Le Ricette di Casa Russo
is levitra better than cialis or viagra
Boston University Medical Campus
Sexual Medicine
Choosing the Right Pill to Treat ED
Ricardo Munarriz, MD
The most common sexual dysfunctions in men include lack of interest, premature ejaculation and erectile dysfunction. The latter affects 52% of men between the ages of 40 and 70, including mild, moderate and complete forms of ED.
Organic or physical causes for sexual dysfunction in men include vascular, hormonal and neurologic factors. Concerning vascular causes, the risk factors for atherosclerosis (including smoking, high blood pressure, diabetes (diabetics do not respond well to pills like sildenafil (Viagra)) and high cholesterol are ALSO risk factors for erectile dysfunction. Since a straddle injury or use of a narrow saddle can obstruct and impair arteries to the penis, bicycle riding is also considered a risk factor for erectile dysfunction.
Little attention has been paid to endocrine factors. Testosterone modulates desire, arousal and orgasmic function. Concerning the orgasmic response, testosterone modulates the integrity of genital sensory receptors. Concerning the arousal response, decreased testosterone blood levels can influence the efficacy of sildenafil (Viagra). If the sildenafil response is not reliably improving erection, the physician should first check if the patient is taking the pill correctly. The physician should also check the patient’s testosterone level. One investigator in Italy gave testosterone to patients with low testosterone who did not respond to sildenafil (Viagra). When daily testosterone was given, subsequent sildenafil (Viagra) use resulted in IIEF (the International Index of Erectile Function questionnaire used to determine erectile function) scores improving significantly.
Other risk factors for erectile dysfunction include neurologic problems (multiple sclerosis, stroke), depression and medications for treating diabetes, hypertension, heart disease and depression.
There are many oral therapies for erectile dysfunction, but the only approved medication in the US is the PDE 5 enzyme inhibitor sildenafil (Viagra). Unapproved therapies, some of which are available in the US and some elsewhere, some of which have data to prove efficacy and some not, include tadalafil (Cialis), vardenafil (Levitra), yohimbine, phentolamine, trazodone, apomorphine and neutraceuticals. PDE5 inhibitors act to relax penile erectile tissues with sexual stimulation thus enhancing your ability to get an erection. Sildenafil (Viagra) is effective for all sorts of erectile dysfunction in 69% of people. Why is there a need for another pill? In some cases the erection is not hard enough, sometimes sildenafil (Viagra) just doesn’t work.
Structurally vardenafil (Levitra) is similar to sildenafil, while tadalafil (Cialis) is very different. Vardenafil (Levitra) is almost 10 times more biochemically potent than sildenafil, therefore a lower dose is needed to facilitate the penile erection, potentially resulting in less side effects. Selectivity is the ability of the drug to attach to the specific enzyme PDE 5 found in penile tissues. Vardenafil (Levitra) is more selective than sildenafil and tadalafil (Cialis) to PDE5, which again means a lower dose is needed with potentially less side effects. Tadalafil is very specific for PDE5 and is also very specific for the enzyme PDE11. Unfortunately, we don’t know much about PDE11, which is found in the heart, in the pituitary gland in the brain and in the testicles. Pharmacokinetics, half-life, is how long the medication stay s in the blood. Sildenafil (Viagra) has a half-life of 4 hours and vardenafil (Levitra) has a half-life of 4-6 hours while tadalafil (Cialis) has a half-life of 17.5 hours. This means that vardenafil (Levitra) should act longer than sildenafil (Viagra) but the clinical significance is not known. Tadalafil (Cialis) has the longest half-life and allows you to take the medication and not relate the sexual activity to the immediate use of the medication. The drawback is if you need nitrates after using tadalafil (Cialis), this medication lasts a long time in your blood stream and may place you at a higher risk. Younger people might do well treated with tadalafil, (Cialis) while older people with other health issues might be better off using sildenafil (Viagra) or vardenafil (Levitra) but more data are needed. The side effects of vardenafil (Levitra) are potentially less than sildenafil (Viagra), but more data are needed. In a recent study on men with erectile dysfunction and diabetes, vardenafil (Levitra) improved their erectile dysfunction. Tadalafil (Cialis) is as effective as sildenafil (Viagra), and vardenafil (Levitra) with similar side effects except for back pain that occurs occasionally with tadalafil, probably because of the long half-life.
Many people stop taking drugs because they are experiencing side effects, they no longer have a partner, or they are worried about safety. Sexual activity is not a major contributor to the risk of a heart attack. Sexual activity, with or without sildenafil (Viagra) increases the chance of an MI during sexual activity by only 0.1%. If pills fail, there are vacuum devices, Muse, injections, bypass surgery and implants.
The patient making a presentation has had penile bypass surgery. In addition he takes testosterone and sildenafil as needed. This is a classic example of why people with ED need complete care: a psychological exam, history and physical exam, and diagnostic studies with long term follow-up care. Patients with ED should not just be prescribed sildenafil (Viagra) and then be lost to follow-up.
Viagra Vs. Levitra
Call it getting a rise out of the competition. In its first month of sales, Levitra, the new erectile dysfunction treatment from Bayer and GlaxoSmithKline. managed to grab a 50% share of prescriptions in newly diagnosed patients. Sounds impressive, but analysis by Bernstein Research of data from health information provider IMS Health reveals another side to these figures. Viagra maker Pfizer still has well more than 95% of total prescriptions for impotence.
Worse, Bernstein pharmaceuticals analyst
Richard Evans Richard Evans
sees U.S. sales of only $425 million each annually for Levitra and another erectile dysfunction drug, Cialis, being developed by Eli Lilly and ICOS. Cialis is expected to go on the market early next year. Viagra, which now has U.S. sales of $1 billion, will, by Evans’ reckoning, drop by nearly half. The new drugs will merely cannibalize the existing market.
Not everyone is so bearish.
Myron Murdock Myron Murdock
medical director of hisandherhealth.com and a doctor who has conducted clinical trials with all three drugs, thinks the flood of direct-to-consumer ads will get men into their doctor’s office. All three drugs work by inhibiting the same enzyme, but he sees significant advantages to the new entrants. Levitra is a more potent molecule, and it seems to work faster and on a full stomach. (Expect more studies from Pfizer, showing that Viagra works fast and with food, to keep up.) He says Levitra also clearly works better in hard-to-treat cases, such as men whose impotence is caused by diabetes.
Cialis, on the other hand, clearly works for 36 hours or more, making it an ideal choice for men who are very sexually active, Murdock says. He still gives Viagra the edge in treating female sexual dysfunction, a yet-unapproved but potentially lucrative use. Pfizer is five years ahead of the competition in that area. Murdock also notes another advantage for Levitra. Viagra patients have been ordering high-dose pills and splitting them, because all doses come at the same cost. Levitra, a small, hard orange pill, is much more difficult to cut, so at least it won’t have to deal with sales reduced by pill splitting.
ED Medications: Cialis, Levitra, Viagra
How do these drugs work?
Cialis, Levitra (Vardenafil) and Viagraв„ў (Sildenafil) work by selectively inhibiting an enzyme in the penis called Phosphodiesterase V (PDE V), a chemical that takes away the erection. By blocking PDE V temporarily, these medications empower the chemical, Nitric Oxide (NO) that occurs naturally with arousal to initiate, produce and maintain an erection. Patients need sexual stimulation and foreplay to release NO initiate an erection in order for these medications to be effective. They are called phosphodiesterase inhibitors.
This class of medication is a safe and effective oral treatment for men with erectile dysfunction of physical, psychological or mixed cause. However, it is important that patients should be aware of the low probability (less than 50%) that intercourse will be possible after the first dose - particularly in severe or advanced cases and especially when using Viagra or Levitra. The majority of men who stop Viagra because of apparent lack of effect will in fact respond and achieve intercourse if they continue to try again, progress from 50 mg to 100 mg, or take the pill without food on an empty stomach (3 hours after eating). Taking Viagra or Levitra on a full stomach will not only reduce their peak concentration in the body by 30 to 50% but in addition will delay their peak concentration by one hour. In other words one may have to wait after intake before initiating sexual activity. Cialis peak concentration and time before reaching maximum absorption is not affected by a full stomach. Because of this it remains my drug of choice for the treatment of ED and I always prescribe it first. In addition many of my patients experience fewer side effects with Cialis then with the other two. Finally Cialis has a long period of activity and patients are successful at intercourse up to 36 hours after taking this pill. This represents a distinct advantage from the patient’s perspective as it diminishes the need for planning. Sex can be more spontaneous and natural. Planning kills the mood. Having sex long after taking the pill makes men feel more normal! For these reasons I will first try Cialis on all my Patients and reserve Viagra and Levitra for those men who do not tolerate Cialis.
The steps illustrated in Reference #4 below will help optimize the chances of success of Levitra and Viagra 4.
Reliable safety data gathered in the 10 years since these PDE % inhibitors were launched confirm that side effects such as Priapism (prolonged erection), red eyes, painful eyes, syncope(fainting), tachycardia (rapid heart rate), and nausea do occur, but are rare. Back pain and muscle aches occur rarely with Cialis. HIV medications (protease inhibitors) have been shown to raise their blood levels. Certain patient groups are more susceptible to a decrease of their blood pressure, including those with aortic stenosis, hypertrophic obstructive cardiomyopathy, and multiple system atrophy. Finally, all PDE 5 inhibitors remain contraindicated in patients taking nitrates.
A few new safety concerns such as visual and hearing loss have emerged in the past year, however these remain extremely rare reinforcing that these medications are very safe. Indeed, we now know that many patients with cardiovascular disease (CVD) and ED benefit from it.
Erectile Dysfunction: Oral Therapy Treatment Options
Dr. J. Francois Eid discusses the oral therapy options, or "pills", available to treat erectile dysfunction.
The following can be prescribed a PDE 5 inhibitor (Cialis, Levitra, Viagra) safely without the need for extensive Cardiovascular investigationВІ:
Cialis (Tadalafil)
Oral medications such as Cialis, Levitra and Viagra are available for the treatment of erectile dysfunction. They are in a class called PDE 5 inhibitors. They work to restore a normal system of blood flow in the penis so that an erection can occur with sexual stimulation.
Highlights of Cialis:
Only ED medicine clinically proven to work up to 36 hours.
Works as fast as 30 minutes in some men.
Gives you the freedom to choose the moment that is right for you.
The most common side effects include headache, upset stomach, back pain and muscle aches. The side effects usually go away after a few hours. In the rare event of Priapism seek immediate medical help to avoid long term injury. Another uncommon side effect reported was a sudden decrease or loss of vision.
Who should not take Cialis:
Cialis is contraindicated in patients using nitrates. If you use recreational drugs called “poppers” like amyl nitrate and buty nitrite do not take Cialis. If Cialis is taken with certain Alpha Blockers, it can result in a sudden drop of blood pressure, which could lead to dizziness or faintness. It can however be used with Flomax 0.4mg.
Tell your doctor if you take any other medications including prescription and non-prescription medicines, vitamins or any health supplements as Cialis and these may affect each other adversely.
How to use Cialis:
Cialis is available by prescription only. It is taken orally before sexual activity, not more than once daily. It may be taken with or without food. In some patients, the dose strength and maximum frequency of use may be adjusted.
Levitra (Vardenafil)
Levitra is also an FDA approved medication for the treatment of Erectile Dysfunction.
How Levitra works:
Levitra is an oral medicine, available by prescription only, and should be taken approximately 60 minutes prior to sexual activity. It should be taken no more than once daily. It can be taken with or without food.
The side effects are generally mild and do not last very long. The most common side effects are headache, flushing, stuffy or runny nose. In rare cases Priapism and vision changes have been observed.
Levitra is contraindicated in patients who take any form of medication known as nitrates or recreational drugs called “poppers” like amyl nitra or butyl nitrate. If you are taking any alpha blockers, Levitra is not the right medication for you.
First effective FDA-approved oral medication for the treatment erectile dysfunction
Boosts natural process of erection during arousal
Works across broad range of Erectile Dysfunction causes
Over 6 million patients have tried it
Approximately 250,000 doctors have prescribed it
Over 14 million prescriptions written
Over 100 million tablets dispensed
Unlike placebo-like drugs, Viagraв„ў has high refill rate
How to Use Viagraв„ў
If taken on an empty stomach, it takes about 85 minutes for Viagraв„ў to be absorbed into the circulation and reach the penis. Some patients (younger men) may experience benefits from the medication as early as 30 minutes after taking it. A high fat meal will delay the absorption of Viagraв„ў, and therefore it is recommended that Viagraв„ў is taken on an empty stomach or after a lowfat meal. Furthermore, once absorbed, Viagraв„ў will stay in the circulation for approximately four to six hours, which represents the window of sexual opportunity. If initially not successful, patients should try Viagraв„ў at 100mg on 3 different occasions before concluding that the medication is ineffective.
Viagraв„ў is effective in two-thirds of men with erectile dysfunction regardless of age and the severity of Erectile Dysfunction. However, certain groups of men using the drug do better than others. For example, spinal cord injured males have better results than patients suffering from cardiovascular disease (e.g. hypertension, high serum fat levels), and patients who have undergone treatment for prostate cancer (e.g. removal of the prostate or radiation therapy) seem to benefit the least.
Viagraв„ў Side Effects
Most side effects are mild and well-tolerated. The following are the most common reported side effects: headache, flushing of the face, heartburn, and nasal congestion. A small percentage (3%) of people may develop visual disturbance; it may take the form of a blue haze or tinge as well as increased perception of brightness. This effect is very mild, transient, and reversible.
Who Should Not Take Viagraв„ў
Viagraв„ў is CONTRAINDICATED for patients who take any medications that contain nitrates. This includes patients who need nitrates (including nitroglycerine) on an intermittent basis for the treatment of angina.
In patients used to regular exertion, sexual activity poses no special cardiovascular risk. Even in patients who have a history of myocardial infarction (MI), there is little risk of MI during intercourse for those who exercise regularly. However, there is insufficient information on the cardiovascular risk in previously sexually inactive men who become sexually active. Stress test and/or referral to a cardiologist may be appropriate, and variables such as patient's age, medical history and existing medical conditions may be relevant.
Stendra
Alternative medication therapies
Alternative oral therapies for Erectile Dysfunction (availability may vary geographically) are Uprima (apomorphine), and phentolamine. Both Uprima and phentolamine have very low or no efficacies and therefore for present purposes will not be addressed.
Uprima is approved for the treatment of Erectile Dysfunction in Europe and initial sales have not been very impressive (less than 20% of ED market). Refill rates are dismal supporting lack of efficacy.
Phentolamine’s application to the FDA was withdrawn and the drug is not available.
Discussion
Although Viagra, Levitra and Cialis differ in their biochemical potency and selectivity, and in onset and duration of action, it is important not to extrapolate those findings inappropriately to the clinical setting. For example, greater biochemical potency does not necessarily translate into enhanced clinical efficacy. The same is true of selectivity. In short, there appears to be little biochemical or clinical differences between the three agents except for the lack of food interaction and the duration of activity for Cialis. All three medications are contraindicated in patients who take nitrates.
A recent survey looking at what patients with ED really want from their treatment found that efficacy and a favorable side-effect profile were the highest prioritiesВі Fast onset was desirable, but there were major differences in what was considered fast. Duration was important only in terms of lasting long enough to complete intercourse. Few men (or their partners) felt that multiple erections, or the ability to achieve them over time, were critical as long as one dose was enough for a successful encounter. Most complaints were about high cost or lack of insurance coverage.
An underlying desire was reported by most couples for initiation of sex to be normal (spontaneous and natural). Few patients fully understood the duration of activity that Viagra can provide, and its advantages. Cialis may indeed fulfill the desire that couples and patients with ED have for the initiation of sex to be normal (spontaneous and natural). Although Viagra, Levitra and Cialis are safe and effective they do, like all medications, have disadvantages. They essentially enhance partial (sexual) erections, rather than initiating them. At best, the response rate among men with advanced ED (for example following radical prostatectomy) is 30%. Fewer than 505 of men with Diabetes will respond. Correct administration of Viagra and Levitra is critical, and if one does not work when taken correctly, no other oral “Viagra like drug” (PDE5 inhibitor like Levitra or Cialis) will either.
In conclusion, the potencies of Viagra, Levitra and Cialis are broadly similar, but each has unique pharmacological properties related to its molecular structure. Viagra is an exemplary PDE-5 inhibitor that, after 10 years of widespread clinical use, is acknowledged to be effective and particularly well tolerated. Cialis and Levitra are the newer medications and are similar to Viagra in their efficacy and contraindications. The only new attributes of clinical significance are the lack of food interaction and the long duration of action of Cialis. This may translate into greater efficacy of the first dose as well as a return to more spontaneous (normal) initiation of sexual activity (broader window of opportunity).
Question: Is it possible to identify potential non-responders to oral therapy?
Answer: No, it is not possible to identify potential non-responders to a PDE 5 inhibitor such as Cialis, Levitra or Viagra, other than by a trial of these medications in the setting of sexual activity. Patients, who appear to be non-responders to Viagra or Levitra, need to repeat a trial on an empty stomach a few different times before giving up. Cialis absorption and onset of action is not affected by food. The 20-30% who still do not respond generally have ED related to an irreversible physical abnormality due to chronic poor blood flow (often smoking-related) or damaged penile tissue (often diabetes, high cholesterol and after prostate cancer surgery). The best option for these patients remains an inflatable penile prosthesis.
Question: You said that the PDE5 inhibitors were comparable in efficacy. What about reports that Levitra is more effective than Viagra in treating ED among men with diabetes?
Answer: Clinical trial reveals that all three medications have the same success regardless of patient age, underlying medical condition or severity of erectile dysfunction. There is no head-to-head evidence of that, and what literature there is may be misleading. My belief is that clinical experience will show them to be similar.
References
McCullough AR, et al. J Urol 2001. In press.
- men who require fast onset or better absorption should avoid fatty meals or take these pills on an empty stomach;
- maximize sexual stimulation and arousal;
- start foreplay later in older patients (who may need up to 2 hours to absorb the medicicne);
- consider partner issues;
- do not give up before making at least 3 attempts at intercourse having at the maximum dose: Viagra 100 mg, Levitra 20mg.
