Viagra Information
Viagra (Sildenafil citrate) Description
Viagra (Sildenafil citrate) , an oral therapy for erectile dysfunction, is the citrate salt of sildenafil, a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5).
Sildenafil citrate is designated chemically as 1-[[3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1-pyrazolo[4,3-]pyrimidin-5-yl)-4-ethoxyphenyl]sulfonyl]-4-methylpiperazine citrate and has the following structural formula:
Sildenafil citrate is a white to off-white crystalline powder with a solubility of 3.5 mg/mL in water and a molecular weight of 666.7. Viagra (Sildenafil citrate) is formulated as blue, film-coated rounded-diamond-shaped tablets equivalent to 25 mg, 50 mg and 100 mg of sildenafil for oral administration. In addition to the active ingredient, sildenafil citrate, each tablet contains the following inactive ingredients: microcrystalline cellulose, anhydrous dibasic calcium phosphate, croscarmellose sodium, magnesium stearate, hypromellose, titanium dioxide, lactose, triacetin, and FD & C Blue #2 aluminum lake.
Viagra (Sildenafil citrate) Clinical Pharmacology
The physiologic mechanism of erection of the penis involves release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. NO then activates the enzyme guanylate cyclase, which results in increased levels of cyclic guanosine monophosphate (cGMP), producing smooth muscle relaxation in the corpus cavernosum and allowing inflow of blood. Sildenafil has no direct relaxant effect on isolated human corpus cavernosum, but enhances the effect of nitric oxide (NO) by inhibiting phosphodiesterase type 5 (PDE5), which is responsible for degradation of cGMP in the corpus cavernosum. When sexual stimulation causes local release of NO, inhibition of PDE5 by sildenafil causes increased levels of cGMP in the corpus cavernosum, resulting in smooth muscle relaxation and inflow of blood to the corpus cavernosum. Sildenafil at recommended doses has no effect in the absence of sexual stimulation.
Studies have shown that sildenafil is selective for PDE5. Its effect is more potent on PDE5 than on other known phosphodiesterases (10-fold for PDE6, >80-fold for PDE1, >700-fold for PDE2, PDE3, PDE4, PDE7, PDE8, PDE9, PDE10, and PDE11). The approximately 4,000-fold selectivity for PDE5 versus PDE3 is important because PDE3 is involved in control of cardiac contractility. Sildenafil is only about 10-fold as potent for PDE5 compared to PDE6, an enzyme found in the retina which is involved in the phototransduction pathway of the retina. This lower selectivity is thought to be the basis for abnormalities related to color vision observed with higher doses or plasma levels (see ).
In addition to human corpus cavernosum smooth muscle, PDE5 is also found in lower concentrations in other tissues including platelets, vascular and visceral smooth muscle, and skeletal muscle. The inhibition of PDE5 in these tissues by sildenafil may be the basis for the enhanced platelet antiaggregatory activity of nitric oxide observed , an inhibition of platelet thrombus formation and peripheral arterial-venous dilatation .
Viagra (Sildenafil citrate) is rapidly absorbed after oral administration, with a mean absolute bioavailability of 41% (range 25–63%). Its pharmacokinetics are dose-proportional over the recommended dose range. It is eliminated predominantly by hepatic metabolism (mainly cytochrome P450 3A4) and is converted to an active metabolite with properties similar to the parent, sildenafil. The concomitant use of potent cytochrome P450 3A4 inhibitors (e.g., erythromycin, ketoconazole, itraconazole) as well as the nonspecific CYP inhibitor, cimetidine, is associated with increased plasma levels of sildenafil (see ). Both sildenafil and the metabolite have terminal half lives of about 4 hours.
Mean sildenafil plasma concentrations measured after the administration of a single oral dose of 100 mg to healthy male volunteers is depicted below:
In clinical studies, Viagra (Sildenafil citrate) was assessed for its effect on the ability of men with erectile dysfunction (ED) to engage in sexual activity and in many cases specifically on the ability to achieve and maintain an erection sufficient for satisfactory sexual activity. Viagra (Sildenafil citrate) was evaluated primarily at doses of 25 mg, 50 mg and 100 mg in 21 randomized, double-blind, placebo-controlled trials of up to 6 months in duration, using a variety of study designs (fixed dose, titration, parallel, crossover). Viagra (Sildenafil citrate) was administered to more than 3,000 patients aged 19 to 87 years, with ED of various etiologies (organic, psychogenic, mixed) with a mean duration of 5 years. Viagra (Sildenafil citrate) demonstrated statistically significant improvement compared to placebo in all 21 studies. The studies that established benefit demonstrated improvements in success rates for sexual intercourse compared with placebo.
The effectiveness of Viagra (Sildenafil citrate) was evaluated in most studies using several assessment instruments. The primary measure in the principal studies was a sexual function questionnaire (the International Index of Erectile Function - IIEF) administered during a 4-week treatment-free run-in period, at baseline, at follow-up visits, and at the end of double-blind, placebo-controlled, at-home treatment. Two of the questions from the IIEF served as primary study endpoints; categorical responses were elicited to questions about (1) the ability to achieve erections sufficient for sexual intercourse and (2) the maintenance of erections after penetration. The patient addressed both questions at the final visit for the last 4 weeks of the study. The possible categorical responses to these questions were (0) no attempted intercourse, (1) never or almost never, (2) a few times, (3) sometimes, (4) most times, and (5) almost always or always. Also collected as part of the IIEF was information about other aspects of sexual function, including information on erectile function, orgasm, desire, satisfaction with intercourse, and overall sexual satisfaction. Sexual function data were also recorded by patients in a daily diary. In addition, patients were asked a global efficacy question and an optional partner questionnaire was administered.
The effect on one of the major end points, maintenance of erections after penetration, is shown in Figure 3, for the pooled results of 5 fixed-dose, dose-response studies of greater than one month duration, showing response according to baseline function. Results with all doses have been pooled, but scores showed greater improvement at the 50 and 100 mg doses than at 25 mg. The pattern of responses was similar for the other principal question, the ability to achieve an erection sufficient for intercourse. The titration studies, in which most patients received 100 mg, showed similar results. Figure 3 shows that regardless of the baseline levels of function, subsequent function in patients treated with Viagra (Sildenafil citrate) was better than that seen in patients treated with placebo. At the same time, on-treatment function was better in treated patients who were less impaired at baseline.
The frequency of patients reporting improvement of erections in response to a global question in four of the randomized, double-blind, parallel, placebo-controlled fixed dose studies (1797 patients) of 12 to 24 weeks duration is shown in Figure 4. These patients had erectile dysfunction at baseline that was characterized by median categorical scores of 2 (a few times) on principal IIEF questions. Erectile dysfunction was attributed to organic (58%; generally not characterized, but including diabetes and excluding spinal cord injury), psychogenic (17%), or mixed (24%) etiologies. Sixty-three percent, 74%, and 82% of the patients on 25 mg, 50 mg and 100 mg of Viagra (Sildenafil citrate) , respectively, reported an improvement in their erections, compared to 24% on placebo. In the titration studies (n=644) (with most patients eventually receiving 100 mg), results were similar.
The patients in studies had varying degrees of ED. One-third to one-half of the subjects in these studies reported successful intercourse at least once during a 4-week, treatment-free run-in period.
In many of the studies, of both fixed dose and titration designs, daily diaries were kept by patients. In these studies, involving about 1600 patients, analyses of patient diaries showed no effect of Viagra (Sildenafil citrate) on rates of attempted intercourse (about 2 per week), but there was clear treatment-related improvement in sexual function: per patient weekly success rates averaged 1.3 on 50–100 mg of Viagra (Sildenafil citrate) vs 0.4 on placebo; similarly, group mean success rates (total successes divided by total attempts) were about 66% on Viagra (Sildenafil citrate) vs about 20% on placebo.
During 3 to 6 months of double-blind treatment or longer-term (1 year), open-label studies, few patients withdrew from active treatment for any reason, including lack of effectiveness. At the end of the long-term study, 88% of patients reported that Viagra (Sildenafil citrate) improved their erections.
Men with untreated ED had relatively low baseline scores for all aspects of sexual function measured (again using a 5-point scale) in the IIEF. Viagra (Sildenafil citrate) improved these aspects of sexual function: frequency, firmness and maintenance of erections; frequency of orgasm; frequency and level of desire; frequency, satisfaction and enjoyment of intercourse; and overall relationship satisfaction.
One randomized, double-blind, flexible-dose, placebo-controlled study included only patients with erectile dysfunction attributed to complications of diabetes mellitus (n=268). As in the other titration studies, patients were started on 50 mg and allowed to adjust the dose up to 100 mg or down to 25 mg of Viagra (Sildenafil citrate) ; all patients, however, were receiving 50 mg or 100 mg at the end of the study. There were highly statistically significant improvements on the two principal IIEF questions (frequency of successful penetration during sexual activity and maintenance of erections after penetration) on Viagra (Sildenafil citrate) compared to placebo. On a global improvement question, 57% of Viagra (Sildenafil citrate) patients reported improved erections versus 10% on placebo. Diary data indicated that on Viagra (Sildenafil citrate) , 48% of intercourse attempts were successful versus 12% on placebo.
One randomized, double-blind, placebo-controlled, crossover, flexible-dose (up to 100 mg) study of patients with erectile dysfunction resulting from spinal cord injury (n=178) was conducted. The changes from baseline in scoring on the two end point questions (frequency of successful penetration during sexual activity and maintenance of erections after penetration) were highly statistically significantly in favor of Viagra (Sildenafil citrate) . On a global improvement question, 83% of patients reported improved erections on Viagra (Sildenafil citrate) versus 12% on placebo. Diary data indicated that on Viagra (Sildenafil citrate) , 59% of attempts at sexual intercourse were successful compared to 13% on placebo.
Across all trials, Viagra (Sildenafil citrate) improved the erections of 43% of radical prostatectomy patients compared to 15% on placebo.
Subgroup analyses of responses to a global improvement question in patients with psychogenic etiology in two fixed-dose studies (total n=179) and two titration studies (total n=149) showed 84% of Viagra (Sildenafil citrate) patients reported improvement in erections compared with 26% of placebo. The changes from baseline in scoring on the two end point questions (frequency of successful penetration during sexual activity and maintenance of erections after penetration) were highly statistically significantly in favor of Viagra (Sildenafil citrate) Diary data in two of the studies (n=178) showed rates of successful intercourse per attempt of 70% for Viagra (Sildenafil citrate) and 29% for placebo.
A review of population subgroups demonstrated efficacy regardless of baseline severity, etiology, race and age. Viagra (Sildenafil citrate) was effective in a broad range of ED patients, including those with a history of coronary artery disease, hypertension, other cardiac disease, peripheral vascular disease, diabetes mellitus, depression, coronary artery bypass graft (CABG), radical prostatectomy, transurethral resection of the prostate (TURP) and spinal cord injury, and in patients taking antidepressants/antipsychotics and antihypertensives/diuretics.
Analysis of the safety database showed no apparent difference in the side effect profile in patients taking Viagra (Sildenafil citrate) with and without antihypertensive medication. This analysis was performed retrospectively, and was not powered to detect any pre-specified difference in adverse reactions.
Viagra (Sildenafil citrate) Indication And Usage
Viagra (Sildenafil citrate) is indicated for the treatment of erectile dysfunction.
Viagra (Sildenafil citrate) Contraindications
Consistent with its known effects on the nitric oxide/cGMP pathway (see ), Viagra (Sildenafil citrate) was shown to potentiate the hypotensive effects of nitrates, and its administration to patients who are using organic nitrates, either regularly and/or intermittently, in any form is therefore contraindicated.
After patients have taken Viagra (Sildenafil citrate) , it is unknown when nitrates, if necessary, can be safely administered. Based on the pharmacokinetic profile of a single 100 mg oral dose given to healthy normal volunteers, the plasma levels of sildenafil at 24 hours post dose are approximately 2 ng/mL (compared to peak plasma levels of approximately 440 ng/mL) (see ). In the following patients: age >65, hepatic impairment (e.g., cirrhosis), severe renal impairment (e.g., creatinine clearance <30 mL/min), and concomitant use of potent cytochrome P450 3A4 inhibitors (erythromycin), plasma levels of sildenafil at 24 hours post dose have been found to be 3 to 8 times higher than those seen in healthy volunteers. Although plasma levels of sildenafil at 24 hours post dose are much lower than at peak concentration, it is unknown whether nitrates can be safely coadministered at this time point.
Viagra (Sildenafil citrate) is contraindicated in patients with a known hypersensitivity to any component of the tablet.
Viagra (Sildenafil citrate) Warnings
There is a potential for cardiac risk of sexual activity in patients with preexisting cardiovascular disease. Therefore, treatments for erectile dysfunction, including Viagra (Sildenafil citrate) , should not be generally used in men for whom sexual activity is inadvisable because of their underlying cardiovascular status.
Viagra (Sildenafil citrate) 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 ). While this normally would be expected to be of little consequence in most patients, prior to prescribing Viagra (Sildenafil citrate) , 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.
Patients with the following underlying conditions can be particularly sensitive to the actions of vasodilators including Viagra (Sildenafil citrate) – those with left ventricular outflow obstruction (e.g. aortic stenosis, idiopathic hypertrophic subaortic stenosis) and those with severely impaired autonomic control of blood pressure.
There is no controlled clinical data on the safety or efficacy of Viagra (Sildenafil citrate) in the following groups; if prescribed, this should be done with caution.
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 (Sildenafil citrate) . In the event of an erection that persists longer than 4 hours, the patient should seek immediate medical assistance. If priapism is not treated immediately, penile tissue damage and permanent loss of potency could result.
The concomitant administration of the protease inhibitor ritonavir substantially increases serum concentrations of sildenafil (). If Viagra (Sildenafil citrate) is prescribed to patients taking ritonavir, caution should be used. Data from subjects exposed to high systemic levels of sildenafil are limited. Visual disturbances occurred more commonly at higher levels of sildenafil exposure. 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 events in patients taking ritonavir, a decrease in sildenafil dosage is recommended (see and ).
Viagra (Sildenafil citrate) Precautions
The evaluation of erectile dysfunction should include a determination of potential underlying causes and the identification of appropriate treatment following a complete medical assessment.
Before prescribing Viagra (Sildenafil citrate) , it is important to note the following:
Caution is advised when Phosphodiesterase Type 5 (PDE5) inhibitors are co-administered with alpha-blockers. PDE5 inhibitors, including Viagra (Sildenafil citrate) , 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 be anticipated. In some patients, concomitant use of these two drug classes can lower blood pressure significantly (see ) leading to symptomatic hypotension (e.g. dizziness, lightheadedness, fainting).
Consideration should be given to the following:
Viagra (Sildenafil citrate) has systemic vasodilatory properties and may augment the blood pressure lowering effect of other anti-hypertensive medications.
Patients on multiple antihypertensive medications were included in the pivotal clinical trials for Viagra (Sildenafil citrate) . In a separate drug interaction study, when amlodipine, 5 mg or 10 mg, and Viagra (Sildenafil citrate) , 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 ).
The safety of Viagra (Sildenafil citrate) is unknown in patients with bleeding disorders and patients with active peptic ulceration.
Viagra (Sildenafil citrate) 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).
The safety and efficacy of combinations of Viagra (Sildenafil citrate) with other treatments for erectile dysfunction have not been studied. Therefore, the use of such combinations is not recommended.
In humans, Viagra (Sildenafil citrate) has no effect on bleeding time when taken alone or with aspirin. studies with human platelets indicate that sildenafil potentiates the antiaggregatory effect of sodium nitroprusside (a nitric oxide donor). The combination of heparin and Viagra (Sildenafil citrate) had an additive effect on bleeding time in the anesthetized rabbit, but this interaction has not been studied in humans.
Physicians should discuss with patients the contraindication of Viagra (Sildenafil citrate) with regular and/or intermittent use of organic nitrates.
Physicians should advise patients of the potential for Viagra (Sildenafil citrate) to augment the blood pressure lowering effect of alpha-blockers and anti-hypertensive medications. Concomitant administration of Viagra (Sildenafil citrate) and an alpha-blocker may lead to symptomatic hypotension in some patients. Therefore, when Viagra (Sildenafil citrate) is co-administered with alpha-blockers, patients should be stable on alpha-blocker therapy prior to initiating Viagra (Sildenafil citrate) treatment and Viagra (Sildenafil citrate) should be initiated at the lowest dose.
Physicians should discuss with patients the potential cardiac risk of sexual activity in patients with preexisting cardiovascular risk factors. Patients who experience symptoms (e.g., angina pectoris, dizziness, nausea) upon initiation of sexual activity should be advised to refrain from further activity and should discuss the episode with their physician.
Physicians should advise patients to stop use of all PDE5 inhibitors, including Viagra (Sildenafil citrate) , 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 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. It is not possible to determine whether these events are related directly to the use of PDE5 inhibitors or to other factors. Physicians should also discuss with patients the increased risk of NAION in individuals who have already experienced NAION in one eye, including whether such individuals could be adversely affected by use of vasodilators, such as PDE5 inhibitors (see ).
Physicians should advise patients to stop taking PDE5 inhibitors, including Viagra (Sildenafil citrate) , and seek prompt medical attention in the event of sudden decrease or loss of hearing. These events, which may be accompanied by tinnitus and dizziness, have been reported in temporal association to the intake of PDE5 inhibitors, including Viagra (Sildenafil citrate) . It is not possible to determine whether these events are related directly to the use of PDE5 inhibitors or to other factors (see ).
Physicians should warn patients that prolonged erections greater than 4 hours and priapism (painful erections greater than 6 hours in duration) have been reported infrequently since market approval of Viagra (Sildenafil citrate) . In the event of an erection that persists longer than 4 hours, the patient should seek immediate medical assistance. If priapism is not treated immediately, penile tissue damage and permanent loss of potency may result.
Physicians should inform patients not to take Viagra (Sildenafil citrate) with other PDE5 inhibitors including REVATIO. Sildenafil is also marketed as REVATIO for the treatment of pulmonary arterial hypertension. The safety and efficacy of Viagra (Sildenafil citrate) with other PDE5 inhibitors, including REVATIO, have not been studied.
The use of Viagra (Sildenafil citrate) offers no protection against sexually transmitted diseases. Counseling of patients about the protective measures necessary to guard against sexually transmitted diseases, including the Human Immunodeficiency Virus (HIV), may be considered.
Sildenafil was not carcinogenic when administered to rats for 24 months at a dose resulting in total systemic drug exposure (AUCs) for unbound sildenafil and its major metabolite of 29- and 42-times, for male and female rats, respectively, the exposures observed in human males given the Maximum Recommended Human Dose (MRHD) of 100 mg. Sildenafil was not carcinogenic when administered to mice for 18–21 months at dosages up to the Maximum Tolerated Dose (MTD) of 10 mg/kg/day, approximately 0.6 times the MRHD on a mg/m basis.
Sildenafil was negative in bacterial and Chinese hamster ovary cell assays to detect mutagenicity, and human lymphocytes and mouse micronucleus assays to detect clastogenicity.
There was no impairment of fertility in rats given sildenafil up to 60 mg/kg/day for 36 days to females and 102 days to males, a dose producing an AUC value of more than 25 times the human male AUC.
There was no effect on sperm motility or morphology after single 100 mg oral doses of Viagra (Sildenafil citrate) in healthy volunteers.
Viagra (Sildenafil citrate) Adverse Reactions
Viagra (Sildenafil citrate) was administered to over 3700 patients (aged 19–87 years) during pre-marketing clinical trials worldwide. Over 550 patients were treated for longer than one year.
In placebo-controlled clinical studies, the discontinuation rate due to adverse events for Viagra (Sildenafil citrate) (2.5%) was not significantly different from placebo (2.3%). The adverse events were generally transient and mild to moderate in nature.
In trials of all designs, adverse events reported by patients receiving Viagra (Sildenafil citrate) were generally similar. In fixed-dose studies, the incidence of some adverse events increased with dose. The nature of the adverse events in flexible-dose studies, which more closely reflect the recommended dosage regimen, was similar to that for fixed-dose studies.
When Viagra (Sildenafil citrate) was taken as recommended (on an as-needed basis) in flexible-dose, placebo-controlled clinical trials, the following adverse events were reported:
Other adverse reactions occurred at a rate of >2%, but equally common on placebo: respiratory tract infection, back pain, flu syndrome, and arthralgia.
In fixed-dose studies, dyspepsia (17%) and abnormal vision (11%) were more common at 100 mg than at lower doses. At doses above the recommended dose range, adverse events were similar to those detailed above but generally were reported more frequently.
The following events occurred in <2% of patients in controlled clinical trials; a causal relationship to Viagra (Sildenafil citrate) is uncertain. Reported events include those with a plausible relation to drug use; omitted are minor events and reports too imprecise to be meaningful:
Body as a whole:
Cardiovascular:
Digestive:
Hemic and Lymphatic:
Metabolic and Nutritional:
Musculoskeletal
Nervous:
Respiratory:
Skin and Appendages:
Special Senses:
Urogenital:
Viagra (Sildenafil citrate) Overdosage
In studies with healthy volunteers of single doses up to 800 mg, adverse events were similar to those seen at lower doses but incidence rates and severities were increased.
In cases of overdose, standard supportive measures should be adopted as required. Renal dialysis is not expected to accelerate clearance as sildenafil is highly bound to plasma proteins and it is not eliminated in the urine.
Viagra (Sildenafil citrate) Dosage And Administration
For most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. However, Viagra (Sildenafil citrate) may be taken anywhere from 4 hours to 0.5 hour before sexual activity. Based on effectiveness and toleration, the dose may be increased to a maximum recommended dose of 100 mg or decreased to 25 mg. The maximum recommended dosing frequency is once per day.
The following factors are associated with increased plasma levels of sildenafil: age >65 (40% increase in AUC), hepatic impairment (e.g., cirrhosis, 80%), severe renal impairment (creatinine clearance <30 mL/min, 100%), and concomitant use of potent cytochrome P450 3A4 inhibitors [ketoconazole, itraconazole, erythromycin (182%), saquinavir (210%)]. Since higher plasma levels may increase both the efficacy and incidence of adverse events, a starting dose of 25 mg should be considered in these patients.
Ritonavir greatly increased the systemic level of sildenafil in a study of healthy, non-HIV infected volunteers (11-fold increase in AUC, see .) Based on these pharmacokinetic data, it is recommended not to exceed a maximum single dose of 25 mg of Viagra (Sildenafil citrate) in a 48 hour period.
Viagra (Sildenafil citrate) was shown to potentiate the hypotensive effects of nitrates and its administration in patients who use nitric oxide donors or nitrates in any form is therefore contraindicated.
When Viagra (Sildenafil citrate) is co-administered with an alpha-blocker, patients should be stable on alpha-blocker therapy prior to initiating Viagra (Sildenafil citrate) treatment and Viagra (Sildenafil citrate) should be initiated at the lowest dose (see ).
Viagra (Sildenafil citrate) How Supplied
Viagra (Sildenafil citrate) is supplied as blue, film-coated, rounded-diamond-shaped tablets containing sildenafil citrate equivalent to the nominally indicated amount of sildenafil as follows:
Viagra (Sildenafil citrate)
Viagra (Sildenafil citrate) Patient Summary Of Information About
This medicine can help many men when it is used as prescribed by their doctors. However, Viagra (Sildenafil citrate) is not for everyone. It is intended for use only by men who have a condition called erectile dysfunction.
Viagra (Sildenafil citrate) is a pill used to treat erectile dysfunction (impotence) in men. It can help many men who have erectile dysfunction get and keep an erection when they become sexually excited (stimulated).
You will not get an erection just by taking this medicine. Viagra (Sildenafil citrate) helps a man with erectile dysfunction get an erection only when he is sexually excited.
When a man is sexually excited, the penis rapidly fills with more blood than usual. The penis then expands and hardens. This is called an erection. After the man is done having sex, this extra blood flows out of the penis back into the body. The erection goes away. If an erection lasts for a long time (more than 6 hours), it can permanently damage your penis. You should call a doctor immediately if you ever have a prolonged erection that lasts more than 4 hours.
Some conditions and medicines interfere with this natural erection process. The penis cannot fill with enough blood. The man cannot have an erection. This is called erectile dysfunction if it becomes a frequent problem.
During sex, your heart works harder. Therefore sexual activity may not be advisable for people who have heart problems. Before you start any treatment for erectile dysfunction, ask your doctor if your heart is healthy enough to handle the extra strain of having sex. If you have chest pains, dizziness or nausea during sex, stop having sex and immediately tell your doctor you have had this problem.
Viagra (Sildenafil citrate) enables many men with erectile dysfunction to respond to sexual stimulation. When a man is sexually excited, Viagra (Sildenafil citrate) helps the penis fill with enough blood to cause an erection. After sex is over, the erection goes away.
As noted above (), ask your doctor if your heart is healthy enough for sexual activity.
Nitrates are also found in recreational drugs such as amyl nitrate or nitrite ("poppers"). If you are not sure if any of your medicines contain nitrates, or if you do not understand what nitrates are, ask your doctor or pharmacist.
Viagra (Sildenafil citrate) is only for patients with erectile dysfunction. Viagra (Sildenafil citrate) is not for newborns, children, or women. Do not let anyone else take your Viagra (Sildenafil citrate) . Viagra (Sildenafil citrate) must be used only under a doctor's supervision.
Only your doctor can decide if Viagra (Sildenafil citrate) is right for you. Viagra (Sildenafil citrate) can cause mild, temporary lowering of your blood pressure. You will need to have a thorough medical exam to diagnose your erectile dysfunction and to find out if you can safely take Viagra (Sildenafil citrate) alone or with your other medicines. Your doctor should determine if your heart is healthy enough to handle the extra strain of having sex.
Be sure to tell your doctor if you:
Some medicines can change the way Viagra (Sildenafil citrate) works. Tell your doctor about you are taking. Do not start or stop taking any medicines before checking with your doctor or pharmacist. This includes prescription and nonprescription medicines or remedies:
Viagra (Sildenafil citrate) comes in different doses (25 mg, 50 mg and 100 mg). If you do not get the results you expect, talk with your doctor. You and your doctor can determine the dose that works best for you.
Your doctor may prescribe a lower dose of Viagra (Sildenafil citrate) in certain circumstances. For example:
Take Viagra (Sildenafil citrate) about one hour before you plan to have sex. Beginning in about 30 minutes and for up to 4 hours, Viagra (Sildenafil citrate) can help you get an erection if you are sexually excited. If you take Viagra (Sildenafil citrate) after a high-fat meal (such as a cheeseburger and french fries), the medicine may take a little longer to start working. Viagra (Sildenafil citrate) can help you get an erection when you are sexually excited. You will not get an erection just by taking the pill.
Like all medicines, Viagra (Sildenafil citrate) can cause some side effects. These effects are usually mild to moderate and usually don't last longer than a few hours. Some of these side effects are more likely to occur with higher doses. The most common side effects of Viagra (Sildenafil citrate) are headache, flushing of the face, and upset stomach. Less common side effects that may occur are temporary changes in color vision (such as trouble telling the difference between blue and green objects or having a blue color tinge to them), eyes being more sensitive to light, or blurred vision.
In rare instances, men taking PDE5 inhibitors (oral erectile dysfunction medicines, including Viagra (Sildenafil citrate) ) reported a sudden decrease or loss of vision in one or both eyes. It is not possible to determine whether these events are related directly to these medicines, to other factors such as high blood pressure or diabetes, or to a combination of these. If you experience sudden decrease or loss of vision, stop taking PDE5 inhibitors, including Viagra (Sildenafil citrate) , and call a doctor right away.
In rare instances, men have reported an erection that lasts many hours. You should call a doctor immediately if you ever have an erection that lasts more than 4 hours. If not treated right away, permanent damage to your penis could occur (see ).
Sudden loss or decrease in hearing, sometimes with ringing in the ears and dizziness, has been rarely reported in people taking PDE5 inhibitors, including Viagra (Sildenafil citrate) . It is not possible to determine whether these events are related directly to the PDE5 inhibitors, to other diseases or medications, to other factors, or to a combination of factors. If you experience these symptoms, stop taking Viagra (Sildenafil citrate) and contact a doctor right away.
Heart attack, stroke, irregular heart beats, and death have been reported rarely in men taking Viagra (Sildenafil citrate) . Most, but not all, of these men had heart problems before taking this medicine. It is not possible to determine whether these events were directly related to Viagra (Sildenafil citrate) .
Viagra (Sildenafil citrate) may cause other side effects besides those listed on this sheet. If you want more information or develop any side effects or symptoms you are concerned about, call your doctor.
In case of accidental overdose, call your doctor right away.
Keep Viagra (Sildenafil citrate) out of the reach of children. Keep Viagra (Sildenafil citrate) in its original container. Store at 25°C (77°F); excursions permitted to 15–30°C (59–86°F) [see USP Controlled Room Temperature].
Viagra (Sildenafil citrate) is a prescription medicine used to treat erectile dysfunction. Only your doctor can decide if it is right for you. This sheet is only a summary. If you have any questions or want more information about Viagra (Sildenafil citrate) , talk with your doctor or pharmacist, visit www.Viagra (Sildenafil citrate) .com, or call 1-888-4Viagra (Sildenafil citrate) .
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Viagra (Sildenafil citrate) Principal Display Panel - Mg / Tablet Bottle Label
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