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STENDRA is a phosphodiesterase 5 (PDE5) inhibitor indicated for the treatment of erectile dysfunction
Dosage
Erectile Dysfunction
The recommended starting dose is 100 mg. STENDRA should be taken orally as needed as early as approximately 15 minutes before sexual activity.
Based on individual efficacy and tolerability, the dose may be increased to 200 mg taken as early as approximately 15 minutes before sexual activity, or decreased to 50 mg taken approximately 30 minutes before sexual activity. The lowest dose that provides benefit should be used.
The maximum recommended dosing frequency is once per day. Sexual stimulation is required for a response to treatment.
Concomitant Medications
Alpha-Blockers
If STENDRA is co-administered with an alpha-blocker, patients should be stable on alpha-blocker therapy prior to initiating treatment with STENDRA, and STENDRA should be initiated at the 50 mg dose.
CYP3A4 Inhibitors
For patients taking concomitant strong CYP3A4 inhibitors (including ketoconazole, ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, and telithromycin), do not use STENDRA.
For patients taking concomitant moderate CYP3A4 inhibitors (including erythromycin, amprenavir, aprepitant, diltiazem, fluconazole, fosamprenavir, and verapamil), the maximum recommended dose of STENDRA is 50 mg, not to exceed once every 24 hours
DOSAGE FORMS AND STRENGTHS
STENDRA (avanafil) is supplied as oval, pale yellow tablets containing 50 mg, 100 mg, or 200 mg avanafil debossed with dosage strength.
Off-Label Use and Dosage (Adult)
Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Avanafil in adult patients.
Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Avanafil in adult patients.
Pediatric Indications and Dosage
FDA-Labeled Indications and Dosage (Pediatric)
There is limited information regarding FDA-Labeled Use of Avanafil in pediatric patients.
Off-Label Use and Dosage (Pediatric)
Guideline-Supported Use
There is limited information regarding Off-Label Guideline-Supported Use of Avanafil in pediatric patients.
Non–Guideline-Supported Use
There is limited information regarding Off-Label Non–Guideline-Supported Use of Avanafil in pediatric patients.
Contraindications
Nitrates
Administration of STENDRA with any form of organic nitrates, either regularly and/or intermittently, is contraindicated. Consistent with its known effects on the nitric oxide/cyclic guanosine monophosphate (cGMP) pathway, STENDRA has been shown to potentiate the hypotensive effects of nitrates.
In a patient who has taken STENDRA, where nitrate administration is deemed medically necessary in a life-threatening situation, at least 12 hours should elapse after the last dose of STENDRA before nitrate administration is considered. In such circumstances, nitrates should only be administered under close medical supervision with appropriate hemodynamic monitoring.
Hypersensitivity Reactions
STENDRA is contraindicated in patients with a known hypersensitivity to any component of the tablet. Hypersensitivity reactions have been reported, including pruritis and eyelid swelling.
Warnings
Evaluation of erectile dysfunction (ED) should include an appropriate medical assessment to identify potential underlying causes, as well as treatment options.
Before prescribing STENDRA, it is important to note the following:
Cardiovascular Risks
There is a potential for cardiac risk during sexual activity in patients with pre-existing cardiovascular disease. Therefore, treatments for ED, including STENDRA, should not be used in men for whom sexual activity is inadvisable because of their underlying cardiovascular status.
Patients with left ventricular outflow obstruction (e.g., aortic stenosis, idiopathic hypertrophic subaortic stenosis) and those with severely impaired autonomic control of blood pressure can be particularly sensitive to the actions of vasodilators, including STENDRA.
The following groups of patients were not included in clinical safety and efficacy trials for STENDRA, and therefore until further information is available, STENDRA is not recommended for the following groups:
Patients with resting hypotension (blood pressure less than 90/50 mmHg) or hypertension (blood pressure greater than 170/100 mmHg);
Patients with unstable angina, angina with sexual intercourse, or New York Heart Association Class 2 or greater congestive heart failure.
As with other PDE5 inhibitors STENDRA has systemic vasodilatory properties and may augment the blood pressure-lowering effect of other anti-hypertensive medications. STENDRA 200 mg resulted in transient decreases in sitting blood pressure in healthy volunteers of 8.0 mmHg systolic and 3.3 mmHg diastolic [see CLINICAL PHARMACOLOGY (12.2)], with the maximum decrease observed at 1 hour after dosing. While this normally would be expected to be of little consequence in most patients, prior to prescribing STENDRA, physicians should carefully consider whether patients with underlying cardiovascular disease could be affected adversely by such vasodilatory effects, especially in combination with sexual activity.
Concomitant Use of CYP3A4 Inhibitors
STENDRA metabolism is principally mediated by the CYP450 isoform 3A4 (CYP3A4). Inhibitors of CYP3A4 may reduce STENDRA clearance and increase plasma concentrations of avanafil.
For patients taking concomitant strong CYP3A4 inhibitors (including ketoconazole, ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, and telithromycin), do not use STENDRA.
For patients taking concomitant moderate CYP3A4 inhibitors (including erythromycin, amprenavir, aprepitant, diltiazem, fluconazole, fosamprenavir, and verapamil), the maximum recommended dose of STENDRA is 50 mg, not to exceed once every 24 hours.
Prolonged Erection
Prolonged erection greater than 4 hours and priapism (painful erections greater than 6 hours in duration) have been reported with other PDE5 inhibitors. In the event of an erection that persists longer than 4 hours, the patient should seek immediate medical assistance. If not treated immediately, penile tissue damage and permanent loss of potency could result.
STENDRA 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).
Effects on Eye
Physicians should advise patients to stop use of all PDE5 inhibitors, including STENDRA, 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 postmarketing 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 study evaluated whether recent use of PDE5 inhibitors, as a class, was associated with acute onset of NAION. The results suggest an approximate 2-fold increase in the risk of NAION within 5 half-lives of PDE5 inhibitor use. From this information, it is not possible to determine whether these events are related directly to the use of PDE5 inhibitors or to other factors.
Physicians should consider whether their patients with underlying NAION risk factors could be adversely affected by use of PDE5 inhibitors. Individuals who have already experienced NAION are at increased risk of NAION recurrence. Therefore, PDE5 inhibitors, including STENDRA, should be used with caution in these patients and only when the anticipated benefits 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 STENDRA, for this uncommon condition.
Sudden Hearing Loss
Use of PDE5 inhibitors has been associated with sudden decrease or loss of hearing, which may be accompanied by tinnitus or dizziness. It is not possible to determine whether these events are related directly to the use of PDE5 inhibitors or to other factors. Patients experiencing these symptoms should be advised to stop taking STENDRA and seek prompt medical attention.
Alpha-Blockers and Other Antihypertensives
Physicians should discuss with patients the potential for STENDRA to augment the blood pressure-lowering effect of alpha-blockers and other antihypertensive medications.
Caution is advised when PDE5 inhibitors are co-administered with alpha-blockers. Phosphodiesterase type 5 inhibitors, including STENDRA, 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 leading to symptomatic hypotension (e.g., dizziness, lightheadedness, fainting).
Consideration should be given to the following:
Patients should be stable on alpha-blocker therapy prior to initiating treatment with a PDE5 inhibitor. Patients who demonstrate hemodynamic instability on alpha-blocker therapy alone are at increased risk of symptomatic hypotension with concomitant use of PDE5 inhibitors.
In those patients who are stable on alpha-blocker therapy, PDE5 inhibitors should be initiated at the lowest dose (STENDRA 50 mg).
In those patients already taking an optimized dose of a PDE5 inhibitor, alpha-blocker therapy should be initiated at the lowest dose. 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.
Alcohol
Patients should be made aware that both alcohol and PDE5 inhibitors including STENDRA act as vasodilators. When vasodilators are taken in combination, blood-pressure-lowering effects of each individual compound may be increased. Therefore, physicians should inform patients that substantial consumption of alcohol (e.g., greater than 3 units) in combination with STENDRA may increase the potential for orthostatic signs and symptoms, including increase in heart rate, decrease in standing blood pressure, dizziness, and headache.
Combination with Other PDE5 Inhibitors or Erectile Dysfunction Therapies
The safety and efficacy of combinations of STENDRA with other treatments for ED has not been studied. Therefore, the use of such combinations is not recommended.
Effects on Bleeding
The safety of STENDRA is unknown in patients with bleeding disorders and patients with active peptic ulceration. In vitro studies with human platelets indicate that STENDRA potentiates the anti-aggregatory effect of sodium nitroprusside (a nitric oxide [NO] donor).
Counseling Patients about Sexually Transmitted Diseases
The use of STENDRA offers no protection against sexually transmitted diseases. Counseling patients about the protective measures necessary to guard against sexually transmitted diseases, including Human Immunodeficiency Virus (HIV), should be considered.
Adverse Reactions
Clinical Trials Experience
Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
STENDRA was administered to 2215 men during clinical trials. In trials of STENDRA for use as needed, a total of 493 patients were exposed for greater than or equal to 6 months, and 153 patients were treated for greater than or equal to 12 months.
In three randomized, double-blind, placebo-controlled trials lasting up to 3 months in duration, the mean age of patients was 56.4 years (range from 23 to 88 years). 83.9% of patients were White, 13.8% were Black, 1.4% Asian, and < 1% Hispanic. 41.1% were current or previous smokers. 30.6% had diabetes mellitus.
The discontinuation rate due to adverse reactions for patients treated with STENDRA 50 mg, 100 mg, or 200 mg was 1.4%, 2.0%, and 2.0%, respectively, compared to 1.7% for placebo-treated patients.
Table 1 presents the adverse reactions reported when STENDRA was taken as recommended (on an as-needed basis) from these 3 clinical trials.
This image is provided by the National Library of Medicine.
In an open-label, long-term extension study of two of these randomized, double-blind, placebo-controlled trials, the total duration of treatment was up to 52 weeks. Among the 712 patients who participated in this open-label extension study, the mean age of the population was 56.4 years (range from 23 to 88 years). The discontinuation rate due to adverse reactions for patients treated with STENDRA (50 mg, 100 mg, or 200 mg) was 2.8%.
In this extension trial, all eligible patients were initially assigned to STENDRA 100 mg. At any point during the trial, patients could request to have their dose of STENDRA increased to 200 mg or decreased to 50 mg based on their individual response to treatment. In total, 536 (approximately 75%) patients increased their dose to 200 mg and 5 (less than 1%) patients reduced their dose to 50 mg.
Table 2 presents the adverse reactions reported when STENDRA was taken as recommended (on an as-needed basis) in this open-label extension trial.
This image is provided by the National Library of Medicine.
The following events occurred in less than 1% of patients in the three placebo-controlled 3-month clinical trials and/or the open-label, long-term extension study lasting 12 months. A causal relationship to STENDRA is uncertain. Excluded from this list are those events that were minor, those with no plausible relation to drug use, and reports too imprecise to be meaningful.
In an additional randomized, double-blind, placebo-controlled study lasting up to 3 months in 298 men who had undergone bilateral nerve-sparing radical prostatectomy for prostate cancer, the mean age of patients was 58.4 years (range 40 – 70). Table 3 presents the adverse reactions reported in this study.
This image is provided by the National Library of Medicine.
A randomized, double-blind, placebo-controlled 2 months study was conducted in 435 subjects with a mean age of 58.2 years (range 24 to 86 years) to determine the time to onset of effect of STENDRA, defined as the time to the first occurrence of an erection sufficient for sexual intercourse. Table 4 presents the adverse reactions occurring in ≥ 2% of subjects treated with STENDRA.
This image is provided by the National Library of Medicine.
Across all trials with any STENDRA dose, 1 subject reported a change in color vision.
Postmarketing Experience
Ophthalmologic:
Non-arteritic anterior ischemic optic neuropathy (NAION), a cause of decreased vision including permanent loss of vision, has been reported rarely post-marketing in temporal association with the use of phosphodiesterase type 5 (PDE5) inhibitors. Most, but not all, of these patients had underlying anatomic or vascular risk factors for developing NAION, including but not necessarily limited to: low cup to disc ratio ("crowded disc"), age over 50, diabetes, hypertension, coronary artery disease, hyperlipidemia, and smoking. It is not possible to determine whether these events are related directly to the use of PDE5 inhibitors, to the patient's underlying vascular risk factors or anatomical defects, to a combination of these factors, or to other factors.
Drug Interactions
Potential for Pharmacodynamic Interactions with STENDRA
Nitrates
Administration of STENDRA to patients who are using any form of organic nitrate is contraindicated. In a clinical pharmacology trial, STENDRA was shown to potentiate the hypotensive effect of nitrates. In a patient who has taken STENDRA, where nitrate administration is deemed medically necessary in a life-threatening situation, at least 12 hours should elapse after the last dose of STENDRA before nitrate administration is considered. In such circumstances, nitrates should only be administered under close medical supervision with appropriate hemodynamic monitoring.
Alpha-Blockers
Caution is advised when PDE5 inhibitors are co-administered with alpha-blockers. PDE5 inhibitors, including STENDRA, 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 leading to symptomatic hypotension (e.g., dizziness, lightheadedness, fainting).
Antihypertensives
PDE5 inhibitors, including STENDRA, are mild systemic vasodilators. A clinical pharmacology trial was conducted to assess the effect of STENDRA on the potentiation of the blood pressure-lowering effects of selected antihypertensive medications (amlodipine and enalapril). Additional reductions in blood pressure of 3 to 5 mmHg occurred following co-administration of a single 200 mg dose of STENDRA with these agents compared with placebo.
Alcohol
Both alcohol and PDE5 inhibitors, including STENDRA, act as vasodilators. When vasodilators are taken in combination, blood pressure-lowering effects of each individual compound may be increased. Substantial consumption of alcohol (e.g., greater than 3 units) in combination with STENDRA can increase the potential for orthostatic signs and symptoms, including increase in heart rate, decrease in standing blood pressure, dizziness, and headache.
Potential for Other Drugs to Affect STENDRA
STENDRA is a substrate of and predominantly metabolized by CYP3A4. Studies have shown that drugs that inhibit CYP3A4 can increase avanafil exposure.
Strong CYP3A4 Inhibitors
Ketoconazole (400 mg daily), a selective and strong inhibitor of CYP3A4, increased STENDRA 50 mg single-dose systemic exposure (AUC) and maximum concentration (Cmax) equal to 13-fold and 3-fold, respectively, and prolonged the half-life of avanafil to approximately 9 hours. Other potent inhibitors of CYP3A4 (e.g., itraconazole, clarithromycin, nefazadone, ritonavir, saquinavir, nelfinavir, indinavir, atanazavir, and telithromycin) would be expected to have similar effects. Do not use STENDRA in patients taking strong CYP3A4 inhibitors .
HIV Protease inhibitor — Ritonavir (600 mg twice daily), a strong CYP3A4 inhibitor, which also inhibits CYP2C9, increased STENDRA 50 mg single-dose Cmax and AUC equal to approximately 2-fold and 13-fold, and prolonged the half-life of avanafil to approximately 9 hours in healthy volunteers. Do not use STENDRA in patients taking ritonavir.
Moderate CYP3A4 Inhibitors
Erythromycin (500 mg twice daily) increased STENDRA 200 mg single-dose Cmax and AUC equal to approximately 2-fold and 3-fold, respectively, and prolonged the half-life of avanafil to approximately 8 hours in healthy volunteers. Moderate CYP3A4 inhibitors (e.g., erythromycin, amprenavir, aprepitant, diltiazem, fluconazole, fosamprenavir, and verapamil) would be expected to have similar effects. Consequently, the maximum recommended dose of STENDRA is 50 mg, not to exceed once every 24 hours for patients taking concomitant moderate CYP3A4 inhibitors.
Although specific interactions have not been studied, other CYP3A4 inhibitors, including grapefruit juice are likely to increase avanafil exposure.
Weak CYP3A4 Inhibitors
No in vivo drug-drug interaction studies with weak CYP3A4 inhibitors were conducted.
CYP3A4 Substrate
When administered with STENDRA 200 mg, amlodipine (5 mg daily) increased the Cmax and AUC of avanafil by approximately 22% and 70%, respectively. The half-life of STENDRA was prolonged to approximately 10 hrs. The Cmax and AUC of amlodipine decreased by approximately 9% and 4%, respectively.
Cytochrome P450 Inducers
The potential effect of CYP inducers on the pharmacokinetics of avanafil was not evaluated. The concomitant use of STENDRA and CYP inducers is not recommended.
Potential for STENDRA to Affect Other Drugs
In vitro studies
Avanafil had no effect on CYP1A1/2, 2A6, 2B6, and 2E1 (IC50 greater than 100 micromolar) and weak inhibitory effects toward other isoforms (CYP2C8, 2C9, 2C19, 2D6, 3A4). Major circulating metabolites of avanafil (M4 and M16) had no effect on CYPs 1A, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, and 3A4. Avanafil and its metabolites (M4 and M16) are unlikely to cause clinically significant inhibition of CYPs 1A, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, or 3A4.
In vivo studies
Warfarin —A single 200 mg dose of STENDRA did not alter the changes in PT or INR induced by warfarin, and did not affect collagen-induced platelet aggregation or the AUC or Cmax of R- or S-warfarin, a 2C9 substrate.
Desipramine — A single STENDRA 200 mg dose increased AUC and Cmax of a single 50 mg dose of desipramine, a CYP2D6 substrate, by 5.7% and 5.2%, respectively.
Omeprazole — A single STENDRA 200 mg dose increased AUC and Cmax of a single 40 mg dose of omeprazole, a CYP2C19 substrate, given once daily for 8 days by 5.9% and 8.6%, respectively.
Rosiglitazone — A single STENDRA 200 mg dose increased AUC by 2.0% and decreased Cmax by 14% of a single 8 mg dose of rosiglitazone, a CYP2C8 substrate.
Amlodipine — A single STENDRA 200 mg dose did not affect the pharmacokinetics of amlodipine (5 mg daily), a CYP3A4 substrate [see DOSAGE AND ADMINISTRATION (2.3)].
Alcohol — A single oral dose of STENDRA 200 mg did not affect alcohol (0.5 g ethanol/kg) plasma concentrations
