12 CLINICAL PHARMACOLOGY
It is therefore recommended not to exceed a maximum single dose of 25 mg of sildenafil in a 48 hour period [see Dosage and Administration (2.4), Warnings and Precautions (5.6), Clinical Pharmacology (12.3)].Co-administration of erythromycin, a moderate CYP3A4 inhibitor, resulted in a 160% and 182% increases in sildenafil Cmax and AUC, respectively.
Uses of Sildenafil
What should I tell my healthcare provider before taking sildenafil?
Co-administration of saquinavir, a strong CYP3A4 inhibitor, resulted in 140% and 210% increases in sildenafil Cmax and AUC, respectively. Stronger CYP3A4 inhibitors such as ketoconazole or itraconazole could be expected to have greater effects than seen with saquinavir.
| Product | Dosage | Quantity + Bonus | Price | |
|---|---|---|---|---|
| Viagra Generic | 200mg | 60 + 4 Pills | 125.19€ 119.23€ | |
| Viagra Generic | 25mg | 360 + 10 Pills | 213.68€ 203.50€ | |
| Viagra Generic | 25mg | 10 Pills | 25.19€ 23.99€ | |
| Viagra Generic | 25mg | 20 Pills | 37.74€ 35.94€ | |
| Kamagra | 100mg | 360 + 6 Pills | 839.95€ 799.95€ | |
| Viagra Generic | 50mg | 360 + 10 Pills | 225.33€ 214.60€ | |
| Viagra Generic | 150mg | 90 + 6 Pills | 147.18€ 140.17€ | |
| Viagra Generic | 25mg | 90 + 6 Pills | 105.03€ 100.03€ | |
| Viagra Generic | 100mg | 10 Pills | 28.91€ 27.53€ | |
| Viagra Generic | 150mg | 30 + 2 Pills | 72.32€ 68.88€ | |
| Kamagra Polo | 100mg | 84 + 4 Pills | 244.49€ 232.85€ | |
| Viagra Generic | 50mg | 90 + 6 Pills | 107.37€ 102.26€ | |
| Viagra Generic | 100mg | 90 + 6 Pills | 129.02€ 122.88€ | |
| Viagra Generic | 200mg | 20 Pills | 61.69€ 58.75€ | |
| Kamagra Polo | 100mg | 60 + 4 Pills | 189.39€ 180.37€ | |
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A starting dose of 25 mg of sildenafil should be considered in patients taking erythromycin or strong CYP3A4 inhibitors (such as saquinavir, ketoconazole, itraconazole) [see Dosage and Administration (2.4), Clinical Pharmacology (12.3)].7.5 AlcoholIn a drug-drug interaction study sildenafil 50 mg given with alcohol 0.5 g/kg in which mean maximum blood alcohol levels of 0.08% was achieved, sildenafil did not potentiate the hypotensive effect of alcohol in healthy volunteers [see Clinical Pharmacology (12.2)]. When sildenafil 100 mg was co-administered with amlodipine (5 mg or 10 mg) to hypertensive patients, the mean additional reduction on supine blood pressure was 8 mmHg systolic and 7 mmHg diastolic [see Warnings and Precautions (5.5), Clinical Pharmacology (12.2)]. 8 USE IN SPECIFIC POPULATIONS 8.1 PregnancyRisk SummarySildenafil is not indicated for use in females.There are no data with the use of sildenafil in pregnant women to inform any drug-associated risks for adverse developmental outcomes. Animal reproduction studies conducted with sildenafil did not show adverse developmental outcomes when administered during organogenesis in rats and rabbits at oral doses up to 16 and 32 times, respectively, the maximum recommended human dose (MRHD) of 100 mg/day on a mg/m2 basis (see Data).DataAnimal DataNo evidence of teratogenicity, embryotoxicity or fetotoxicity was observed in rats and rabbits which received oral doses up to 200 mg/kg/day during organogenesis. These doses represent, respectively, about 16 and 32 times the MRHD on a mg/m2 basis in a 50 kg subject. In the rat pre- and postnatal development study, the no observed adverse effect dose was 30 mg/kg/day given for 36 days, about 2 times the MRHD on a mg/m2 basis in a 50 kg subject.8.2 LactationRisk SummarySildenafil is not indicated for use in females.Limited data indicate that sildenafil and its active metabolite are present in human milk. There is no information on the effects on the breastfed child, or the effects on milk production.8.4 Pediatric UseSildenafil is not indicated for use in pediatric patients.
Sildenafil Cautionary Labels
No evidence of teratogenicity, embryotoxicity or fetotoxicity was observed in rats and rabbits which received oral doses up to 200 mg/kg/day during organogenesis. In the rat pre- and postnatal development study, the no observed adverse effect dose was 30 mg/kg/day given for 36 days, about 2 times the MRHD on a mg/m2 basis in a 50 kg subject. Limited data indicate that sildenafil and its active metabolite are present in human milk. There is no information on the effects on the breastfed child, or the effects on milk production. No dose adjustment is required for mild (CLcr=50 to 80 sildenafil uk price mL/min) and moderate (CLcr = 30 to 49 mL/min) renal impairment.
Is it OK to take 100 mg of Teva sildenafil?
A starting dose of 25 mg should be considered in patients with severe renal impairment [see Dosage and Administration (2.5) and Clinical Pharmacology (12.3)]. 10 OVERDOSAGE In studies with healthy volunteers of single doses up to 800 mg, adverse reactions 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. In studies with healthy volunteers of single doses up to 800 mg, adverse reactions were similar to those seen at lower doses but incidence rates and severities were increased. Each tablet contains sildenafil citrate USP equivalent to 25 mg, 50 mg and 100 mg of sildenafil. Sildenafil tablets USP, 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). Safety and effectiveness have not been established in pediatric patients.8.5 Geriatric UseHealthy elderly volunteers (65 years or over) had a reduced clearance of sildenafil resulting in approximately 84% and 107% higher plasma AUC values of sildenafil and its active N-desmethyl metabolite, respectively, compared to those seen in healthy young volunteers (18 to 45 years) [see Clinical Pharmacology (12.3)]. Due to age-differences in plasma protein binding, the corresponding increase in the AUC of free (unbound) sildenafil and its active N-desmethyl metabolite were 45% and 57%, respectively [see Clinical Pharmacology (12.3)].Of the total number of subjects in clinical studies of sildenafil, 18% were 65 years and older, while 2% were 75 years and older.
7.4 Ritonavir and Other CYP3A4 Inhibitors
It is therefore recommended not to exceed a maximum single dose of 25 mg of sildenafil in a 48 hour period [see Dosage and Administration (2.4), Warnings and Precautions (5.6), Clinical Pharmacology (12.3)].Co-administration of erythromycin, a moderate CYP3A4 inhibitor, resulted in a 160% and 182% increases in sildenafil Cmax and AUC, respectively. Co-administration of saquinavir, a strong CYP3A4 inhibitor, resulted in 140% and 210% increases in sildenafil Cmax and AUC, respectively. Stronger CYP3A4 inhibitors such as ketoconazole or itraconazole could be expected to have greater effects than seen with saquinavir. A starting dose of 25 mg of sildenafil should be considered in patients taking erythromycin or strong CYP3A4 inhibitors (such as saquinavir, ketoconazole, itraconazole) [see Dosage and Administration (2.4), Clinical Pharmacology (12.3)].7.5 AlcoholIn a drug-drug interaction study sildenafil 50 mg given with alcohol 0.5 g/kg in which mean maximum blood alcohol levels of 0.08% was achieved, sildenafil did not potentiate the hypotensive effect of alcohol in healthy volunteers [see Clinical Pharmacology (12.2)]. When sildenafil 100 mg was co-administered with amlodipine (5 mg or 10 mg) to hypertensive patients, the mean additional reduction on supine blood pressure was 8 mmHg systolic and 7 mmHg diastolic [see Warnings and Precautions (5.5), Clinical Pharmacology (12.2)].
Drugs you should not use with sildenafil
8 USE IN SPECIFIC POPULATIONS 8.1 PregnancyRisk SummarySildenafil is not indicated for use in females.There are no data with the use of sildenafil in pregnant women to inform any drug-associated risks for adverse developmental outcomes. Animal reproduction studies conducted with sildenafil did not show adverse developmental outcomes when administered during organogenesis in rats and rabbits at oral doses up to 16 and 32 times, respectively, the maximum recommended human dose (MRHD) of 100 mg/day on a mg/m2 basis (see Data).DataAnimal DataNo evidence of teratogenicity, embryotoxicity or fetotoxicity was observed in rats and rabbits which received oral doses up to 200 mg/kg/day during organogenesis. These doses represent, respectively, about 16 and 32 times the MRHD on a mg/m2 basis in a 50 kg subject. In the rat pre- and postnatal development study, the no observed adverse effect dose was 30 mg/kg/day given for 36 days, about 2 times the MRHD on a mg/m2 basis in a 50 kg subject.8.2 LactationRisk SummarySildenafil is not indicated for use in females.Limited data indicate that sildenafil and its active metabolite are present in human milk. There is no information on the effects on the breastfed child, or the effects on milk production.8.4 Pediatric UseSildenafil is not indicated for use in pediatric patients. No overall differences in safety or efficacy were observed between older (> 65 years of age) and younger (< 65 years of age) subjects.However, since higher plasma levels may increase the incidence of adverse reactions, a starting dose of 25 mg should be considered in older subjects due to the higher systemic exposure [see Dosage and Administration (2.5)].8.6 Renal ImpairmentNo dose adjustment is required for mild (CLcr=50 to 80 mL/min) and moderate (CLcr = 30 to 49 mL/min) renal impairment.
8.7 Patients with Renal Impairment
Sildenafil tablets, USP are formulated as white to off-white, diamond shaped, biconvex, film-coated tablets for oral administration. 12 CLINICAL PHARMACOLOGY 12.1 Mechanism of ActionThe 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 enhances the effect of 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.Binding CharacteristicsStudies in vitro have shown that sildenafil is selective for PDE5.
What is sildenafil used for?
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). Sildenafil is approximately 4,000-fold more selective for PDE5 compared to PDE3. 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 [see Clinical Pharmacology (12.2)].In addition to human corpus cavernosum smooth muscle, PDE5 is also found in other tissues including platelets, vascular and visceral smooth muscle, and skeletal muscle, brain, heart, liver, kidney, lung, pancreas, prostate, bladder, testis, and seminal vesicle. In volunteers with severe renal impairment (Clcr<30 mL/min), sildenafil clearance was reduced, resulting in higher plasma exposure of sildenafil (~2 fold), approximately doubling of Cmax and AUC. A starting dose of 25 mg should be considered in patients with severe renal impairment [see Dosage and Administration (2.5) and Clinical Pharmacology (12.3)].8.7 Hepatic ImpairmentIn volunteers with hepatic impairment (Child-Pugh Class A and B), sildenafil clearance was reduced, resulting in higher plasma exposure of sildenafil (47% for Cmax and 85% for AUC). The pharmacokinetics of sildenafil in patients with severely impaired hepatic function (Child-Pugh Class C) have not been studied.
- Sildenafil white was first approved by the FDA in 1998.
- It is marketed under various brand and generic names worldwide.
- The drug belongs to a class called phosphodiesterase inhibitors.
- It is effective for many men with both physical and psychological ED.
- Sildenafil white may also help treat pulmonary arterial hypertension.
- Some users report experiencing visual disturbances after taking it.
- The medication’s effects last approximately 4 to 6 hours.
- It is advisable to avoid alcohol when taking sildenafil white.
- Consumers should check for potential drug allergies before use.
- The pill's color and shape can vary depending on the manufacturer.
- Always consult a healthcare provider for appropriate use and dosing.
A starting dose of 25 mg should be considered in patients with any degree of hepatic impairment [see Dosage and Administration (2.5) and Clinical Pharmacology (12.3)]. Sildenafil is not indicated for use in females. There are no data with the use of sildenafil in pregnant women to inform any drug-associated risks for adverse developmental outcomes. Animal reproduction studies conducted with sildenafil did not show adverse developmental outcomes when administered during organogenesis in rats and rabbits at oral doses up to 16 and 32 times, respectively, the maximum recommended human dose (MRHD) of 100 mg/day on a mg/m2 basis (see Data).
- Sildenafil white is a common name for the generic version of Viagra.
- It is used to treat erectile dysfunction in men.
- Sildenafil white is known for its rapid onset of action.
- The medication works by enhancing blood flow to the penis.
- It is typically taken about 30 to 60 minutes before sexual activity.
- Sildenafil white is available in various doses, usually 25mg, 50mg, and 100mg.
- The drug should not be used with nitrate medications to avoid dangerous interactions.
- Common side effects include headache, flushing, and nasal congestion.
- It is important to follow dosage instructions provided by a healthcare provider.
- Sildenafil white can cause low blood pressure in some users.
- Store sildenafil white in a cool, dry place, away from direct sunlight.
No evidence of teratogenicity, embryotoxicity or fetotoxicity was observed in rats and rabbits which received oral doses up to 200 mg/kg/day during organogenesis. In the rat pre- and postnatal development study, the no observed adverse effect dose was 30 mg/kg/day given for 36 days, about 2 times the MRHD on a mg/m2 basis in a 50 kg subject. Limited data indicate that sildenafil and its active metabolite are present in human milk. There is no information on the effects on the breastfed child, or the effects on milk production. No dose adjustment is required for mild (CLcr=50 to 80 sildenafil uk price mL/min) and moderate (CLcr = 30 to 49 mL/min) renal impairment. A starting dose of 25 mg should be considered in patients with severe renal impairment [see Dosage and Administration (2.5) and Clinical Pharmacology (12.3)]. 10 OVERDOSAGE In studies with healthy volunteers of single doses up to 800 mg, adverse reactions 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. In studies with healthy volunteers of single doses up to 800 mg, adverse reactions were similar to those seen at lower doses but incidence rates and severities were increased. Each tablet contains sildenafil citrate USP equivalent to 25 mg, 50 mg and 100 mg of sildenafil. Sildenafil tablets USP, 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 tablets, USP are formulated as white to off-white, diamond shaped, biconvex, film-coated tablets for oral administration.
12.1 Mechanism of Action
Safety and effectiveness have not been established in pediatric patients.8.5 Geriatric UseHealthy elderly volunteers (65 years or over) had a reduced clearance of sildenafil resulting in approximately 84% and 107% higher plasma AUC values of sildenafil and its active N-desmethyl metabolite, respectively, compared to those seen in healthy young volunteers (18 to 45 years) [see Clinical Pharmacology (12.3)]. Due to age-differences in plasma protein binding, the corresponding increase in the AUC of free (unbound) sildenafil and its active N-desmethyl metabolite were 45% and 57%, respectively [see Clinical Pharmacology (12.3)].Of the total number of subjects in clinical studies of sildenafil, 18% were 65 years and older, while 2% were 75 years and older. No overall differences in safety or efficacy were observed between older (> 65 years of age) and younger (< 65 years of age) subjects.However, since higher plasma levels may increase the incidence of adverse reactions, a starting dose of 25 mg should be considered in older subjects due to the higher systemic exposure [see Dosage and Administration (2.5)].8.6 Renal ImpairmentNo dose adjustment is required for mild (CLcr=50 to 80 mL/min) and moderate (CLcr = 30 to 49 mL/min) renal impairment. In volunteers with severe renal impairment (Clcr<30 mL/min), sildenafil clearance was reduced, resulting in higher plasma exposure of sildenafil (~2 fold), approximately doubling of Cmax and AUC. A starting dose of 25 mg should be considered in patients with severe renal impairment [see Dosage and Administration (2.5) and Clinical Pharmacology (12.3)].8.7 Hepatic ImpairmentIn volunteers with hepatic impairment (Child-Pugh Class A and B), sildenafil clearance was reduced, resulting in higher plasma exposure of sildenafil (47% for Cmax and 85% for AUC).
Raynaud's phenomenon
The pharmacokinetics of sildenafil in patients with severely impaired hepatic function (Child-Pugh Class C) have not been studied. A starting dose of 25 mg should be considered in patients with any degree of hepatic impairment [see Dosage and Administration (2.5) and Clinical Pharmacology (12.3)]. Sildenafil is not indicated for use in females. There are no data with the use of sildenafil in pregnant women to inform any drug-associated risks for adverse developmental outcomes. Animal reproduction studies conducted with sildenafil did not show adverse developmental outcomes when administered during organogenesis in rats and rabbits at oral doses up to 16 and 32 times, respectively, the maximum recommended human dose (MRHD) of 100 mg/day on a mg/m2 basis (see Data). 12 CLINICAL PHARMACOLOGY 12.1 Mechanism of ActionThe 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 enhances the effect of NO by inhibiting phosphodiesterase type 5 (PDE5), which is responsible for degradation of cGMP in the corpus cavernosum.
| Aspect | Details | Notes |
|---|---|---|
| Average Price (per tablet) | $2 - $5 depending on dosage and brand | Varies by region |
| Prescription Requirement | Required in most countries | Check local laws |
| Online Purchase | Available from licensed pharmacies | Ensure authenticity |
| Generic Options | Widely available, lower cost | Same active ingredient |
| Health Insurance Coverage | Often excludes over-the-counter drugs | Check policy |
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.Binding CharacteristicsStudies in vitro 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).
| Side Effect | Severity | Frequency | Comments |
|---|---|---|---|
| Headache | Common | Frequent | Usually mild |
| Flushing | Common | Frequent | Temporary, resolves quickly |
| Dyspepsia | Mild to moderate | Occasionally | Indigestion or upset stomach |
| Vision Changes | Rare | Infrequent | Bluish tint, increased light sensitivity |
| Priapism | Severe | Rare | Medical emergency |
Sildenafil is approximately 4,000-fold more selective for PDE5 compared to PDE3. 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 [see Clinical Pharmacology (12.2)].In addition to human corpus cavernosum smooth muscle, PDE5 is also found in other tissues including platelets, vascular and visceral smooth muscle, and skeletal muscle, brain, heart, liver, kidney, lung, pancreas, prostate, bladder, testis, and seminal vesicle.
Additional information
The inhibition of PDE5 in some of these tissues by sildenafil may be the basis for the enhanced platelet antiaggregatory activity of NO observed in vitro, an inhibition of platelet thrombus formation in vivo and peripheral arterial-venous dilatation in vivo.12.2 PharmacodynamicsEffects of Sildenafil on Erectile Response: In eight double-blind, placebo-controlled crossover studies of patients with either organic or psychogenic erectile dysfunction, sexual stimulation resulted in improved erections, as assessed by an objective measurement of hardness and duration of erections (RigiScan®), after sildenafil administration compared with placebo. Most studies assessed the efficacy of sildenafil approximately 60 minutes post dose. The erectile response, as assessed by RigiScan®, generally increased with increasing sildenafil dose and plasma concentration. The time course of effect was examined in one study, showing an effect for up to 4 hours but the response was diminished compared to 2 hours.Effects of Sildenafil on Blood Pressure: Single oral doses of sildenafil (100 mg) administered to healthy volunteers produced decreases in sitting blood pressure (mean maximum decrease in systolic/diastolic blood pressure of 8.3/5.3 mmHg).
Sildenafil (Viagra)
The inhibition of PDE5 in some of these tissues by sildenafil may be the basis for the enhanced platelet antiaggregatory activity of NO observed in vitro, an inhibition of platelet thrombus formation in vivo and peripheral arterial-venous dilatation in vivo.12.2 PharmacodynamicsEffects of Sildenafil on Erectile Response: In eight double-blind, placebo-controlled crossover studies of patients with either organic or psychogenic erectile dysfunction, sexual stimulation resulted in improved erections, as assessed by an objective measurement of hardness and duration of erections (RigiScan®), after sildenafil administration compared with placebo. Most studies assessed the efficacy of sildenafil approximately 60 minutes post dose. The erectile response, as assessed by RigiScan®, generally increased with increasing sildenafil dose and plasma concentration.
| Country/Region | Regulatory Body | Status of Sildenafil White | Notes |
|---|---|---|---|
| United States | FDA | Approved for ED and pulmonary hypertension | Prescription-only |
| European Union | EMA | Approved, similar indications | Prescription required |
| Canada | Health Canada | Approved with similar uses | Prescription needed |
| Australia | TGA | Approved for ED and pulmonary use | Prescription-only |
| India | CDSCO | Approved, widely available | Over-the-counter in some states |
The time course of effect was examined in one study, showing an effect for up to 4 hours but the response was diminished compared to 2 hours.Effects of Sildenafil on Blood Pressure: Single oral doses of sildenafil (100 mg) administered to healthy volunteers produced decreases in sitting blood pressure (mean maximum decrease in systolic/diastolic blood pressure of 8.3/5.3 mmHg).
- Sildenafil white is often sold as small, round, white tablets.
- It is available in various formulations, including sublingual and capsules.
- The drug increases cGMP levels, leading to smooth muscle relaxation.
- Generic sildenafil is usually cheaper than brand-name Viagra.
- Erectile dysfunction can be caused by physical or mental health issues.
- Misusing sildenafil white can result in priapism, a painful erection lasting hours.
- Some formulations come with flavoring to improve taste.
- Patient education about correct use is key to safety and effectiveness.
- Sildenafil white does not protect against sexually transmitted infections.
- It is important to avoid taking more than the recommended dose.
- Long-term safety data is still being studied, but generally considered safe when used properly.