Consumer stampede: How to counsel physicians, patients on Viagra
June 1, 1998
Consumer stampede: How to counsel physicians, patients on Viagra
Anticipating the problems before they hit the ER door
The National Institutes of Health estimates 30 million American men suffer from impotency, clinically termed erectile dysfunction (ED), and if it seems like all 30 million have been clamoring for Pfizer's breakthrough pill, Viagra, it's probably because they are.
In the first two weeks after the drug became available in mid-April, 36,809 prescriptions were dispensed, crushing the numbers for other high-demand lifestyle drugs that recently have come to market.
With prescriptions approaching 10,000 a day, the sheer numbers of potential patients are overwhelming urologists. Than means the overflow will spill into the offices of primary care physicians, so clinical pharmacists can expect to be called frequently for counseling on Viagra's pharmacotherapy.
A pharmacist's perspective
That counseling can be complex. Although generally considered safe, Viagra is contraindicated for patients taking nitrates because it boosts the hypotensive effects of those drugs. Careful patient screening is imperative, especially given that impotence often is the result of an underlying disease state such as heart disease or diabetes.
With the fen-phen fiasco still fresh in our minds, caution is probably a good watchword for a new drug with no long-term track record, some pharmacists say. "I don't know if there's the potential for this to be the next fen-phen, but you are going to see ubiquitous use for Viagra," predicts Thomas Burnakis, PharmD, pharmacy clinical coordinator at Baptist Medical Center in Jacksonville, FL.
He says the lure of fast and easy money will be too hard for some clinics to refuse. "Prescribing Viagra is going to be a money-making procedure. They'll give a cursory exam, charge you for that, and write the prescription. There are four or five impotency clinics in this town, and they're already advertising," Burnakis says.
Viagra, known generically as as sildenafil, is a phosphodiesterate type 5 (PDE5) inhibitor, which works by suppressing the enzyme PDE5, which causes erections to wane following ejaculation by diluting cyclic GMP, the body chemical that begins the vascular changes leading to erection. Cyclic GMP is produced only during stimulation, and in physically impotent men, not enough cyclic GMP is produced to offset the effects of PDE5.
"Other drugs affect the blood flow to the urethra, and this does that," says Burnakis, "but by opposing an enzyme that would normally constrict the vessels, Viagra opens the vessels by an indirect action." Viagra started out as an investigational drug to treat angina, but in the course of those trials, the drug's effects on impotency were discovered.
Some side effects are dangerous
Viagra trials of 4,000 men included those diagnosed with mild, moderate, or complete ED; their ages ranged from 20s to 80s. The NIH reports that one in four men with ED are over 65, while one in 20 are between 40 and 65. The trials also included men with ED-related conditions like hypertension, hyperlipidemia, and diabetes. The most common side effects reported included headache, flushing, dyspepsia, nasal congestion, some urinary tract infection, diarrhea, dizziness, and rashes.
"There is the risk of a transient change in vision, making it hard to see blue and green," Burnakis says, "but again, the biggest caution so far is not to use it with other nitrates. Angina patients, people with hypertension or a history of myocardia infarction, this is the group that might have some problems. How Viagra interferes with the metabolism is the worry, but chances are it's not going to be a big problem because it's unlikely people will be on this drug on a regular basis. It's as needed and it's expensive." The retail price is averaging $8 to $10 a pill.
And for now, Burnakis is willing to give the drug its due, stressing that pharmacists should continue to "err on the side of caution" when involved with prescriptions or patient counseling.
"This is a fairly remarkable drug," he allows. "We have looked at a lot of things that generally work for 30% to 40% of those who try it, but with Viagra, the studies report success up to 70% or even 80% of the cases, and that's a remarkable number."
A urologist in the trenches
Urologist John Stripling, MD, wrote 300 prescriptions for Viagra the day it became available during the second week of April. Soon after, he was still writing 25 to 35 scripts a day and fielding 45 to 50 calls at the Stripling Center in Atlanta, where he's been working with impotent men for 20 years.
"In the process of talking to patients about it as an alternative, and with the press the drug received beforehand, I had built up a list of over 300 patients who wanted to try it as soon as it came out," he says.
His patients run the gamut from elderly men who have lost much of the ability to sustain an erection, to a 20-year-old diabetic patient. "There are underlying disease states causing impotency, along with purely psychological factors," he says.
But at the same time, the drug's popularity has forced Stripling to face ethical issues that make fellow health care professionals like Burnakis wary. "In the last two weeks, two patients on nitro who wanted Viagra so bad have gotten off nitro patches [used for cardiac care] to get Viagra. The concern is these patients would not be getting enough oxygen to the heart, along with the worry that sex would be too strenuous. But it reflects the motivation these men have. I've had to talk to three cardiologists to determine whether to proceed, and that's going to be a difficult decision for cardiologists to make," he says.
In those cases, the patients were allowed to switch. Clinical trials have shown that substituting one form of nitroglycerin for another is much safer than allowing patients to take both. In the drug's trials, half of the patients on both nitrates passed out from sudden drops in blood pressure.
Another issue Stripling faces is how to deal with men who want Viagra for all the wrong reasons. Screening patients is difficult and often a judgment call, he warns. "I've had a number of calls from men who want to enhance their performance. Impotence can be somewhat subjective depending on your satisfaction, and you have to make the call on whether they are impaired enough to prescribe."
Like Burnakis, Stripling is impressed by the drug so far and has been promoting it. "In 20 years of practice, I've never seen a drug like this, with this much interest. Those with mild to moderate dysfunction will get great results, and we'll probably see a drop in injection therapy."
Stripling also doubts that Viagra could become the next health care dream turned nightmare like fen-phen. "Viagra has had an extremely safe profile, with side effects less than 3%, the most being headache, nausea, and runny nose. So I'm really optimistic."So far, he says, just a fraction of his patients have reported disappointing results.
"Most impressive in the studies was that every man had some type of improvement, and the best results were in the psychological group, those with relationship or identity problems or with issues of performance anxiety and stress."
He adds, however, that Viagra won't be a panacea. Patients needing penile implants or with the most severe damage, about 8% to 10% of all ED patients, may not respond to Viagra. He cautions that it's more important for pharmacists to investigate a patientknown medical history while screening for any unknown disease states.
"The problem is that usually impotency is a first sign of an underlying medical problem that could be missed, and there are side effects and interaction dangers if there is an underlying disease," he says. Pharmacists should screen for sickle-cell anemia, leukemia, and lymphoma.
Viagra's effect lasts four or five hours, meaning that subsequent erections can be achieved with further stimulation. Viagra's label states the drug can be taken "as needed," with ingestion recommended 30 to 40 minutes before sex. The drug is available in 25, 50, and 100 mg strengths. Stripling recommends a 50 mg initial dose and is prescribing between 10 and 30 pills per patient per month.
"You are not supposed to take it more than once every 24 hours because there can be too much additive effect. Bad side effects are dose-related," he says. "My other fear is people could get this drug bogusly and try to enhance themselves by using prostaglandin and Viagra together. Americans have this mentally that if one's good, five is better."
[For more information, contact: Pfizer Inc., 235 E. 42nd St., New York, NY 10017. Telephone: (800) 438-1985. Thomas Burnakis, PharmD, Pharmacy Clinical Coordinator, Baptist Medical Center, 800 Prudential Drive, Jacksonville, FL 32207. Telephone: (904) 202-2857. John Stripling, MD, The Stripling Center, 1459 Montreal Road, Tucker, GA 30345. Telephone: (770) 493-7255.]
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