http://www.webmd.com/erectile-dysfunctio...a-treat-ed
WebMD:
What Are the Differences Between Cialis, Levitra, Staxyn, Stendra, and Viagra?
Cialis, Levitra, Staxyn, Stendra, and Viagra work by a similar mechanism to cause erections. There are subtle differences in how long the drug works and how quickly it works. Levitra works a little longer than Viagra. They both take effect in about 30 minutes. With Levitra, the effects last for about 5 hours. With Viagra, the effects last approximately 4 hours.
Cialis works a bit faster (within about 15 minutes), and the effects last much longer -- up to 36 hours in some cases. Stendra can start working in as little as 15 minutes and last up to 6 hours. Staxyn is an orally disintegrating tablet that contains the same active ingredient as Levitra but is not interchangeable with Levitra tablets.
If One of These Drugs Isn't Effective for Erectile Dysfunction, Can I Try Another?
Yes, but because these drugs work the same way, it's unlikely that you'll have success with one if you've failed to achieve an adequate erection with another.
What Precautions Should I Take Before Taking One of These Drugs?
There are certain situations in which these drugs may not be safe to take. Before taking them, tell your doctor:
If you are allergic to any drugs, including Viagra or other ED medications.
About any prescription or nonprescription medications you are currently taking, including herbal and dietary supplements.
If you are scheduled for surgery, including dental surgery.
If you take nitroglycerin or a long-acting nitrate to treat chest pain. The combination of Cialis, Levitra, Staxyn, Stendra, or Viagra with these drugs can cause dangerously low blood pressure.
If you take alpha-blockers for blood pressure or prostate problems. The combination of Cialis, Levitra, Staxyn, Stendra, or Viagra with these drugs can also cause dangerously low blood pressure. Patients should not be started on Staxyn unless they have previously taken Levitra as directed by their doctor.
In addition, always follow the directions on your prescription label carefully and ask your doctor or pharmacist to explain any part that you do not understand. Take these drugs exactly as directed. Do not take more or less or take it more often than prescribed by your doctor. Do not take these drugs more than once a day.
Who Should Not Take Cialis, Levitra, Staxyn, Stendra, or Viagra?
If you have suffered from a heart attack, stroke or life threatening arrhythmia (irregular heart rate) within the last 6 months you should discuss other options with your doctor. It is also advised to avoid these drugs if you have uncontrolled high or low blood pressure or if you experience chest pain with sex.
What Are the Side Effects of Cialis, Levitra, Staxyn, Stendra, and Viagra?
Side effects are not common but they can occur. Side effects can include:
Headache
Upset stomach or heartburn
Flushing (feeling warm)
Nasal congestion
Changes in vision (color, glare)
Back pain (with Cialis)
Call your doctor if you experience severe forms of these symptoms or if they do not go away after 4-8 hours.
Warning
Call your doctor or seek emergency treatment immediately if you experience any of the following symptoms:
Rash
Painful erection
Prolonged erection (longer than 4 hours)
Fainting
Chest pain
Itching or burning during urination
Stop taking these medications and call a doctor or health care provider right away if you experience sudden or decreased vision loss in one or both eyes. A rare vision problem called NAION has been reported by a few men using these drugs. NAION (nonarteritic anterior ischemic optic neuropathy) causes a sudden loss of eyesight because blood flow is blocked to the optic nerve. People who have a higher chance for NAION include those who:
Are over 50 years old
Smoke
Have heart disease
Have diabetes
Have high blood pressure
Have high cholesterol
Have certain eye problems
How Should These Drugs Be Stored?
These drugs should be kept in its original container and out of reach of children. Store them away from excess heat and moisture (not in the bathroom). Discard any medication that has expired or is no longer needed.
Further Reading:
PDR: http://www.pdr.net/drug-summary/levitra?...75&id=2112
Levitra
(vardenafil hcl) - Merck
THERAPEUTIC CLASS
Phosphodiesterase type 5 inhibitor http://en.wikipedia.org/wiki/PDE5_inhibitor
A phosphodiesterase type 5 inhibitor, often shortened to PDE5 inhibitor, is a drug used to block the degradative action of phosphodiesterase type 5 on cyclic GMP in the smooth muscle cells lining the blood vessels supplying the corpus cavernosum of the penis. These drugs are used in the treatment of erectile dysfunction, and were the first effective oral treatment available for the condition. Because PDE5 is also present in the arterial wall smooth muscle within the lungs, PDE5 inhibitors have also been explored for the treatment of pulmonary hypertension, a disease in which blood vessels in the lungs become overloaded with fluid, usually as a result of failure of the left ventricle of the heart.
Mechanism of action
Part of the physiological process of erection involves the release of nitric oxide (NO) in vasculature of the corpus cavernosum as a result of sexual stimulation. NO activates the enzyme guanylate cyclase which results in increased levels of cyclic guanosine monophosphate (cGMP), leading to smooth muscle relaxation in blood vessels supplying the corpus cavernosum, resulting in increased blood flow and an erection.
PDE5 inhibitors inhibit the degradation of cGMP by phosphodiesterase type 5 (PDE5), increasing bloodflow to the penis during sexual stimulation.
This mode of action means that PDE5 inhibitors are ineffective without sexual stimulation.
Cyclic guanosine monophosphate (cGMP) is a cyclic nucleotide derived from guanosine triphosphate (GTP). cGMP acts as a second messenger much like cyclic AMP. Its most likely mechanism of action is activation of intracellular protein kinases in response to the binding of membrane-impermeable peptide hormones to the external cell surface.[1]
cGMP is a common regulator of ion channel conductance, glycogenolysis, and cellular apoptosis. It also relaxes smooth muscle tissues. In blood vessels, relaxation of vascular smooth muscles lead to vasodilation and increased blood flow.
INDICATIONS
Treatment of erectile dysfunction (ED).
ADULT DOSAGE
Adults: Initial: 10mg 1 hr prior to sexual activity. Titrate: May decrease to 5mg or increase to max of 20mg based on response. Max: 1 tab/day. Elderly: ≥65 yrs: Initial: 5mg. Moderate Hepatic Impairment (Child-Pugh B): Initial: 5mg. Max: 10mg. Concomitant Ritonavir: Max: 2.5mg/72 hrs. Concomitant Indinavir/Saquinavir/Atazanavir/Clarithromycin/Ketoconazole 400mg daily/Itraconazole 400mg daily: Max: 2.5mg/24 hrs. Concomitant Ketoconazole 200mg daily/Itraconazole 200mg daily/Erythromycin: Max: 5mg/24 hrs. Concomitant Stable α-blocker: Initial: 5mg; 2.5mg when used with certain CYP3A4 inhibitors.
HOW SUPPLIED
Tab: 2.5mg, 5mg, 10mg, 20mg
CONTRAINDICATIONS
Concomitant nitrates or nitric oxide donors.
WARNINGS/PRECAUTIONS
Avoid when sexual activity is inadvisable due to underlying cardiovascular (CV) status. Increased sensitivity to vasodilation effects with left ventricular outflow obstruction. Decrease in supine BP reported. Avoid with unstable angina, hypotension (resting SBP<90 mmHg), uncontrolled HTN (>170/110 mmHg), recent history of stroke, life-threatening arrhythmia, myocardial infarction (MI) within last 6 months, severe cardiac failure, severe hepatic impairment (Child-Pugh C), end-stage renal disease (ESRD) requiring dialysis, hereditary degenerative retinal disorders including retinitis pigmentosa, congenital QT prolongation. Rare reports of prolonged erections >4 hrs and priapism. Caution with bleeding disorders, peptic ulcers, anatomical deformation of the penis or predisposition to priapism. Rare reports of non-arteritic anterior ischemic optic neuropathy (NAION) with phosphodiesterase type 5 (PDE5) inhibitors. Sudden decrease or loss of hearing accompanied by tinnitus and dizziness reported.
ADVERSE REACTIONS
Headache, flushing, rhinitis, dyspepsia, sinusitis, flu syndrome, dizziness, nausea.
DRUG INTERACTIONS
See Contraindications. Avoid use with Class IA (eg, quinidine, procainamide) or Class III (eg, amiodarone, sotalol) antiarrhythmics and other agents for ED. Caution with medications known to prolong QT interval. Increased levels with CYP3A4 inhibitors (eg, ritonavir, indinavir, saquinavir, atazanavir, ketoconazole, itraconazole, clarithromycin, erythromycin). Additive hypotensive effect, which may lead to symptomatic hypotension when used with α-blockers. Reduced clearance with CYP3A4/5 and CYP2C9 inhibitors.
PREGNANCY
Category B, not for use in nursing.
MECHANISM OF ACTION
PDE5 inhibitor; increases the amount of cGMP, which causes smooth muscle relaxation, allowing increased blood flow into the penis, resulting in erection.
PHARMACOKINETICS
Absorption: Rapid, absolute bioavailability (15%); Tmax=30 min-2 hrs. Distribution: Vd=208L; plasma protein binding (95%). Metabolism: Via CYP3A4, CYP3A5, CYP2C. M1 (major metabolite). Elimination: Feces (91-95%), urine (2-6%); T1/2=4-5 hrs.
ASSESSMENT
Assess for CV disease, left ventricular outflow obstruction (eg, aortic stenosis, idiopathic hypertrophic subaortic stenosis), congenital QT prolongation, retinitis pigmentosa, bleeding disorders, active peptic ulceration, anatomical deformation of the penis or conditions that predispose to priapism (eg, sickle cell anemia, multiple myleoma, leukemia), and renal/hepatic impairment. Assess potential underlying causes of ED and for possible drug interactions.
MONITORING
Monitor potential for cardiac risk due to sexual activity, hypotension, color vision changes or other eye adverse events (eg, NAION), hypersensitivity reactions, and hearing impairment. Monitor for adverse events when used in combination with other drugs.
PATIENT COUNSELING
Discuss risks and benefits of therapy. Seek medical assistance if erection persists >4 hrs. Inform that postural hypotension may occur. Advise of potential BP-lowering effect of nitrates, α-blockers and antihypertensive medications, and cardiac risk of sexual activity. Counsel about protective measures necessary to guard against STDs, including HIV; drug does not protect against STDs. D/C and inform doctor if sudden loss of vision or hearing occur. Counsel to take as prescribed.
ADMINISTRATION/STORAGE
Administration: Oral route. Storage: 25°C (77°F); excursions permitted to 15-30°C (59-86°F).
WebMD:
What Are the Differences Between Cialis, Levitra, Staxyn, Stendra, and Viagra?
Cialis, Levitra, Staxyn, Stendra, and Viagra work by a similar mechanism to cause erections. There are subtle differences in how long the drug works and how quickly it works. Levitra works a little longer than Viagra. They both take effect in about 30 minutes. With Levitra, the effects last for about 5 hours. With Viagra, the effects last approximately 4 hours.
Cialis works a bit faster (within about 15 minutes), and the effects last much longer -- up to 36 hours in some cases. Stendra can start working in as little as 15 minutes and last up to 6 hours. Staxyn is an orally disintegrating tablet that contains the same active ingredient as Levitra but is not interchangeable with Levitra tablets.
If One of These Drugs Isn't Effective for Erectile Dysfunction, Can I Try Another?
Yes, but because these drugs work the same way, it's unlikely that you'll have success with one if you've failed to achieve an adequate erection with another.
What Precautions Should I Take Before Taking One of These Drugs?
There are certain situations in which these drugs may not be safe to take. Before taking them, tell your doctor:
If you are allergic to any drugs, including Viagra or other ED medications.
About any prescription or nonprescription medications you are currently taking, including herbal and dietary supplements.
If you are scheduled for surgery, including dental surgery.
If you take nitroglycerin or a long-acting nitrate to treat chest pain. The combination of Cialis, Levitra, Staxyn, Stendra, or Viagra with these drugs can cause dangerously low blood pressure.
If you take alpha-blockers for blood pressure or prostate problems. The combination of Cialis, Levitra, Staxyn, Stendra, or Viagra with these drugs can also cause dangerously low blood pressure. Patients should not be started on Staxyn unless they have previously taken Levitra as directed by their doctor.
In addition, always follow the directions on your prescription label carefully and ask your doctor or pharmacist to explain any part that you do not understand. Take these drugs exactly as directed. Do not take more or less or take it more often than prescribed by your doctor. Do not take these drugs more than once a day.
Who Should Not Take Cialis, Levitra, Staxyn, Stendra, or Viagra?
If you have suffered from a heart attack, stroke or life threatening arrhythmia (irregular heart rate) within the last 6 months you should discuss other options with your doctor. It is also advised to avoid these drugs if you have uncontrolled high or low blood pressure or if you experience chest pain with sex.
What Are the Side Effects of Cialis, Levitra, Staxyn, Stendra, and Viagra?
Side effects are not common but they can occur. Side effects can include:
Headache
Upset stomach or heartburn
Flushing (feeling warm)
Nasal congestion
Changes in vision (color, glare)
Back pain (with Cialis)
Call your doctor if you experience severe forms of these symptoms or if they do not go away after 4-8 hours.
Warning
Call your doctor or seek emergency treatment immediately if you experience any of the following symptoms:
Rash
Painful erection
Prolonged erection (longer than 4 hours)
Fainting
Chest pain
Itching or burning during urination
Stop taking these medications and call a doctor or health care provider right away if you experience sudden or decreased vision loss in one or both eyes. A rare vision problem called NAION has been reported by a few men using these drugs. NAION (nonarteritic anterior ischemic optic neuropathy) causes a sudden loss of eyesight because blood flow is blocked to the optic nerve. People who have a higher chance for NAION include those who:
Are over 50 years old
Smoke
Have heart disease
Have diabetes
Have high blood pressure
Have high cholesterol
Have certain eye problems
How Should These Drugs Be Stored?
These drugs should be kept in its original container and out of reach of children. Store them away from excess heat and moisture (not in the bathroom). Discard any medication that has expired or is no longer needed.
Further Reading:
PDR: http://www.pdr.net/drug-summary/levitra?...75&id=2112
Levitra
(vardenafil hcl) - Merck
THERAPEUTIC CLASS
Phosphodiesterase type 5 inhibitor http://en.wikipedia.org/wiki/PDE5_inhibitor
A phosphodiesterase type 5 inhibitor, often shortened to PDE5 inhibitor, is a drug used to block the degradative action of phosphodiesterase type 5 on cyclic GMP in the smooth muscle cells lining the blood vessels supplying the corpus cavernosum of the penis. These drugs are used in the treatment of erectile dysfunction, and were the first effective oral treatment available for the condition. Because PDE5 is also present in the arterial wall smooth muscle within the lungs, PDE5 inhibitors have also been explored for the treatment of pulmonary hypertension, a disease in which blood vessels in the lungs become overloaded with fluid, usually as a result of failure of the left ventricle of the heart.
Mechanism of action
Part of the physiological process of erection involves the release of nitric oxide (NO) in vasculature of the corpus cavernosum as a result of sexual stimulation. NO activates the enzyme guanylate cyclase which results in increased levels of cyclic guanosine monophosphate (cGMP), leading to smooth muscle relaxation in blood vessels supplying the corpus cavernosum, resulting in increased blood flow and an erection.
PDE5 inhibitors inhibit the degradation of cGMP by phosphodiesterase type 5 (PDE5), increasing bloodflow to the penis during sexual stimulation.
This mode of action means that PDE5 inhibitors are ineffective without sexual stimulation.
Cyclic guanosine monophosphate (cGMP) is a cyclic nucleotide derived from guanosine triphosphate (GTP). cGMP acts as a second messenger much like cyclic AMP. Its most likely mechanism of action is activation of intracellular protein kinases in response to the binding of membrane-impermeable peptide hormones to the external cell surface.[1]
cGMP is a common regulator of ion channel conductance, glycogenolysis, and cellular apoptosis. It also relaxes smooth muscle tissues. In blood vessels, relaxation of vascular smooth muscles lead to vasodilation and increased blood flow.
INDICATIONS
Treatment of erectile dysfunction (ED).
ADULT DOSAGE
Adults: Initial: 10mg 1 hr prior to sexual activity. Titrate: May decrease to 5mg or increase to max of 20mg based on response. Max: 1 tab/day. Elderly: ≥65 yrs: Initial: 5mg. Moderate Hepatic Impairment (Child-Pugh B): Initial: 5mg. Max: 10mg. Concomitant Ritonavir: Max: 2.5mg/72 hrs. Concomitant Indinavir/Saquinavir/Atazanavir/Clarithromycin/Ketoconazole 400mg daily/Itraconazole 400mg daily: Max: 2.5mg/24 hrs. Concomitant Ketoconazole 200mg daily/Itraconazole 200mg daily/Erythromycin: Max: 5mg/24 hrs. Concomitant Stable α-blocker: Initial: 5mg; 2.5mg when used with certain CYP3A4 inhibitors.
HOW SUPPLIED
Tab: 2.5mg, 5mg, 10mg, 20mg
CONTRAINDICATIONS
Concomitant nitrates or nitric oxide donors.
WARNINGS/PRECAUTIONS
Avoid when sexual activity is inadvisable due to underlying cardiovascular (CV) status. Increased sensitivity to vasodilation effects with left ventricular outflow obstruction. Decrease in supine BP reported. Avoid with unstable angina, hypotension (resting SBP<90 mmHg), uncontrolled HTN (>170/110 mmHg), recent history of stroke, life-threatening arrhythmia, myocardial infarction (MI) within last 6 months, severe cardiac failure, severe hepatic impairment (Child-Pugh C), end-stage renal disease (ESRD) requiring dialysis, hereditary degenerative retinal disorders including retinitis pigmentosa, congenital QT prolongation. Rare reports of prolonged erections >4 hrs and priapism. Caution with bleeding disorders, peptic ulcers, anatomical deformation of the penis or predisposition to priapism. Rare reports of non-arteritic anterior ischemic optic neuropathy (NAION) with phosphodiesterase type 5 (PDE5) inhibitors. Sudden decrease or loss of hearing accompanied by tinnitus and dizziness reported.
ADVERSE REACTIONS
Headache, flushing, rhinitis, dyspepsia, sinusitis, flu syndrome, dizziness, nausea.
DRUG INTERACTIONS
See Contraindications. Avoid use with Class IA (eg, quinidine, procainamide) or Class III (eg, amiodarone, sotalol) antiarrhythmics and other agents for ED. Caution with medications known to prolong QT interval. Increased levels with CYP3A4 inhibitors (eg, ritonavir, indinavir, saquinavir, atazanavir, ketoconazole, itraconazole, clarithromycin, erythromycin). Additive hypotensive effect, which may lead to symptomatic hypotension when used with α-blockers. Reduced clearance with CYP3A4/5 and CYP2C9 inhibitors.
PREGNANCY
Category B, not for use in nursing.
MECHANISM OF ACTION
PDE5 inhibitor; increases the amount of cGMP, which causes smooth muscle relaxation, allowing increased blood flow into the penis, resulting in erection.
PHARMACOKINETICS
Absorption: Rapid, absolute bioavailability (15%); Tmax=30 min-2 hrs. Distribution: Vd=208L; plasma protein binding (95%). Metabolism: Via CYP3A4, CYP3A5, CYP2C. M1 (major metabolite). Elimination: Feces (91-95%), urine (2-6%); T1/2=4-5 hrs.
ASSESSMENT
Assess for CV disease, left ventricular outflow obstruction (eg, aortic stenosis, idiopathic hypertrophic subaortic stenosis), congenital QT prolongation, retinitis pigmentosa, bleeding disorders, active peptic ulceration, anatomical deformation of the penis or conditions that predispose to priapism (eg, sickle cell anemia, multiple myleoma, leukemia), and renal/hepatic impairment. Assess potential underlying causes of ED and for possible drug interactions.
MONITORING
Monitor potential for cardiac risk due to sexual activity, hypotension, color vision changes or other eye adverse events (eg, NAION), hypersensitivity reactions, and hearing impairment. Monitor for adverse events when used in combination with other drugs.
PATIENT COUNSELING
Discuss risks and benefits of therapy. Seek medical assistance if erection persists >4 hrs. Inform that postural hypotension may occur. Advise of potential BP-lowering effect of nitrates, α-blockers and antihypertensive medications, and cardiac risk of sexual activity. Counsel about protective measures necessary to guard against STDs, including HIV; drug does not protect against STDs. D/C and inform doctor if sudden loss of vision or hearing occur. Counsel to take as prescribed.
ADMINISTRATION/STORAGE
Administration: Oral route. Storage: 25°C (77°F); excursions permitted to 15-30°C (59-86°F).