Cynthia R. Biron, RDH
The most talked about prescription drug available today is Viagra (generic name is sildenafil citrate). Viagra is the first oral pill available to treat impotence. It was approved by the Food and Drug Administration (FDA) on March 27, 1998. Since that time over three million prescriptions have been dispensed.
Viagra does not directly cause penile erection, the patient must be sexually stimulated. When blood flows into the corpus caverosum of the penis, the active ingredient in Viagra inhibits the enzyme,
phosphodiesterase type 5 (PDE5). This enzyme naturally degrades cyclic guanosine monophosphate (cGMP), the chemical that causes smooth muscle relaxation and blood flow into the penis for erection. So by inhibiting PDE5, cGMP is allowed to remain available for continued smooth muscle relaxation, blood flow, and erection. The recommended dose is 50mg. taken one hour before sexual activity. Maximal plasma concentrations occur between 30-120 minutes after ingestion. Dosage requirements may differ from patient to patient, whereby patients may only require 25mg., or as much as 100mg. in a single dose. In four clinical trials, patients reported improvement in achieving and maintaining erections as follows:
24% improvement Placebo (n=453)
63% improvement Viagra (n=214)
74% improvement 50mg Viagra (n=391)
82% improvement 100mg. Viagra (n=380)
The drug is not supposed to be taken more than once a day. The most common adverse effects are headache, flushing, and dyspepsia. Three percent of patients taking the drug reported changes in vision, mostly color perception.
Viagra should not be prescribed to patients taking organic nitrates of any kind or form, and organic nitrates must not be administered to patients who are taking Viagra, even in the event of chest pain of a first occurrence. The concomitant use of Viagra and organic nitrates
has caused sudden drops in systemic blood pressure which could result in myocardial infarction and cardiac arrest (see chart of common organic nitrates).
Other cardiovascular drugs have not been known to have adverse reactions with Viagra. There are some incidences where the macrolides, Clarithromycin, Azithromycin, and Erythromycin have effected blood plasma levels of Viagra. In the Viagra user it is recommended that a consult with the patient`s physician be conducted to select the best antibiotic for prophylactic antibiotic or the treatment of dental infections.
The FDA posted a summary of reports of death in Viagra users in response to Freedom of Information requests. The report was prefaced by a list of the limitations of postmarketing spontaneous adverse drug event data. The data cannot be used to calculate true incidence rates, as reports from health professionals are reported voluntarily, under-reported, incompletely reported (missing or incomplete medical histories, diagnosis, drug dosages, concomitant use of drugs and other variables, such as causes of death not proven related to the intake of Viagra, but due to underlying disease or other factors).
The following is a summary from the FDA report on Safety of Viagra, July 22, 1998: From March 27, 1998, until June 1998, 2.7 million prescriptions of Viagra were dispensed and 77 patients died after having been prescribed Viagra - six foreign patients, 24 from unidentifiable reporters, eight deaths suspicious to be Viagra related, but not confirmed, and 39 U.S. patients had definite Viagra-related deaths. Of these, 13 were of unknown or unmentioned causes, two were strokes, 24 were cardiac emergencies (10 myocardial infarctions, nine cardiac arrests, three cardiac symptoms, two coronary artery disease).
The 39 U.S. patients were males. Thirty-one were specified by age - the average was 66 years, median 64, and the range was 48-87. Only 18 were dose-reported at the 50mg. dosage with one exception. Six of the patients were administered an organic nitrate, 14 died or developed symptoms that lead to death during or within two hours of sexual activity, and three died more than two hours after sexual activity. Thirty-three of the 39 patients had risk factors for coronary artery disease.
The FDA did not consider the reports evidence of concern in the safety of Viagra.
Coronary artery disease and impotence
The same predisposing factors that inhibit blood flow in the coronary arteries, can inhibit blood flow in the penis. That is, patients with long-term hypertension, hypercholesterolemia, cigarette smoking, diabetes, obesity, and various cardiac diseases, often also have male erectile dysfuntion. So it would not be uncommon for patients with cardiac conditions or underlying cardiac conditions to seek treatment for impotence through the use of Viagra.
Unless there is more scrutiny in prescribing Viagra, death tolls related to Viagra will continue to rise. Patients who are determined to correct impotency problems will find a way to obtain Viagra.
Sexual activity demands an increase in cardiovascular and myocardial demand, vasodilating effects of Viagra also could increase such demands. The combined effects could cause an anginal episode, myocardial infarction, or even death. Vasodilation lowers the blood pressure by reducing the total peripheral resistance of the circulatory system. The system becomes so large, requires such a large volume of blood to create peripheral resistance necessary for adequate blood pressure, that the heart cannot handle the demand. The addition of nitroglycerin and its vasodilating effects on an already overtaxed myocardium has and, in future situations, could cause cardiac arrest.
Letter from Pfizer Inc.
Pfizer Inc. is the pharmaceutical company that discovered and developed Viagra. On May 22, 1998, A Dear Doctor Letter was printed in the FDA MedWatch News. The letter was written to emergency physicians throughout the country from the medical director for the Sexual Health Team of the U.S. Pharmaceuticals Division of Pfizer Inc. The letter was written to emergency physicians to warn them that the inadvertent combination of Viagra and organic nitrates could occur, especially in the treatment of anginal episodes. It listed several possible scenarios when the inadvertent combination might occur:
(1) A man combines a nitrate and Viagra at home because of chest pain and becomes severely hypotensive and is brought to an emergency department.
(2) A man with no history of angina takes Viagra, engages in sexual activity and develops his first angina episode. This patient could be transported to an emergency department while having chest pain and a short-acting nitrate might routinely be administered for treatment.
(3) Although we have not specifically studied this, we believe that nitrates that are inhaled for recreational use (including amyl nitrate/nitrite or "poppers" and others) will have the same effect when combined with Viagra).
"Poppers" (amyl nitrite vaporoles) have an abuse potential, as they are vasodilators that have been used to prolong orgasm.
How Viagra is changing lifestyles
One only needs to access the Viagra Web site briefly to see the impact the new-found sexuality is having on some Viagra users. The pages of the Web site are replete with pornography and sex paraphernalia, as well as testimonials and enticing stories of revived virility. While the drug has revitalized the romance in perhaps millions of marriages, in others it has been a detriment to the marriage. The Viagra package insert clearly states that there are no ingredients in Viagra that provide protection against sexually transmitted diseases. Still the enticing stories on the Web site indicate that some Viagra users are living it up and making up for lost time.
Are they using Viagra?
There are special concerns for patients on Viagra that must be emphasized to dental professionals. The first order of importance is finding out if a patient is taking Viagra. Because Viagra is prescribed for erectile dysfunction in men, it can be quite embarrassing for men to admit that they are taking it, and a dental office might seem like a place where withholding the information would be quite innocuous. From the patient`s point of view, dental treatment and impotence treatment are hardly related. And much to our chagrin, many patients still perceive the oral cavity as a separate entity from the rest of their body, so we still have difficulty getting a complete medical history from such patients.
The greatest reason we need to know if a patient is taking Viagra is for preparation for the medical emergency, chest pain. In emergency care, all first-time chest pain is treated as a suspected heart attack. Chest pain in patients taking Viagra must not be treated with nitrates, such as nitroglycerin, as a pain reliever and/or differential diagnosis of myocardial infarction. The vasodilating properties of the nitrates coupled with the vasodilating effects of Viagra can cause severe low blood pressure that causes increased demand on the myocardium, leading to a heart attack and cardiac arrest.
Emergency medical technicians and paramedics are being told to question every patient experiencing chest pain as to whether they are or have taken Viagra. If the patient has taken Viagra, nitrates are not to be administered for emergency management of chest pain. Supplemental oxygen and basic life support are the recommended treatments for chest pain in dental patients being cared for by dental professionals.
Severe chest pain may be managed by various pain relievers prescribed by
emergency-care physicians. It is recommended that any male who is experiencing chest pain be questioned about taking Viagra at the time of the symptoms. Even if the patient denied taking Viagra at an earlier appointment in a routine medical-history questioning, the patient must be questioned again at the time of chest-pain symptoms.
Do not assume that younger men would not be taking Viagra. Impotence can be due to psychogenic etiology, and Viagra has been very effective in treating impotence of this type. Do not assume that younger men cannot have heart attacks. First-time chest pain, that persists for more than three minutes should be treated as a suspected heart attack in any individual.
It is important for all dental professionals to be knowledgeable about such widely prescribed medications as Viagra. As health professionals we are also educators, and many opportunities to share medical information are presented to dental professionals. When a patient notices an appointment with you has been very informative, you bring tremendous credit to the profession. Small talk about the weather is nice, but having current information of interest to patients is intellectually stimulating for you and your patients.
References
Y Viagra - Product Package Insert, 1998
Y The 1998 VirSci Corporation PharmInfoNet
Y FDA Summary of Death Reports - MedWatchNews, July 22, 1998
Y Siegal, RL, Letter to the Doctor, Pfizer?s Medical Information Department
Y www.viagra.com
Y Medical Sciences Bulletin, The Internet-Enhanced Journal of Pharmacology and Therapeutics, Issue No. 247 (April, 1998)
Cynthia R. Biron, RDH, is chair of the dental hygiene program at the Tallahassee Community College. She is also a certified emergency medical technician.
