Understanding Sildenafil Citrate
Viagra is a medication used to treat erectile dysfunction by improving blood flow to the penis.
- Sildenafil can enhance the effects of other blood pressure medications.
- The drug’s safety profile is well-studied with many clinical trials.
- Cardiovascular health is an important consideration when taking sildenafil.
- Long-term use requires monitoring for adverse reactions.
- Patient education helps reduce risks and optimize dosage.
- Generic sildenafil offers a cost-effective alternative to branded Viagra.
- Regular health assessments can ensure safe usage.
The drug is available in different dosages.
| Storage Condition | Details | Temperature Range | Light Exposure | Humidity |
|---|---|---|---|---|
| Preferred Storage | Cool, dry place | 15-30°C | Keep in original container | Avoid humidity |
| Keep away from light | Protect from direct sunlight | N/A | Yes | N/A |
| Out of reach of children | Safety precaution | N/A | N/A | N/A |
The appropriate dose depends on factors like age, kidney or liver problems, and other medications being taken. While generally considered safe, Viagra can cause side effects, including headaches and low blood pressure. It can also interact negatively with other medications like nitrates.
Dosing & Uses
PDE5 inhibitors, including sildenafil, may potentiate the hypotensive effects of vericiguat. Vigabatrin: (Major) Vigabatrin should not be used with phosphodiesterase inhibitors, which is associated with serious ophthalmic effects (e.g., retinopathy or glaucoma) unless the benefit of treatment clearly outweighs the risks. Vonoprazan; Amoxicillin; Clarithromycin: (Major) Coadministration of clarithromycin is not recommended in patients receiving sildenafil for pulmonary arterial hypertension (PAH). Voriconazole: (Major) Coadministration of voriconazole is not recommended in patients receiving sildenafil for pulmonary arterial hypertension (PAH). When sildenafil is used for erectile dysfunction, consider a starting dose of 25 mg for patients receiving voriconazole.
Revatio for Oral Suspension
Voxelotor: (Moderate) Monitor for an increase in sildenafil-related adverse reactions if coadministration with voxelotor is necessary; consider a starting dose of 25 mg of sildenafil when prescribed for erectile dysfunction. Zafirlukast: (Moderate) Concomitant use of zafirlukast with sildenafil may increase sildenafil exposure. In vitro studies suggest zafirlukast inhibits CYP3A (weak) and CYP2C9 (moderate top potent). LiQrev Oral Susp: 1mL, 10mgRevatio/Sildenafil/Sildenafil Citrate Intravenous Inj Sol: 0.8mg, 1mLRevatio/Sildenafil/Sildenafil Citrate Oral Pwd F/Recon: 1mL, 10mgRevatio/Sildenafil/Sildenafil Citrate/Viagra Oral Tab: 20mg, 25mg, 50mg, 100mg 100 mg/day PO for erectile dysfunction; 240 mg/day PO or 30 mg/day IV for pulmonary arterial hypertension. 100 mg/day PO for erectile dysfunction; 240 mg/day PO or 30 mg/day IV for pulmonary arterial hypertension.
Can I take Viagra by snorting it?
Weight 45 kg or more: 40 mg PO 3 times daily.Weight 21 to 44 kg: 20 mg PO 3 times daily. Weight 45 kg or more: 40 mg PO 3 times daily.Weight 21 to 44 kg: 20 mg PO 3 times daily.Weight 20 kg or less: 10 mg PO 3 times daily. Guidelines recommend 1 mg/kg/dose PO every 8 hours. Guidelines recommend 1 mg/kg/dose PO every 8 hours and 0.4 mg/kg IV as a loading dose followed by a continuous infusion of 0.067 mg/kg/hour. The physiologic mechanism of erection of the penis involves release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. Viagra is a brand-name oral tablet prescribed for erectile dysfunction (ED).
| Condition | Description | Recommended Dosage | Notes |
|---|---|---|---|
| Erectile Dysfunction (ED) | Difficulty achieving or maintaining an erection | 50 mg before activity | Can be adjusted based on response |
| Pulmonary Arterial Hypertension | High blood pressure in lungs | 20 mg three times daily | Prescribed under medical supervision |
| Off-label uses | Other potential uses | Varies | Use under healthcare provider guidance |
You’ll find key information about Viagra below.
- Sildenafil is available in most countries through prescription only.
- It is used worldwide, with varying approval statuses.
- FDA and EMA have rigorous testing standards for sildenafil.
- Using the drug responsibly can lead to successful treatment outcomes.
- Combining sildenafil with other medications requires medical supervision.
- Be aware of the potential for drug interactions with heart or blood pressure meds.
- Always consult a healthcare professional for personalized advice.
Drug class: phosphodiesterase type 5 (PDE5) inhibitor In several clinical studies, Viagra was effective in treating erectile dysfunction (ED). In these studies, males who used the drug had an improved ability to have and keep erections during sexual activity.
- Sildenafil binds to phosphodiesterase type 5 enzymes in tissues.
- It was initially developed by Pfizer.
- The drug’s patent expired in many countries, increasing generic availability.
- It can improve quality of life for men with ED and pulmonary hypertension.
- Discuss potential interactions and health conditions with your doctor.
- Usage guidelines differ for ED and pulmonary hypertension treatment.
- Follow the prescribed dose and avoid exceeding recommended limits.
To learn more about Viagra’s effectiveness, see the “Viagra uses” section.
- Sildenafil citrate is manufactured by several pharmaceutical companies.
- Its chemical formula is C22H30N6O4S.
- It has a half-life of approximately 4 hours in the body.
- The drug enhances nitric oxide activity in the corpus cavernosum.
- It’s important to follow prescribed dosing to avoid adverse effects.
- It is classified as a phosphodiesterase type 5 inhibitor.
- Sildenafil was initially researched for angina before ED use.
Use of the term “male” in this article refers to sex assigned at birth.
| Product | Dosage | Quantity + Bonus | Price | |
|---|---|---|---|---|
| Viagra Generic | 200mg | 90 + 6 Pills | 170.79€ 162.66€ | |
| Viagra Generic | 100mg | 20 Pills | 45.58€ 43.41€ | |
| Viagra Generic | 100mg | 180 + 8 Pills | 199.37€ 189.88€ | |
| Viagra Generic | 200mg | 20 Pills | 61.69€ 58.75€ | |
| Viagra Generic | 150mg | 120 + 8 Pills | 177.58€ 169.12€ | |
| Viagra Generic | 25mg | 30 + 4 Pills | 47.97€ 45.69€ | |
| Viagra Generic | 25mg | 20 Pills | 37.74€ 35.94€ | |
| Viagra Generic | 200mg | 270 + 10 Pills | 379.76€ 361.68€ | |
| Kamagra Polo | 100mg | 32 Pills | 125.88€ 119.89€ | |
| Viagra Generic | 50mg | 360 + 10 Pills | 225.33€ 214.60€ | |
| Viagra Generic | 200mg | 30 + 2 Pills | 83.07€ 79.11€ | |
| Viagra Generic | 200mg | 360 + 10 Pills | 481.98€ 459.03€ | |
| Kamagra Oral Jelly | 100mg | 21 Sachets | 95.92€ 91.35€ | |
| Kamagra Oral Jelly | 100mg | 30 + 5 Sachets | 136.20€ 129.71€ | |
| Kamagra Polo | 100mg | 84 + 4 Pills | 244.49€ 232.85€ |
Viagra typically starts to work between 30 and 60 minutes after you take a dose of the drug.
Related/similar drugs
Sildenafil concentrations sildenafil citrates at 24 hours post a single 100 mg oral dose average 2 ng/mL (compared to peak plasma concentrations of approximately 440 ng/mL). While similar pharmacokinetic parameters were observed in healthy volunteers and patients with erectile dysfunction, the average steady-state concentrations were 20% to 50% higher and Cmin levels doubled in patients with PAH compared to healthy volunteers. Affected cytochrome P450 isoenzymes: CYP3A4 and CYP2C9Sildenafil is metabolized principally by the hepatic cytochrome P450 (CYP) 3A4; CYP2C9 is also involved to a lesser degree. Dosage reductions are recommended for patients receiving potent cytochrome CYP3A4 inhibitors. Sildenafil is rapidly absorbed after oral administration, with a mean absolute bioavailability of about 41% (25% to 63%).
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Its pharmacokinetics are dose-proportional over the recommended dose range. Maximum observed plasma concentrations are reached within 30 to 120 minutes (median 60 minutes) of oral dosing in the fasted state. Oral Suspension (Liqrev):When sildenafil is taken with a high fat meal, the rate of absorption is reduced, with a mean delay in Tmax of 60 minutes and a mean reduction in Cmax of 53%; the extent of absorption (AUC) is increased by 11%.Oral tablets and oral powder for suspension (Revatio, Viagra):When sildenafil is taken with a high fat meal, the rate of absorption is reduced, with a mean delay in Tmax of 60 minutes and a mean reduction in Cmax of 29%. A 10 mg IV dose is predicted to provide a pharmacological effect of sildenafil and its N-desmethyl metabolite equivalent to that of a 20 mg PO dose. Limited data do not report a clear association with the use of sildenafil and major birth defects, miscarriage, or adverse maternal or fetal outcomes when sildenafil is used during pregnancy.
Administration Notes
No evidence of teratogenicity or embryofetal toxicity was observed in animal reproduction studies using sildenafil at doses 32- and 65-times the recommended human dose. There are risks to the mother and fetus from untreated pulmonary arterial hypertension. Limited clinical data preclude a clear determination of the risk of sildenafil to an infant during breast-feeding. Data from a case report describe the presence of sildenafil and its active metabolite in human milk. There is insufficient information on the effects of sildenafil on the breast-fed infant and no information on the effects of sildenafil on milk production. But Viagra itself doesn’t give you an erection. You’ll need to be sexually aroused in order for the drug to work.
What special dietary instructions should I follow?
Nitric oxide then activates the enzyme guanylate cyclase, which results in increased levels of cGMP. Cyclic guanosine monophosphate causes smooth muscle relaxation in the corpus cavernosum thereby allowing inflow of blood; the exact mechanism by which cGMP stimulates relaxation of smooth muscles has not been determined. PDE5 is responsible for degradation of cGMP in the corpus cavernosum. Sildenafil enhances the effect of NO by inhibiting PDE5 thereby raising concentrations of cGMP in the corpus cavernosum. Sildenafil has no direct relaxant effect on isolated human corpus cavernosum and, at recommended doses, has no effect in the absence of sexual stimulation.
What else should I know about sildenafil?
As reported by the manufacturer, the pharmacodynamic response to sildenafil was assessed in eight double-blind, placebo-controlled crossover studies of patients with either organic or psychogenic erectile dysfunction. In these studies sexual stimulation resulted in improved erections, as assessed by penile plethysmography, after sildenafil administration compared with placebo. Most studies evaluated the efficacy of sildenafil approximately 60 minutes post dose. The erectile response, sildenafil chewable tablets as determined by penile plethysmography, generally increased with increasing sildenafil dose and plasma concentration. The time course of effect was examined in one study.
Azole Antifungals
The effects of sildenafil were evident for up to 4 hours, but the response was diminished compared to 2 hours.In vitro studies show that sildenafil is selective for PDE5 and its effect is more potent on PDE5 than on other known phosphodiesterases. The approximately 4,000-fold selectivity for PDE5 versus PDE3 is important because PDE3 is involved in control of cardiac contractility. Sildenafil can also inhibit PDE5 present in esophageal smooth muscle, lung tissue, and brain tissue. Inhibition of PDE5 in lung tissue results in relaxation of pulmonary vascular smooth muscle and subsequently pulmonary vasodilation, thereby making sildenafil an effective agent in treating pulmonary hypertension. Inhibition of PDE5 present in esophageal smooth muscle can cause a marked inhibition of esophageal motility as well as a reduction in lower esophageal sphincter (LES) tone. Viagra keeps working in your body for up to 5 hours.
| Patient Group | Starting Dose | Maximum Dose | Frequency | Notes |
|---|---|---|---|---|
| Adult Men with ED | 50 mg | 100 mg | Once per day, 1 hour before sex | Adjust based on efficacy and side effects |
| Patients with Liver Impairment | 25 mg | 50 mg | Once daily | Lower doses recommended |
| Elderly Patients | 25-50 mg | 100 mg | As needed | Monitor for side effects |
This means that if you’re aroused, you should still be able to get an erection up to 4 hours after taking a dose of Viagra.
2. Upsides
These effects may be beneficial in certain motor disorders involving the esophagus such as diffuse spasm, nutcracker esophagus, and hypertensive LES. However, the reduction in LES tone can worsen the symptoms of gastroesophageal reflux disease (GERD). Sildenafil is one-tenth as potent for PDE6, an enzyme found in the retina, as it is for PDE5; this lower selectivity is thought to be the basis for abnormalities related to color vision observed with higher doses or plasma concentrations of the drug. The mean steady state volume of distribution (Vss) is 105 L, indicating widespread tissue distribution. Sildenafil and its major circulating N-desmethyl metabolite are both approximately 96% bound to plasma proteins.
Brand Names
Protein binding is independent of total drug concentrations. Based upon measurements of sildenafil in semen of healthy volunteers 90 minutes after dosing, less than 0.001% of the administered dose may appear in the semen of patients. Sildenafil is predominantly metabolized by hepatic cytochrome P450 (CYP) enzymes. One active metabolite with properties similar to the parent drug has been identified and is formed by N-desmethylation of sildenafil. This metabolite has a PDE selectivity profile similar to sildenafil and an in vitro potency for PDE5 approximately 50% of the parent drug.
What can I do to make Viagra work faster?
Plasma concentrations of this metabolite are approximately 40% of those seen for sildenafil and accounts for about 20% of the pharmacologic effects of sildenafil. However, the ratio of the metabolite to sildenafil is higher in patients with pulmonary arterial hypertension (PAH). The metabolite is further metabolized to inactive compounds. Sildenafil is excreted as metabolites primarily in the feces (approximately 80% of administered oral dose) and to a lesser extent in the urine (approximately 13% of the administered oral dose). Both sildenafil and its active metabolite have terminal half-lives of about 4 hours.