessels. Think of a receptor as a "docking site" that is specifically designed to receive an incoming vessel. There are different docking sites for different regions of the body, thus allowing the molecule to have different modes of action at the various chemical docking sites. For instance, serotonin may cause the release of a certain chemical in one organ but may inhibit the release of that same chemical in another organ. Different receptors, different actions! Humphrey realized that the receptors on the blood vessels of the head and neck had their own unique receptors, and he set about to create a "vessel" that would bind to the docking sites only in these regions. Thus, the "triptan" molecules evolved. Sumatriptan and serotonin are chemically very similar. After much work and many millions of dollars in research, a true designer molecule was created that would "dock" only on the binding sites in the blood vessels of the head and neck. The first true migraine-specific drug was born. Sumatriptan is the prototype molecule. It has many of the features that the other drugs lack: 1) It is highly specific; 2) it acts almost as an antidote for the physiologic processes involved in migraine; 3) it is safe; and 4) it is effective. The drug has been available in injectable form since 1992, and now is available as a tablet and nasal spray. Millions of prescriptions have been used worldwide with an extremely low side-effect rate. Many patients experience what is now called the "triptan rush" after taking this medication, especially with an injection. This is a mildly unpleasant tightening or burning sensation around the head and neck that usually disappears within a matter of minutes. Most patients choose to ignore this minor side effect - especially since it is usually much less bothersome than the headache itself! One has to be careful with the use of this drug in the elderly population, especially in those who have unstable cardiac disease or untreated hypertension. However, there has been ample experience with the use of the drug in this population, and it has proved to be remarkably safe. Other triptans have continued to roll off the production line. Zolmitroptan was released at the end of 1997, naratriptan and rizatriptan arrived shortly afterwards, and recently almotriptan, frovatriptan and elatetriptan have been released. Many of these triptans share the same drug profile. They are migraine specific, and they reverse the pathologic processes of migraine, especially vascular dilatation. There are some pharmacological differences among the various compounds, primarily regarding onset of action and length of action, but there are enough similarities that they can all be classed together as triptans. Side effects: Because they are pharmacologically "clean," their side-effect profile is excellent. Still, they should not be used in scenarios where there is a high index of suspicion for heart and/or vascular disease. These drugs should also be avoided in pregnancy. Each individual medicine may have their own "minor" side-effects such as drowsiness, mild dizziness etc. but overall they are extremely safe and well tolerated medications. Is there any overall winner in this family of medications? The answer is no; we the physicians and patients are the winners since we now have more choices in the treatment of migraine than ever before. |
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This site is for information only. It is not intended to replace consultation with your physician.