In December 1992, The National Institute of Health (NIH) defined impotence as “male erectile dysfunction, that is, the inability to achieve or maintain an erection sufficient for satisfactory sexual performance.
The prevalence of erectile dysfunction is anticipated to increase from 152 million in 1995 to 322 million by 2025. Levitra is the brand name of Vardenafil.
Vardenafil is a phosphodiesterase type 5 inhibitor used in the treatment of erectile dysfunction in men mostly middle-aged.
Levitra is available as film-coated tablets (5, 10 and 20 mg) and as orodispersible tablets (10 mg).
In March 2003, Levitra received the marketing authorization from the European Commission and also from regulatory authorities in several Latin America countries.
What is erectile dysfunction?
Erectile dysfunction represents the persistent inability to attain and maintain an erection sufficient to permit satisfactory sexual performance for at least 3 months. Erectile dysfunction has a significant impact on the physical and psychological health of men worldwide and can also affect the quality of life of both the sufferers and their partners.
Multiple body systems are involved in the pathophysiology of erectile dysfunction, including neuronal, hormonal, mechanical and psychological.
Penile erection is a complex phenomenon which involves a delicate and coordinated balance between neurological, vascular and tissue compartments. This includes arterial dilatation, relaxation of the trabecular smooth muscle, and activation of the corporeal venous-occlusive mechanism.
The risk of erectile dysfunction may be increased by the following:
Smoking: it increases the risk of impotence by reducing the blood flow to the penis.
Being overweight: extra pounds may lead to the occurrence of blood vessel disease which is considered a cause of erectile dysfunction.
Inactive lifestyle: the chance if getting erectile dysfunction may be reducing by regular exercises.
Poorly managed diabetes: diabetes can affect blood flow to your penis.
High cholesterol: it can damage the linings of blood vessels, including those in the penis and it can also affect the arteries leading to your genitals.
Alcohol: more than two drinks a day may have a bad influence on your ability to get an erection. Alcohol restricts blood flow to the penis and can hinder the production of testosterone. Low testosterone can affect not only your performance but your desire, too.
Illegal drug use: Marijuana, cocaine, and other recreational drugs can cause erectile dysfunction by damaging blood vessels. They can also restrict blood flow to the penis.
Stress and anxiety: they may lead to temporary erectile dysfunction.
Medical conditions which can cause erectile dysfunction
The following diseases may lead to the occurrence of erectile dysfunction:
Vardenafil mechanism of action in erectile dysfunction
Like other phosphodiesterase types 5 inhibitors, Levitra is not effective in the absence of sexual stimulation. Levitra acts by increasing the blood flow in the penis and improves the erectile function in men with erectile dysfunction.
Vardenafil is a potent and selective inhibitor of the cyclic guanosine monophosphate-specific phosphodiesterase type 5 (PDE5), the most prominent phosphodiesterase in the human corpus cavernosum responsible for degradation of cyclic guanosine monophosphate. During sexual stimulation, the release of nitric oxide from nerve terminals and endothelial cells determinates the relaxation penile arteries and corpus cavernosa smooth muscle by increasing the penile blood flow. The release of nitric oxide stimulates the synthesis of cyclic guanosine monophosphate in the smooth muscle cells. The increased levels of cyclic guanosine monophosphate (cGMP), leading to smooth muscle relaxation in the corpus cavernosum, resulting in increased inflow of blood and an erection.
Pharmacokinetic profile of Levitra (Vardenafil)
During the bioequivalence studies, it was shown that vardenafil 10 mg orodispersible tablet is not bioequivalent to vardenafil 10 mg film-coated tablets; therefore, the orodispersible formulation should not be used as an equivalent to vardenafil 10 mg film-coated tablets.
Vardenafil film-coated tablets are rapidly absorbed with maximum observed plasma concentrations reached in some men as early as 15 minutes after oral administration. However, 90% of the time, maximum plasma concentrations are reached within 30 to 120 minutes (median 60 minutes) of oral dosing in the fasted state.
Administrated with high-fat meals (containing 57% fat), the rate of absorption of vardenafil film-coated tablets is reduced.
After oral administration of Levitra orodispersible tablets without water, the active ingredient is rapidly absorbed. The median time to reach the maximum plasma concentration varied between 45 to 90 minutes and was similar or slightly delayed (by 8 to 45 min) compared to the film-coated tablets.
Fat meals have no effect on the absorption of the orodispersible tablets; therefore vardenafil 10 mg orodispersible tablets can be taken with or without food.
If vardenafil 10 mg orodispersible tablets are taken with water, the AUC is reduced by 29%, Cmax remains unchanged and the median Tmax is shortened by 60 minutes compared to intake without water. Vardenafil 10 mg orodispersible tablets must be taken without liquid.
Levitra is distributed into tissues with a volume of distribution of 208 l.
Vardenafil and its major circulating metabolite (M1) are highly bound to plasma proteins (approximately 95% for vardenafil or M1). For vardenafil as well as M1, protein binding is independent of total drug concentrations.
Vardenafil in film-coated tablets is metabolised predominantly by hepatic metabolism via cytochrome P450 (CYP) isoform 3A4 with some contribution from CYP3A5 and CYP2C isoforms.
In humans, the one major circulating metabolite (M1) results from desethylation of vardenafil and is subject to further metabolism with a plasma elimination half-life of approximately 4 hours. Parts of M1 are in the form of the glucuronide in the systemic circulation. Metabolite M1 shows a phosphodiesterase selectivity profile like vardenafil and an in vitro potency for phosphodiesterase type 5 of approximately 28% compared to vardenafil, resulting in an efficacy contribution of about 7%.
The mean terminal half-life of vardenafil in patients receiving vardenafil 10 mg orodispersible tablets ranged between 4 – 6 hours. The elimination half-life of the metabolite M1 is between 3 to 5 hours.
The total body clearance of vardenafil is 56 l/h with a resultant terminal half-life of approximately 4-5 hours. After oral administration, vardenafil is excreted as metabolites predominantly in the faeces (approximately 91-95% of the administered dose) and to a lesser extent in the urine (approximately 2-6% of the administered dose).
Which are the side effects of Levitra?
Like all other drugs, Levitra can cause side effects, although not everybody gets them. Most of the effects are mild or moderate.
Very common side effects (may affect more 1 in 10 patients) include:
Common side effects (may affect up to 1 in 10 patients) include:
Blocked or a runny nose,
Uncommon side effects (may affect up to 1 in 100 patients) include:
Effects on vision; redness of the eye, effects on colour vision, eye pain and discomfort, light sensitivity,
Limitations of Levitra. Special warnings and precautions for use
Before starting the pharmacological treatment with Levitra, a medical history and physical examination should be undertaken to diagnose the erectile dysfunction and determine potential underlying causes.
Cardiovascular status of the patients should be considered by the physicians prior to initiating any treatment for erectile dysfunction because the cardiac risk is associated with sexual activity.
Due to its vasodilator properties, vardenafil leads to mild and transient decreases in blood pressure.
Vardenafil and other phosphodiesterase types 5 inhibitors are not recommended in patients left ventricular outflow obstruction.
Vardenafil should be used with caution in patients with the following conditions:
Anatomical deformation of the penis (such as angulation, cavernosal fibrosis or Peyronie’s disease);
Conditions which may lead to the occurrence of priapism (such as sickle cell anaemia, multiple myeloma or leukaemia).
Drug interactions of Levitra
Using vardenafil concomitant with alpha-blockers, symptomatic hypotension may occur in some patients because both drugs have vasodilators properties. Vardenafil can be administered with an alpha-blocker only if the patient has been stabilized on his/her alpha-blocker therapy. In those patients who are stable on alpha-blocker therapy, vardenafil should be initiated at the lowest recommended starting dose of 5 mg film-coated tablets.
Itraconazole and ketoconazole
Concomitant use of vardenafil itraconazole and ketoconazole oral form should be avoided because high plasma concentrations of vardenafil are reached if these drugs are combined.
Erythromycin and clarithromycin
Dose adjustment of vardenafil might be necessary if erythromycin and clarithromycin are given concomitantly.
Combination of vardenafil with grapefruit juice should be avoided because the grapefruit juice is expected to increase the plasma concentrations of vardenafil.
Levitra is contraindicated in the following situations:
hypersensitivity to the active substance or to any of the excipients;
co-administration of nitrates;
co-administration of ketoconazole and itraconazole (oral form) in men older than 75 years;
co-administration of HIV protease inhibitors such as ritonavir and indinavir;
co-administration of guanylate cyclase stimulators, such as riociguat;
patients who have loss of vision in one eye because of non-arteritic anterior ischemic optic neuropathy (NAION);
men for whom sexual activity is inadvisable (e.g. patients with severe cardiovascular disorders such as unstable angina or severe cardiac failure [New York Heart Association III or IV]);
severe hepatic impairment (Child-Pugh C);
end-stage renal disease requiring dialysis;
hypotension (blood pressure <90/50 mmHg)
a recent history of stroke or myocardial infarction (within the last 6 months)
unstable angina and known hereditary retinal degenerative disorders such as retinitis pigmentosa.
Facts that you should take into consideration before taking Levitra
Before taking Levitra, tell you should tell your doctor or your pharmacist if you suffer or ever suffered of:
heart problems such as angina, heart failure, irregular heartbeats, or have had a heart attack,
low blood pressure or have high blood pressure that is not controlled,
kidney problems and require dialysis,
retinitis pigmentosa, a rare genetic (runs in families) eye disease,
severe vision loss, or if you have an eye condition called non-arteritic anterior ischemic optic neuropathy (NAION),
deformed penis shape or Peyronie’s disease,
an erection that lasted more than 4 hours,
blood cell problems such as sickle cell anaemia, multiple myeloma, or leukaemia,
How should I take Levitra?
For most individuals, the recommended dose of vardenafil regular tablets is 10 mg per day taken 60 minutes before intercourse. If there is no response or side effects, the dose may be increased to 20 mg or, if there are side effects, it may be reduced to 5 mg.
Individuals 65 years of age or older should begin therapy with 5 mg.
Individuals who are taking medications that increase the blood levels of vardenafil should start treatment with 2.5 to 5 mg of vardenafil.
Orally disintegrating tablets are not interchangeable with regular vardenafil tablets because they are better absorbed and produce higher blood levels than regular tablets. The recommended dosing when using orally disintegrating tablets is one tablet 60 minutes before intercourse. Only one tablet should be used per day. It should be placed on the tongue until it disintegrates and should not be swallowed with water.
How can you get the most from your treatment?
Both you and your partner will still need to engage in foreplay. Like all other phosphodiesterase type-5 inhibitors, vardenafil will not cause an erection unless you are sexually aroused.
Do not drink large amounts of alcohol before you plan to take vardenafil. Drinking too much alcohol can reduce your ability to get an erection and this may prevent you from getting the maximum benefit from the tablets.
Do not drink grapefruit juice with vardenafil. The grapefruit juice can increase the amount of vardenafil in your bloodstream and make side-effects more likely.
Keep your regular appointments with your doctor so your progress can be monitored. If you feel the tablets are too strong for you, discuss this with your doctor as your dose may need to be reduced. Alternatively, if you do not get an erection after taking vardenafil, or if it does not last long enough for you to have sex, you should discuss this with your doctor – do not take more tablets than you have been told to.
Do not take vardenafil if you are using any other products or taking any other medicines to treat erectile dysfunction.
Assured Pharmacy is not liable for the currency or accuracy of the information contained in this blog post. For specific information about your personal medical condition, please contact our doctors or pharmacists for advice on [email protected]