Men's Health
However, sildenafil may be taken anywhere from 4 hours to 0.5 hour before sexual activity.
| Use Case | Description | Common Dosage | Notes |
|---|---|---|---|
| Erectile Dysfunction | Facilitates blood flow to improve erection | 50-100 mg | Taken 30-60 mins before activity |
| Pulmonary Hypertension | Low doses to relax blood vessels in lungs | 20 mg TID | Under medical supervision |
| Off-label Uses | Mountain sickness, Raynaud's phenomenon | Varies | Not FDA approved for these |
Your doctor may increase the dose to a maximum recommended dose of 100 mg or decreased it to 25 mg. Sildenafil is to be taken only once per day.
Author information
For the treatment of pulmonary arterial hypertension (PAH): TABLETS and ORAL SOLUTION: The recommended dose of sildenafil is 20 mg three times a day.
| Product | Dosage | Quantity + Bonus | Price | |
|---|---|---|---|---|
| Kamagra Oral Jelly | 100mg | 220 + 18 Sachets | 662.24€ 630.70€ | |
| Viagra Generic | 25mg | 180 + 6 Pills | 154.93€ 147.55€ | |
| Viagra Generic | 200mg | 10 Pills | 40.96€ 39.01€ | |
| Kamagra Oral Jelly | 100mg | 21 Sachets | 95.92€ 91.35€ | |
| Viagra Generic | 25mg | 10 Pills | 25.19€ 23.99€ | |
| Viagra Generic | 100mg | 10 Pills | 28.91€ 27.53€ | |
| Kamagra | 100mg | 120 + 6 Pills | 330.74€ 314.99€ | |
| Kamagra Polo | 100mg | 180 + 8 Pills | 446.52€ 425.26€ | |
| Kamagra Polo | 100mg | 84 + 4 Pills | 244.49€ 232.85€ | |
| Kamagra Polo | 100mg | 272 + 12 Pills | 622.94€ 593.28€ | |
| Kamagra Oral Jelly | 100mg | 10 Sachets | 54.55€ 51.95€ |
Doses higher than 20 mg three times a day is not recommended.
8.7 Hepatic Impairment
Approval: 1998INDICATIONS AND USAGESildenafil is a phosphodiesterase-5 (PDE5) inhibitor indicated for the treatment of erectile dysfunction tablet sildenafil 50 mg (ED) (1)DOSAGE AND ADMINISTRATIONFor most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. However, sildenafil tablets may be taken anywhere from 30 minutes to 4 hours before sexual activity (2.1)Based on effectiveness and toleration, may increase to a maximum of 100 mg or decrease to 25 mg (2.1)Maximum recommended dosing frequency is once per day (2.1)DOSAGE FORMS AND STRENGTHSTablets: 25 mg, 50 mg, 100 mg (3)CONTRAINDICATIONSAdministration of sildenafil tablets to patients using nitric oxide donors, such as organic nitrates or organic nitrites in any form. Sildenafil tablets was shown to potentiate the hypotensive effect of nitrates (4.1, 7.1, 12.2)Known hypersensitivity to sildenafil or any component of tablet (4.2)Administration with guanylate cyclase (GC) stimulators, such as riociguat (4.3)WARNINGS AND PRECAUTIONSPatients should not use sildenafil if sexual activity is inadvisable due to cardiovascular status (5.1)Patients should seek emergency treatment if an erection lasts >4 hours. Use sildenafil with caution in patients predisposed to priapism (5.2)Patients should stop sildenafil and seek medical care if a sudden loss of vision occurs in one or both eyes, which could be a sign of non arteritic anterior ischemic optic neuropathy (NAION). Sildenafil should be used with caution, and only when the anticipated benefits outweigh the risks, in patients with a history of NAION.
Allergy warning
Patients with a “crowded” optic disc may also be at an increased risk of NAION. (5.3)Patients should stop sildenafil and seek prompt medical attention in the event of sudden decrease or loss of hearing (5.4)Caution is advised when sildenafil is co-administered with alpha-blockers or anti-hypertensives. Concomitant use may lead to hypotension (5.5)Decreased blood pressure, syncope, and prolonged erection may occur at higher sildenafil exposures. In patients taking strong CYP inhibitors, such as ritonavir, sildenafil exposure is increased. Decrease in sildenafil dosage is recommended (2.4, 5.6)ADVERSE REACTIONSMost common sildenafil citrate tablets 50mg adverse reactions (> 2%) include headache, flushing, dyspepsia, abnormal vision, nasal congestion, back pain, myalgia, nausea, dizziness and rash (6.1)To report SUSPECTED ADVERSE REACTIONS, contact Aurobindo Pharma USA, Inc.
Is it OK to take 100 mg of Teva sildenafil?
at 1-866-850-2876 or FDA at 1-800-FDA-1088 or INTERACTIONSSildenafil can potentiate the hypotensive effects of nitrates, alpha blockers, and anti-hypertensives (4.1, 5.5, 7.1, 7.2, 7.3, 12.2)With concomitant use of alpha blockers, initiate sildenafil at 25 mg dose (2.3)CYP3A4 inhibitors (e.g., ritonavir, ketoconazole, itraconazole, erythromycin): Increase sildenafil exposure (2.4, 7.4, 12.3)Erythromycin or strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, saquinavir): Consider a starting dose of 25 mg (2.4, 7.4)Ritonavir: Do not exceed a maximum single dose of 25 mg in a 48 hour period (2.4, 5.6)USE IN SPECIFIC POPULATIONSSee 17 for PATIENT COUNSELING INFORMATION and FDA-approved patient labeling.Revised: 5/2023 Sildenafil is a phosphodiesterase-5 (PDE5) inhibitor indicated for the treatment of erectile dysfunction (ED) (1) For most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. However, sildenafil tablets may be taken anywhere from 30 minutes to 4 hours before sexual activity (2.1) Based on effectiveness and toleration, may increase to a maximum of 100 mg or decrease to 25 mg (2.1) Maximum recommended dosing frequency is once per day (2.1) Tablets: 25 mg, 50 mg, 100 mg (3) Administration of sildenafil tablets to patients using nitric oxide donors, such as organic nitrates or organic nitrites in any form. Sildenafil tablets was shown to potentiate the hypotensive effect of nitrates (4.1, 7.1, 12.2) Known hypersensitivity to sildenafil or any component of tablet (4.2) Administration with guanylate cyclase (GC) stimulators, such as riociguat (4.3) Patients should not use sildenafil if sexual activity is inadvisable due to cardiovascular status (5.1) Patients should seek emergency treatment if an erection lasts >4 hours. Use sildenafil with caution in patients predisposed to priapism (5.2) Patients should stop sildenafil and seek medical care if a sudden loss of vision occurs in one or both eyes, which could be a sign of non arteritic anterior ischemic optic neuropathy (NAION). Patients should stop sildenafil and seek prompt medical attention in the event of sudden decrease or loss of hearing (5.4) Caution is advised when sildenafil is co-administered with alpha-blockers or anti-hypertensives. INJECTABLE: The recommended dose is 10 mg (12.5 mL) given as an injection into the vein (IV) three times a day. If you take too much this medication, call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away. If this medication is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if overdose is suspected, seek emergency medical attention. Store at room temperature away from excessive heat or moisture.
5.3 Effects on the Eye
However, sildenafil may be taken anywhere from 4 hours to 0.5 hour before sexual activity. Your doctor may increase the dose to a maximum recommended dose of 100 mg or decreased it to 25 mg. Sildenafil is to be taken only once per day. For the treatment of pulmonary arterial hypertension (PAH): TABLETS and ORAL SOLUTION: The recommended dose of sildenafil is 20 mg three times a day. Doses higher than 20 mg three times a day is not recommended.
Other Medical Problems
INJECTABLE: The recommended dose is 10 mg (12.5 mL) given as an injection into the vein (IV) three times a day. If you take too much this medication, call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away. If this medication is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if overdose is suspected, seek emergency medical attention. Store at room temperature away from excessive heat or moisture.
Sildenafil Citrate
The pill with imprint 100 (White, Four-sided, 14 mm) has been identified as Sildenafil Citrate 100 mg and is used for Erectile Dysfunction, and Pulmonary Arterial Hypertension. It belongs to the drug classes agents for pulmonary hypertension, impotence medications and is not a controlled substance. 2, aluminum oxide Note: Inactive ingredients may vary. NDC Code(s): 65862-689-01, 65862-689-05, 65862-689-30, 65862-689-99, view more65862-690-01, 65862-690-05, 65862-690-30, 65862-690-99, 65862-691-01, 65862-691-05, 65862-691-30 If you are a consumer or patient please visit this version. See full prescribing information for SILDENAFIL TABLETS.SILDENAFIL tablets, for oral useInitial U.S. The pill with imprint 100 (White, Four-sided, 14 mm) has been identified as Sildenafil Citrate 100 mg and is used for Erectile Dysfunction, and Pulmonary Arterial Hypertension. It belongs to the drug classes agents for pulmonary hypertension, impotence medications and is not a controlled substance.
More about sildenafil
Concomitant use may lead to hypotension (5.5) Decreased blood pressure, syncope, and prolonged erection may occur at higher sildenafil exposures. Decrease in sildenafil dosage is recommended (2.4, 5.6) Most common adverse reactions (> 2%) include headache, flushing, dyspepsia, abnormal vision, nasal congestion, back pain, myalgia, nausea, dizziness and rash (6.1) Sildenafil can potentiate the hypotensive effects of nitrates, alpha blockers, and anti-hypertensives (4.1, 5.5, 7.1, 7.2, 7.3, 12.2) With concomitant use of alpha blockers, initiate sildenafil at 25 mg dose (2.3) CYP3A4 inhibitors (e.g., ritonavir, ketoconazole, itraconazole, erythromycin): Increase sildenafil exposure (2.4, 7.4, 12.3) Erythromycin or strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, saquinavir): Consider a starting dose of 25 mg (2.4, 7.4) Ritonavir: Do not exceed a maximum single dose of 25 mg in a 48 hour period (2.4, 5.6) See 17 for PATIENT COUNSELING INFORMATION and FDA-approved patient labeling. Table of Contents FULL PRESCRIBING INFORMATION: CONTENTS*1 INDICATIONS AND USAGE2 DOSAGE AND ADMINISTRATION2.1 Dosage Information2.2 Use with Food2.3 Dosage Adjustments in Specific Situations2.4 Dosage Adjustments Due to Drug Interactions2.5 Dosage Adjustments in Special Populations3 DOSAGE FORMS AND STRENGTHS4 CONTRAINDICATIONS4.1 Nitrates4.2 Hypersensitivity Reactions4.3 Concomitant Guanylate Cyclase (GC) Stimulators5 WARNINGS AND PRECAUTIONS5.1 Cardiovascular5.2 Prolonged Erection and Priapism5.3 Effects on the Eye5.4 Hearing Loss5.5 Hypotension when Co-administered with Alpha-blockers or Anti-hypertensives5.6 Adverse Reactions with the Concomitant Use of Ritonavir5.7 Combination with other PDE5 Inhibitors or Other Erectile Dysfunction Therapies5.8 Effects on Bleeding5.9 Counseling Patients About Sexually Transmitted Diseases6 ADVERSE REACTIONS6.1 Clinical Trials Experience6.2 Postmarketing Experience7 DRUG INTERACTIONS7.1 Nitrates7.2 Alpha-blockers7.3 Amlodipine7.4 Ritonavir and Other CYP3A4 Inhibitors7.5 Alcohol8 USE IN SPECIFIC POPULATIONS8.1 Pregnancy8.2 Lactation8.4 Pediatric Use8.5 Geriatric Use8.6 Renal Impairment8.7 Hepatic Impairment10 OVERDOSAGE11 DESCRIPTION12 CLINICAL PHARMACOLOGY12.1 Mechanism of Action12.2 Pharmacodynamics12.3 Pharmacokinetics13 NONCLINICAL TOXICOLOGY13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility14 CLINICAL STUDIES16 HOW SUPPLIED/STORAGE AND HANDLING17 PATIENT COUNSELING INFORMATION*Sections or subsections omitted from the full prescribing information are not listed. 2 DOSAGE AND ADMINISTRATION 2.1 Dosage InformationFor most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. However, sildenafil tablets may be taken anywhere from 30 minutes to 4 hours before sexual activity.
How it works for PAH
The maximum recommended dosing frequency is once per day.Based on effectiveness and toleration, the dose may be increased to a maximum recommended dose of 100 mg or decreased to 25 mg.2.3 Dosage Adjustments in Specific SituationsSildenafil tablets was shown to potentiate the hypotensive effects of nitrates and its administration in patients who use nitric oxide donors such as organic nitrates or organic nitrites in any form is therefore contraindicated [see Contraindications (4.1), Drug Interactions (7.1), and Clinical Pharmacology (12.2)].When sildenafil tablets are co-administered with an alpha-blocker, patients should be stable on alpha-blocker therapy prior to initiating sildenafil tablets treatment and sildenafil tablets should be initiated at 25 mg [see Warnings and Precautions (5.5), Drug Interactions (7.2), and Clinical Pharmacology (12.2)].2.4 Dosage Adjustments Due to Drug InteractionsRitonavirThe recommended dose for ritonavir-treated patients is 25 mg prior to sexual activity and the recommended maximum dose is 25 mg within a 48 hour period because concomitant administration increased the blood levels of sildenafil by 11-fold [see Warnings and Precautions (5.6), Drug Interactions (7.4), and Clinical Pharmacology (12.3)].CYP3A4 InhibitorsConsider a starting dose of 25 mg in patients treated with strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, or saquinavir) or erythromycin.
Viagra Super Active
2, aluminum oxide Note: Inactive ingredients may vary. NDC Code(s): 65862-689-01, 65862-689-05, 65862-689-30, 65862-689-99, view more65862-690-01, 65862-690-05, 65862-690-30, 65862-690-99, 65862-691-01, 65862-691-05, 65862-691-30 If you are a consumer or patient please visit this version. See full prescribing information for SILDENAFIL TABLETS.SILDENAFIL tablets, for oral useInitial U.S. Approval: 1998INDICATIONS AND USAGESildenafil is a phosphodiesterase-5 (PDE5) inhibitor indicated for the treatment of erectile dysfunction tablet sildenafil 50 mg (ED) (1)DOSAGE AND ADMINISTRATIONFor most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. However, sildenafil tablets may be taken anywhere from 30 minutes to 4 hours before sexual activity (2.1)Based on effectiveness and toleration, may increase to a maximum of 100 mg or decrease to 25 mg (2.1)Maximum recommended dosing frequency is once per day (2.1)DOSAGE FORMS AND STRENGTHSTablets: 25 mg, 50 mg, 100 mg (3)CONTRAINDICATIONSAdministration of sildenafil tablets to patients using nitric oxide donors, such as organic nitrates or organic nitrites in any form. Sildenafil tablets was shown to potentiate the hypotensive effect of nitrates (4.1, 7.1, 12.2)Known hypersensitivity to sildenafil or any component of tablet (4.2)Administration with guanylate cyclase (GC) stimulators, such as riociguat (4.3)WARNINGS AND PRECAUTIONSPatients should not use sildenafil if sexual activity is inadvisable due to cardiovascular status (5.1)Patients should seek emergency treatment if an erection lasts >4 hours. Use sildenafil with caution in patients predisposed to priapism (5.2)Patients should stop sildenafil and seek medical care if a sudden loss of vision occurs in one or both eyes, which could be a sign of non arteritic anterior ischemic optic neuropathy (NAION). Sildenafil should be used with caution, and only when the anticipated benefits outweigh the risks, in patients with a history of NAION. Patients with a “crowded” optic disc may also be at an increased risk of NAION. (5.3)Patients should stop sildenafil and seek prompt medical attention in the event of sudden decrease or loss of hearing (5.4)Caution is advised when sildenafil is co-administered with alpha-blockers or anti-hypertensives. Concomitant use may lead to hypotension (5.5)Decreased blood pressure, syncope, and prolonged erection may occur at higher sildenafil exposures. In patients taking strong CYP inhibitors, such as ritonavir, sildenafil exposure is increased. Decrease in sildenafil dosage is recommended (2.4, 5.6)ADVERSE REACTIONSMost common sildenafil citrate tablets 50mg adverse reactions (> 2%) include headache, flushing, dyspepsia, abnormal vision, nasal congestion, back pain, myalgia, nausea, dizziness and rash (6.1)To report SUSPECTED ADVERSE REACTIONS, contact Aurobindo Pharma USA, Inc. at 1-866-850-2876 or FDA at 1-800-FDA-1088 or INTERACTIONSSildenafil can potentiate the hypotensive effects of nitrates, alpha blockers, and anti-hypertensives (4.1, 5.5, 7.1, 7.2, 7.3, 12.2)With concomitant use of alpha blockers, initiate sildenafil at 25 mg dose (2.3)CYP3A4 inhibitors (e.g., ritonavir, ketoconazole, itraconazole, erythromycin): Increase sildenafil exposure (2.4, 7.4, 12.3)Erythromycin or strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, saquinavir): Consider a starting dose of 25 mg (2.4, 7.4)Ritonavir: Do not exceed a maximum single dose of 25 mg in a 48 hour period (2.4, 5.6)USE IN SPECIFIC POPULATIONSSee 17 for PATIENT COUNSELING INFORMATION and FDA-approved patient labeling.Revised: 5/2023 Sildenafil is a phosphodiesterase-5 (PDE5) inhibitor indicated for the treatment of erectile dysfunction (ED) (1) For most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity.
8.6 Renal Impairment
Dosage forms
Levitra Generic
However, sildenafil tablets may be taken anywhere from 30 minutes to 4 hours before sexual activity (2.1) Based on effectiveness and toleration, may increase to a maximum of 100 mg or decrease to 25 mg (2.1) Maximum recommended dosing frequency is once per day (2.1) Tablets: 25 mg, 50 mg, 100 mg (3) Administration of sildenafil tablets to patients using nitric oxide donors, such as organic nitrates or organic nitrites in any form. Sildenafil tablets was shown to potentiate the hypotensive effect of nitrates (4.1, 7.1, 12.2) Known hypersensitivity to sildenafil or any component of tablet (4.2) Administration with guanylate cyclase (GC) stimulators, such as riociguat (4.3) Patients should not use sildenafil if sexual activity is inadvisable due to cardiovascular status (5.1) Patients should seek emergency treatment if an erection lasts >4 hours.
Data availability
Use sildenafil with caution in patients predisposed to priapism (5.2) Patients should stop sildenafil and seek medical care if a sudden loss of vision occurs in one or both eyes, which could be a sign of non arteritic anterior ischemic optic neuropathy (NAION).
- Sildenafil white is sometimes called the "blue pill" in popular culture.
- It remains one of the most prescribed medications for ED worldwide.
- Some individuals purchase sildenafil white without a prescription, which can be risky.
- Derived from a scientific discovery initially aimed at heart treatment.
- Viagra was the first brand to market sildenafil for ED.
- The medication can cause side effects like dizziness and upset stomach.
- Elderly patients should be cautious due to increased risk of side effects.
- Regular medical check-ups are recommended for long-term sildenafil users.
- Lifestyle changes, such as exercise and diet, can enhance treatment results.
- The medication is typically taken on an empty stomach for quicker effect.
- Research continues into new formulations and delivery methods for sildenafil
Patients should stop sildenafil and seek prompt medical attention in the event of sudden decrease or loss of hearing (5.4) Caution is advised when sildenafil is co-administered with alpha-blockers or anti-hypertensives. Concomitant use may lead to hypotension (5.5) Decreased blood pressure, syncope, and prolonged erection may occur at higher sildenafil exposures. Decrease in sildenafil dosage is recommended (2.4, 5.6) Most common adverse reactions (> 2%) include headache, flushing, dyspepsia, abnormal vision, nasal congestion, back pain, myalgia, nausea, dizziness and rash (6.1) Sildenafil can potentiate the hypotensive effects of nitrates, alpha blockers, and anti-hypertensives (4.1, 5.5, 7.1, 7.2, 7.3, 12.2) With concomitant use of alpha blockers, initiate sildenafil at 25 mg dose (2.3) CYP3A4 inhibitors (e.g., ritonavir, ketoconazole, itraconazole, erythromycin): Increase sildenafil exposure (2.4, 7.4, 12.3) Erythromycin or strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, saquinavir): Consider a starting dose of 25 mg (2.4, 7.4) Ritonavir: Do not exceed a maximum single dose of 25 mg in a 48 hour period (2.4, 5.6) See 17 for PATIENT COUNSELING INFORMATION and FDA-approved patient labeling.
- The term 'sildenafil white' often refers to unbranded, generic pills.
- It may be available online through various pharmacies and vendors.
- Users should verify the legitimacy of sildenafil sources to avoid fake products.
- This medication is not suitable for individuals with certain heart conditions.
- Sildenafil white is sometimes used recreationally for its euphoric effects.
- It may interact with certain antibiotics and antifungals, altering effectiveness.
- Patients should inform their doctor of all medications before use.
- The medication is not an aphrodisiac; it only facilitates erectile response.
- Overuse or misuse of sildenafil white can lead to serious health risks.
- The recommended maximum frequency is once per day unless advised otherwise.
- Consultation with a healthcare professional is essential prior to use.
Table of Contents FULL PRESCRIBING INFORMATION: CONTENTS*1 INDICATIONS AND USAGE2 DOSAGE AND ADMINISTRATION2.1 Dosage Information2.2 Use with Food2.3 Dosage Adjustments in Specific Situations2.4 Dosage Adjustments Due to Drug Interactions2.5 Dosage Adjustments in Special Populations3 DOSAGE FORMS AND STRENGTHS4 CONTRAINDICATIONS4.1 Nitrates4.2 Hypersensitivity Reactions4.3 Concomitant Guanylate Cyclase (GC) Stimulators5 WARNINGS AND PRECAUTIONS5.1 Cardiovascular5.2 Prolonged Erection and Priapism5.3 Effects on the Eye5.4 Hearing Loss5.5 Hypotension when Co-administered with Alpha-blockers or Anti-hypertensives5.6 Adverse Reactions with the Concomitant Use of Ritonavir5.7 Combination with other PDE5 Inhibitors or Other Erectile Dysfunction Therapies5.8 Effects on Bleeding5.9 Counseling Patients About Sexually Transmitted Diseases6 ADVERSE REACTIONS6.1 Clinical Trials Experience6.2 Postmarketing Experience7 DRUG INTERACTIONS7.1 Nitrates7.2 Alpha-blockers7.3 Amlodipine7.4 Ritonavir and Other CYP3A4 Inhibitors7.5 Alcohol8 USE IN SPECIFIC POPULATIONS8.1 Pregnancy8.2 Lactation8.4 Pediatric Use8.5 Geriatric Use8.6 Renal Impairment8.7 Hepatic Impairment10 OVERDOSAGE11 DESCRIPTION12 CLINICAL PHARMACOLOGY12.1 Mechanism of Action12.2 Pharmacodynamics12.3 Pharmacokinetics13 NONCLINICAL TOXICOLOGY13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility14 CLINICAL STUDIES16 HOW SUPPLIED/STORAGE AND HANDLING17 PATIENT COUNSELING INFORMATION*Sections or subsections omitted from the full prescribing information are not listed. 2 DOSAGE AND ADMINISTRATION 2.1 Dosage InformationFor most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. However, sildenafil tablets may be taken anywhere from 30 minutes to 4 hours before sexual activity. The maximum recommended dosing frequency is once per day.Based on effectiveness and toleration, the dose may be increased to a maximum recommended dose of 100 mg or decreased to 25 mg.2.3 Dosage Adjustments in Specific SituationsSildenafil tablets was shown to potentiate the hypotensive effects of nitrates and its administration in patients who use nitric oxide donors such as organic nitrates or organic nitrites in any form is therefore contraindicated [see Contraindications (4.1), Drug Interactions (7.1), and Clinical Pharmacology (12.2)].When sildenafil tablets are co-administered with an alpha-blocker, patients should be stable on alpha-blocker therapy prior to initiating sildenafil tablets treatment and sildenafil tablets should be initiated at 25 mg [see Warnings and Precautions (5.5), Drug Interactions (7.2), and Clinical Pharmacology (12.2)].2.4 Dosage Adjustments Due to Drug InteractionsRitonavirThe recommended dose for ritonavir-treated patients is 25 mg prior to sexual activity and the recommended maximum dose is 25 mg within a 48 hour period because concomitant administration increased the blood levels of sildenafil by 11-fold [see Warnings and Precautions (5.6), Drug Interactions (7.4), and Clinical Pharmacology (12.3)].CYP3A4 InhibitorsConsider a starting dose of 25 mg in patients treated with strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, or saquinavir) or erythromycin.