ADVERSE REACTIONS

In addition, the combination of heparin and VIAGRA had an additive effect on bleeding time in the anesthetized rabbit, but this interaction has not been studied in humans.

4. Contraindications

Therefore, the use of such combinations is not recommended. There have been postmarketing reports of bleeding events in patients who have taken VIAGRA. A causal relationship between VIAGRA and these events has not been established. In humans, VIAGRA has no effect on bleeding time when taken alone or with aspirin. However, in vitro studies with human platelets indicate that sildenafil potentiates the antiaggregatory effect of sodium nitroprusside (a nitric oxide donor). The safety of VIAGRA is unknown in patients with bleeding disorders and patients with active peptic ulceration.

The use of VIAGRA offers no protection against sexually transmitted diseases.

3. Dosage Forms and Strengths

In some patients, concomitant use of these two drug classes can lower blood pressure significantly [see Drug Interactions (7.2) and Clinical Pharmacology (12.2)] leading to symptomatic hypotension (e.g., dizziness, lightheadedness, fainting). Consideration should be given to the following: Patients who demonstrate hemodynamic instability on alpha-blocker therapy alone are at increased risk of symptomatic hypotension with concomitant use of PDE5 inhibitors. Patients should be stable on alpha-blocker therapy prior to initiating a PDE5 inhibitor. In those patients who are stable on alpha-blocker therapy, PDE5 inhibitors should be initiated at the lowest dose [see Dosage and Administration (2.3)]. In those patients already taking an optimized dose of a PDE5 inhibitor, alpha-blocker therapy should be initiated at the lowest dose.

8.1 Pregnancy: Teratogenic effects

Stepwise increase in alpha-blocker dose may be associated with further lowering of blood pressure when taking a PDE5 inhibitor. Safety of combined use of PDE5 inhibitors and alpha-blockers may be affected by other variables, including intravascular volume depletion and other anti-hypertensive drugs. VIAGRA has systemic vasodilatory sildenafil tablets lp 100 mg properties and may further lower blood pressure in patients taking anti-hypertensive medications. In a separate drug interaction study, when amlodipine, 5 mg or 10 mg, and VIAGRA, 100 mg were orally administered concomitantly to hypertensive patients mean additional blood pressure reduction of 8 mmHg systolic and 7 mmHg diastolic were noted [see Drug Interactions (7.3) and Clinical Pharmacology (12.2)]. If VIAGRA is prescribed to patients taking ritonavir, caution should be used.

How should I store sildenafil?

Data from subjects exposed to high systemic levels of sildenafil are limited. Decreased blood pressure, syncope, and prolonged erection were reported in some healthy volunteers exposed to high doses of sildenafil (200–800 mg). To decrease the chance of adverse reactions in patients taking ritonavir, a decrease in sildenafil dosage is recommended [see Dosage and Administration (2.4), Drug Interactions (7.4), and Clinical Pharmacology (12.3)]. The safety and efficacy of combinations of VIAGRA with other PDE5 Inhibitors, including REVATIO or other pulmonary arterial hypertension (PAH) treatments containing sildenafil, or other treatments for erectile dysfunction have not been studied. Such combinations may further lower blood pressure. Counseling of patients about the protective measures necessary to guard against sexually transmitted diseases, including the Human Immunodeficiency Virus (HIV), may be considered. The following are discussed in more detail in other sections of the labeling: Cardiovascular [see Warnings and Precautions (5.1)] Prolonged Erection and Priapism [see Warnings and Precautions (5.2)] Effects on the Eye

• 20mg sildenafil provides a balance between effectiveness and safety.
• It is not a cure for ED but helps achieve and maintain an erection.
• Using sildenafil without medical advice can be risky.
• The medication may cause nasal congestion or stomach upset.
• Always follow the dosage instructions provided by your healthcare provider.

[see Warnings and Precautions (5.3)] Hearing Loss [see Warnings and Precautions (5.4)] Hypotension when Co-administered with Alpha-blockers or Anti-hypertensives [see Warnings and Precautions (5.5)] Adverse Reactions with the Concomitant Use of Ritonavir

[see Warnings and Precautions (5.6)] Combination with other PDE5 Inhibitors or Other Erectile Dysfunction Therapies [see Warnings and Precautions (5.7)] Effects on Bleeding [see Warnings and Precautions (5.8)] Counseling Patients About Sexually

• Sildenafil is available in various dosage forms beyond oral tablets.
• Revatio is available as an injectable solution for intravenous use in PAH.
• The IV dose is 10mg administered three times a day as a bolus injection.
• There is also an oral suspension formulation of Revatio for pediatric use.
• A topical gel formulation of sildenafil has been investigated for ED.
• Orally disintegrating tablets and fast-dissolving films are also in development.
• Different formulations aim to improve onset of action or patient convenience.
• The bioavailability and pharmacokinetics differ between formulations.
• Only the oral tablet and IV solution are currently widely approved and available.
• Patients should never switch formulations without consulting their doctor.
• The dose and dosing frequency are specific to each formulation and indication.

Transmitted Diseases [see Warnings and Precautions (5.9)] The most common adverse reactions reported in clinical trials (≥ 2%) are headache, flushing, dyspepsia, abnormal vision, nasal congestion, back pain, myalgia, nausea, dizziness, and rash.

• Sildenafil interacts with nitrate medications, causing dangerous drops in blood pressure.
• Store sildenafil in a cool, dry place away from children.
• 20mg is often recommended as a starting dose for ED treatment.
• Food, especially high-fat meals, can delay its onset of action.
• Regular use can improve erectile response over time if prescribed.

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot

Liver Dose Adjustments

Therefore, treatments for erectile dysfunction, including VIAGRA, should not be generally used in men for whom sexual activity is inadvisable because of their underlying cardiovascular status. The evaluation of erectile dysfunction should include a determination of potential underlying causes and the identification of appropriate treatment following a complete medical assessment. VIAGRA has systemic vasodilatory properties that resulted in transient decreases in supine blood pressure in healthy volunteers (mean maximum decrease of 8.4/5.5 mmHg), [see Clinical Pharmacology (12.2)]. While this normally would be expected to be of little consequence in most patients, prior to prescribing VIAGRA, physicians should carefully consider whether their patients with underlying cardiovascular disease could be affected adversely by such vasodilatory effects, especially in combination with sexual activity. Use with caution in patients with the following underlying conditions which can be particularly sensitive to the actions of vasodilators including VIAGRA – those with left ventricular outflow obstruction (e.g., aortic stenosis, idiopathic hypertrophic subaortic stenosis) and those with severely impaired autonomic control of blood pressure.

Viagra Tablets

There are no controlled clinical data on the safety or efficacy of VIAGRA in the following groups; if prescribed, this should be done with caution. Patients who have suffered a myocardial infarction, stroke, or life-threatening arrhythmia within the last 6 months; Patients with resting hypotension (BP <90/50 mmHg) or hypertension (BP >170/110 mmHg); Patients with cardiac failure or coronary artery disease causing unstable angina. Prolonged erection greater than 4 hours and priapism (painful erections greater than 6 hours in duration) have been reported infrequently since market approval of VIAGRA. If priapism is not treated immediately, penile tissue damage and permanent loss of potency could result. VIAGRA should be used with caution in patients with anatomical deformation of the penis (such as angulation, cavernosal fibrosis or Peyronie's disease), or in patients who have conditions which may predispose them to priapism (such as sickle cell anemia, multiple myeloma, or leukemia).

Revatio Tablets

However, there are no controlled clinical data on the safety or efficacy of VIAGRA in patients with sickle cell or related anemias. Physicians should advise patients to stop use of all phosphodiesterase type 5 (PDE5) inhibitors, including VIAGRA, and seek medical attention in the event of a sudden loss of vision in one or both eyes. Such an event may be a sign of non-arteritic anterior ischemic optic neuropathy (NAION), a rare condition and a cause of decreased vision including permanent loss of vision, that has been reported rarely post-marketing in temporal association with the use of all PDE5 inhibitors. Based on published literature, the annual incidence of NAION is 2.5–11.8 cases per 100,000 in males aged ≥ 50. An observational case-crossover study evaluated the risk of NAION when PDE5 inhibitor use, as a class, occurred immediately before NAION onset (within 5 half-lives), compared to PDE5 inhibitor use in a prior time period. be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

What other information should I know?

The results suggest an approximate 2-fold increase in the risk of NAION, with a risk estimate of 2.15 (95% CI 1.06, 4.34). A similar study reported a consistent result, with a risk estimate of 2.27 (95% CI 0.99, 5.20). Other risk factors for NAION, such as the presence of "crowded" optic disc, may have contributed to the occurrence of NAION in these studies. Neither the rare post-marketing reports, nor the association of PDE5 inhibitor use and NAION in the observational studies, substantiate a causal relationship between PDE5 inhibitor use and NAION [see Adverse Reactions (6.2)]. Physicians should consider whether their patients with underlying NAION risk factors could be adversely affected by use of PDE5 inhibitors.

How Sildenafil Works to Treat ED

Individuals who have already experienced NAION are at increased risk of NAION recurrence. Therefore, PDE5 inhibitors, including VIAGRA, should be used with caution in these patients and only when the anticipated benefits sildenafil citrate tables outweigh the risks. Individuals with "crowded" optic disc are also considered at greater risk for NAION compared to the general population, however, evidence is insufficient to support screening of prospective users of PDE5 inhibitors, including VIAGRA, for this uncommon condition. There are no controlled clinical data on the safety or efficacy of VIAGRA in patients with retinitis pigmentosa (a minority of these patients have genetic disorders of retinal phosphodiesterases); if prescribed, this should be done with caution. Physicians should advise patients to stop taking PDE5 inhibitors, including VIAGRA, and seek prompt medical attention in the event of sudden decrease or loss of hearing.

8.6 Renal Impairment

These events, which may be accompanied by tinnitus and dizziness, have been reported in temporal association to the intake of PDE5 inhibitors, including VIAGRA. It is not possible to determine whether these events are related directly to the use of PDE5 inhibitors or to other factors [see Adverse Reactions (6.1, 6.2)]. Caution is advised when PDE5 inhibitors are co-administered with alpha-blockers. PDE5 inhibitors, including VIAGRA, and alpha-adrenergic blocking agents are both vasodilators with blood pressure lowering effects. When vasodilators are used in combination, an additive effect on blood pressure may occur.