Understanding Vardenafil for Erectile Dysfunction

The inhibitory effect of vardenafil is more selective on PDE5 than for other known phosphodiesterases (>15-fold relative to PDE6, >130-fold relative to PDE1, >300-fold relative to PDE11, and >1,000-fold relative to PDE2, 3, 4, 7, 8, 9, and 10). The pharmacokinetics of vardenafil are approximately dose proportional over the recommended dose range.

Conflicts of interest

^ "New erectile dysfunction treatment Staxyn approved in the U.S. - Pharmaceutical Processing". Archived from the original on April 6, 2012. ^ "Staxyn - New Innovation in Erectile Dysfunction Helps Younger Men Rise to the Occasion". U.S.

Pharmacology of phosphodiesterase-5 inhibitors

Food and Drug Administration (FDA). ^ Tucker J, Fischer T, Upjohn L, Mazzera D, Kumar M (October 2018). "Unapproved Pharmaceutical Ingredients Included in Dietary Supplements Associated With US Food and Drug Administration Warnings". LEVITRA- vardenafil hydrochloride tablet, film coated APHENA PHARMA SOLUTIONS - TENNESSEE, INC. LEVITRA® is an oral therapy for the treatment of erectile dysfunction. Vardenafil is eliminated predominantly by hepatic metabolism, mainly by CYP3A4 and to a minor extent, CYP2C isoforms.

Concomitant use with potent CYP3A4 inhibitors such as ritonavir, indinavir, ketoconazole, as well as moderate CYP3A inhibitors such as erythromycin results in significant increases of plasma levels of vardenafil (see PRECAUTIONS, WARNINGS and DOSAGE AND ADMINISTRATION).

Common Side Effects of Vardenafil

Store it at room temperature and away from excess heat and moisture (not in the bathroom). Dispose of unneeded medications in a way so that pets, children, and other people cannot take them. Do not flush this medication down the toilet. Talk to your pharmacist about take-back programs in your community. Visit the FDA's Safe Disposal of Medicines website for more information.

Key Takeaways

Keep all medication out of sight and reach of children as many containers are not child-resistant. Place the medication in a safe location – one that is up and away and out of their sight and reach. In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911. Do not let anyone else take your medication.

What should I do if I miss a dose of vardenafil?

Ask your pharmacist any questions you have about refilling your prescription. Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies. Vardenafil, sold under the brand name Levitra among others, is a medication that is used for treating erectile dysfunction. Mean vardenafil plasma concentrations measured after the administration of a single oral dose of 20 mg to healthy male volunteers are depicted in Figure 1. Figure 1: Plasma Vardenafil Concentration (Mean ± SD) Curve for a Single 20 mg LEVITRA Dose Vardenafil is rapidly absorbed with absolute bioavailability of approximately 15%.

Maximum observed plasma concentrations after a single 20 mg dose in healthy volunteers are usually reached between 30 minutes and 2 hours (median 60 minutes) after oral dosing in the fasted state.

Two food-effect studies were conducted which showed that high-fat meals caused a reduction in Cmax by 18%-50%.

• Storage should be at room temperature away from moisture.
• Keep Vardenafil out of reach of children and pets.
• Check expiration date before use.

The mean steady-state volume of distribution (Vss) for vardenafil is 208 L, indicating extensive tissue distribution. Vardenafil and its major circulating metabolite, M1, are highly bound to plasma proteins (about 95% for parent drug and M1).

How Vardenafil and Viagra Work

The cGMP in turn triggers smooth muscle relaxation, allowing increased blood flow into the penis, resulting in erection. The tissue concentration of cGMP is regulated by both the rates of synthesis and degradation via phosphodiesterases (PDEs). The most abundant PDE in the human corpus cavernosum is the cGMP-specific phosphodiesterase type 5 (PDE5); therefore, the inhibition of PDE5 enhances erectile fildena super active 100 function by increasing the amount of cGMP. Because sexual stimulation is required to initiate the local release of nitric oxide, the inhibition of PDE5 has no effect in the absence of sexual stimulation. In vitro studies have shown that vardenafil is a selective inhibitor of PDE5. This protein binding is reversible and independent of total drug concentrations.

How Effective is Vardenafil?

Vardenafil HCl is designated chemically as piperazine, 1-[[3-(1,4-dihydro-5-methyl-4-oxo-7-propylimidazo[5,1-f ][1,2,4]triazin-2-yl)-4-ethoxyphenyl]sulfonyl]-4-ethyl-, monohydrochloride and has the following structural formula: Vardenafil HCl is a nearly colorless, solid substance with a molecular weight of 579.1 g/mol and a solubility of 0.11 mg/mL in water. LEVITRA is formulated as orange, round, film-coated tablets with “BAYER” cross debossed on one side and “2.5”, “5”, “10”, and “20” on the other side corresponding to 2.5 mg, 5 mg, 10 mg, and 20 mg of vardenafil, respectively. Penile erection is a hemodynamic process initiated by the relaxation of smooth muscle in the corpus cavernosum and its associated arterioles. During sexual stimulation, nitric oxide is released from nerve endings and endothelial cells in the corpus cavernosum. Nitric oxide activates the enzyme guanylate cyclase resulting in increased synthesis of cyclic guanosine monophosphate (cGMP) in the smooth muscle cells of the corpus cavernosum. Following a single oral dose of 20 mg vardenafil in healthy volunteers, a mean of 0.00018% of the administered dose was obtained in semen 1.5 hours after dosing.

Vardenafil is metabolized predominantly by the hepatic enzyme CYP3A4, with contribution from the CYP3A5 and CYP2C isoforms. The major circulating metabolite, M1, results from desethylation at the piperazine moiety of vardenafil. The plasma concentration of M1 is approximately 26% that of the parent compound.

• Common side effects include headaches and flushing.
• Serious side effects are rare but may include vision changes.
• Consult a doctor if you experience chest pain.

This metabolite shows a phosphodiesterase selectivity profile similar to that of vardenafil and an in vitro inhibitory potency for PDE5 28% of that of vardenafil.

• Vardenafil may cause a fainting sensation in some users.
• Stay seated or lying down if dizziness occurs.
• Rise slowly from sitting or lying positions.

Therefore, M1 accounts for approximately 7% of total pharmacologic activity.

Vardenafil Warnings & Precautions

Vardenafil's indications and contraindications are the same as with other PDE5 inhibitors; it is closely related in function to sildenafil citrate (Viagra) and tadalafil (Cialis). The difference between the vardenafil molecule and sildenafil citrate is a nitrogen atom's position and the change of sildenafil's piperazine ring methyl group to an ethyl group. Tadalafil is structurally different from both sildenafil and vardenafil. Vardenafil's relatively short effective time is comparable to but somewhat longer than sildenafil's. Despite the structural differences between vardenafil and sildenafil, they both show similar ocular side effects due to their similar selectivity overlap with PDE6, an enzyme found in the eye.

Can I buy Levitra over the counter?

Beyond its indications for erectile dysfunction, vardenafil may be effective in the treatment of premature ejaculation, where it may significantly increase the time from penetration to ejaculation. The common, adverse drug reactions (side effects) are the same as with other PDE5 inhibitors. The frequent vardenafil-specific side-effect is nausea; the infrequent side effects are abdominal pain, back pain, photosensitivity, abnormal vision, eye pain, facial edema, hypotension, palpitation, tachycardia, arthralgia, myalgia, rash, itch, and priapism. One possibly serious, but rare, side effect with vardenafil is heart attack. Also, in rare cases, vardenafil use may cause priapism, a very painful emergency condition that can cause impotence if left untreated.

Viagra™ Efficacy

In October 2007, the U.S. Food and Drug Administration (FDA) announced that a warning about possible deafness (sudden hearing loss) would be added to the drug labels of vardenafil, cenforce professional 100 and other PDE5 inhibitors. Vardenafil should not be used by people taking nitrate medications, because combining them with vardenafil might provoke potentially life-threatening hypotension (low blood pressure). Further, vardenafil causes lengthening of the QT interval. Therefore, it should not be taken by people taking other medications that affect the QT interval (such as amiodarone). The total body clearance of vardenafil is 56 L/h, and the terminal half-life of vardenafil and its primary metabolite (M1) is approximately 4-5 hours.

Warnings & Precautions

Vardenafil was co-marketed by Bayer Pharmaceuticals, GlaxoSmithKline, and Schering-Plough under the brand name Levitra. As of 2005, the co-promotion rights of GSK on Levitra have been returned to Bayer in many markets outside the US. Thus, because of European Union trade rules, parallel imports might result in Vivanza sold next to Levitra in the EU. An orally disintegrating form, marketed as Staxyn and Levitra Soft, has been gaining approvals in countries such as the United States[11] and Canada. The US Food and Drug Administration (FDA) has found vardenafil and other synthetic PDE5 inhibitors in numerous products marketed as "herbal" supplements or "all natural" products for male enhancement.

Highlights of Cialis:

^ a b c d "Levitra stay hard pills (vardenafil hydrochloride) tablets, for oral use Initial U.S. Approval: 2003". ^ "Levitra (Vardenafil) is A Drug Used to Treat Erectile Problems in Men" (in German). "Potency, selectivity, and consequences of nonselectivity of PDE inhibition". "Effects of vardenafil administration on intravaginal ejaculatory latency time in men with lifelong premature ejaculation".

How Long Does Vardenafil Last?

"Counseling Patients About Sexual Issues: Drug-Induced Priapism". ^ "FDA Announces Revisions to Labels for Cialis, Levitra and Viagra". Archived from the original on July 9, 2009. "Pharmacology and drug interaction effects of the phosphodiesterase 5 inhibitors: focus on alpha-blocker interactions". "The QT Interval and Selection of Alpha-Blockers for Benign Prostatic Hyperplasia". After oral administration, vardenafil is excreted as metabolites predominantly in the feces (approximately 91-95% of administered oral dose) and to a lesser extent in the urine (approximately 2-6% of administered oral dose).