Sildenafil Citrate Uses

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• Sildenafil Citrate indications
• Uses of Sildenafil Citrate in details
• Sildenafil Citrate description
• Sildenafil Citrate dosage
• Sildenafil Citrate interactions
• Sildenafil Citrate side effects
• Sildenafil Citrate contraindications

What is Sildenafil Citrate?

Sildenafil Citrate is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil Citrate belongs to a group of medicines called phosphodiesterase 5 (PDE5) inhibitors. These medicines prevent an enzyme called phosphodiesterase type-5 from working too quickly. The penis is one of the areas where this enzyme works.

Erectile dysfunction is a condition where the penis does not harden and expand when a man is sexually excited, or when he cannot keep an erection. When a man is sexually stimulated, his body's normal response is to increase blood flow to his penis to produce an erection. By controlling the enzyme, Sildenafil Citrate helps to maintain an erection after the penis is stroked. Without physical action to the penis, such as that occurring during sexual intercourse, Sildenafil Citrate will not work to cause an erection.

Sildenafil Citrate is also used in both men and women to treat the symptoms of pulmonary arterial hypertension. This is a type of high blood pressure that occurs between the heart and the lungs. When hypertension occurs in the lungs, the heart must work harder to pump enough blood through the lungs. Sildenafil Citrate works on the PDE5 enzyme in the lungs to relax the blood vessels. This will increase the supply of blood to the lungs and reduce the workload of the heart.

Sildenafil Citrate is available only with your doctor's prescription.

Sildenafil Citrate indications

Sildenafil Citrate Injection is indicated for the treatment of pulmonary arterial hypertension (WHO Group I) in adults to improve exercise ability and delay clinical worsening. The delay in clinical worsening was demonstrated when Sildenafil Citrate Injection was added to background epoprostenol therapy.

Studies establishing effectiveness were short-term (12 to 16 weeks), and included predominately patients with New York Heart Association (NYHA) Functional Class II-III symptoms and idiopathic etiology (71%) or associated with connective tissue disease (CTD) (25%).

How should I use Sildenafil Citrate?

Use Sildenafil Citrate suspension as directed by your doctor. Check the label on the medicine for exact dosing instructions.

• An extra patient leaflet with detailed instructions for use is available with Sildenafil Citrate suspension. Talk to your pharmacist if you have questions about this information.
• Take Sildenafil Citrate suspension by mouth with or without food. Take your doses 4 to 6 hours apart unless your doctor tells you otherwise.
• Shake well for at least 10 seconds before each use.
• Use the oral dosing syringe that comes with Sildenafil Citrate suspension to measure your dose. Ask your pharmacist for help if you are unsure of how to measure your dose.
• Do not mix Sildenafil Citrate suspension with other medicine or flavoring.
• Wash and dry the dosing syringe after each use.
• Take Sildenafil Citrate suspension on a regular schedule to get the most benefit from it. Take it at the same times each day.
• Continue to take Sildenafil Citrate suspension even if you feel well. Do not miss any doses.
• Do not suddenly stop taking Sildenafil Citrate suspension or change your dose without talking to your doctor.
• If you miss a dose of Sildenafil Citrate suspension, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use Sildenafil Citrate suspension.

Uses of Sildenafil Citrate in details

Use: Labeled Indications

Erectile dysfunction: Viagra: Treatment of erectile dysfunction.

Pulmonary arterial hypertension: Sildenafil Citrate: Treatment of pulmonary arterial hypertension (WHO group I; efficacy established predominately in patients with WHO/NYHA functional class II and III) in adults to improve exercise ability and delay clinical worsening.

Off Label Uses

High-altitude pulmonary edema

Based on the 2019 Wilderness Medical Society consensus guidelines for the prevention and treatment of acute altitude illness, Sildenafil Citrate is a recommended option for the prevention and treatment of high-altitude pulmonary edema (as an adjunct to descent, oxygen, or portable hyperbaric therapy). Supplemental oxygen and descent are the mainstays of treatment. For prevention, Sildenafil Citrate should only be considered for patients with a history of high-altitude pulmonary edema, especially multiple episodes.

Raynaud phenomenon

Data from a meta-analysis and small controlled trials support the use of Sildenafil Citrate for Raynaud phenomenon related to systemic sclerosis, demonstrating a decrease in the frequency and severity of attacks.

Sildenafil Citrate description

Each tablet contains Sildenafil Citrate equivalent to Sildenafil Citrate 50 mg and 100 mg.

Sildenafil Citrate dosage

Sildenafil Citrate Injection

Sildenafil Citrate Injection is for the continued treatment of patients with PAH who are currently prescribed oral Sildenafil Citrate and who are temporarily unable to take oral medication.

The recommended dose is 10 mg administered as an intravenous bolus injection three times a day. The dose of Sildenafil Citrate Injection does not need to be adjusted for body weight.

A 10 mg dose of Sildenafil Citrate Injection is predicted to provide pharmacological effect of Sildenafil Citrate and its N-desmethyl metabolite equivalent to that of a 20 mg oral dose.

Sildenafil Citrate interactions

See also:
What other drugs will affect Sildenafil Citrate?

When this drug applied simultaneously with:

- inhibitors of CYP3A4 (erythromycin, cimetidine) decreased clearance of Sildenafil Citrate, increasing the concentration of Sildenafil Citrate in plasma.

- indinavir, saquinavir, ritonavir increases the plasma C_max and AUC of Sildenafil Citrate, which is due to inhibition of CYP3A4 isoenzyme under the influence of indinavir, saquinavir, ritonavir.

One might expect that stronger inhibitors of isoenzyme CYP3A4, such as ketoconazole or itraconazole would increase the concentration of this medication in the blood plasma.

While the use with nitrates the hypotensive effect of nitrates increases.

There was described a case of rhabdomyolysis symptoms after a single oral dose of Sildenafil Citrate in patients receiving simvastatin.

Sildenafil Citrate side effects

See also:
What are the possible side effects of Sildenafil Citrate?

The following serious adverse events are discussed elsewhere in the labeling:

• Mortality with pediatric use
• Hypotension
• Vision loss
• Hearing loss
• Priapism
• Vaso-occlusive crisis

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.

Safety data of Sildenafil Citrate in adults were obtained from the 12-week, placebo-controlled clinical study (Study 1) and an open-label extension study in 277 Sildenafil Citrate-treated patients with PAH, WHO Group I.

The overall frequency of discontinuation in Sildenafil Citrate-treated patients on 20 mg three times a day was 3% and was the same for the placebo group.

In Study 1, the adverse reactions that were reported by at least 3% of Sildenafil Citrate-treated patients (20 mg three times a day) and were more frequent in Sildenafil Citrate-treated patients than in placebo-treated patients are shown in Table 1. Adverse reactions were generally transient and mild to moderate in nature.

At doses higher than the recommended 20 mg three times a day, there was a greater incidence of some adverse reactions including flushing, diarrhea, myalgia and visual disturbances. Visual disturbances were identified as mild and transient, and were predominately color-tinge to vision, but also increased sensitivity to light or blurred vision.

The incidence of retinal hemorrhage with Sildenafil Citrate 20 mg three times a day was 1.4% versus 0% placebo and for all Sildenafil Citrate doses studied was 1.9% versus 0% placebo. The incidence of eye hemorrhage at both 20 mg three times a day and at all doses studied was 1.4% for Sildenafil Citrate versus 1.4% for placebo. The patients experiencing these reactions had risk factors for hemorrhage including concurrent anticoagulant therapy.

In a placebo-controlled fixed dose titration study (Study 2) of Sildenafil Citrate (starting with recommended dose of 20 mg and increased to 40 mg and then 80 mg all three times a day) as an adjunct to intravenous epoprostenol in patients with PAH, the adverse reactions that were more frequent in the Sildenafil Citrate + epoprostenol group than in the epoprostenol group (greater than 6% difference) are shown in Table 2.

Sildenafil Citrate Injection

Sildenafil Citrate Injection was studied in a 66-patient, placebo-controlled study in patients with PAH at doses targeting plasma concentrations between 10 and 500 ng/mL (up to 8 times the exposure of the recommended dose). Adverse events with Sildenafil Citrate Injection were similar to those seen with oral tablets.

Postmarketing Experience

The following adverse reactions have been identified during post approval use of Sildenafil Citrate (marketed for both PAH and erectile dysfunction). Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Cardiovascular Events

In postmarketing experience with Sildenafil Citrate at doses indicated for erectile dysfunction, serious cardiovascular, cerebrovascular, and vascular events, including myocardial infarction, sudden cardiac death, ventricular arrhythmia, cerebrovascular hemorrhage, transient ischemic attack, hypertension, pulmonary hemorrhage, and subarachnoid and intracerebral hemorrhages have been reported in temporal association with the use of the drug. Most, but not all, of these patients had preexisting cardiovascular risk factors. Many of these events were reported to occur during or shortly after sexual activity, and a few were reported to occur shortly after the use of Sildenafil Citrate without sexual activity. Others were reported to have occurred hours to days after use concurrent with sexual activity. It is not possible to determine whether these events are related directly to Sildenafil Citrate, to sexual activity, to the patient’s underlying cardiovascular disease, or to a combination of these or other factors.

Nervous system

Seizure, seizure recurrence

Sildenafil Citrate contraindications

See also:
What is the most important information I should know about Sildenafil Citrate?

Hypersensitivity to the active substance or to any of the excipients.

Consistent with its known effects on the nitric oxide/cyclic guanosine monophosphate (cGMP) pathway, Sildenafil Citrate was shown to potentiate the hypotensive effects of nitrates, and its co-administration with nitric oxide donors (such as amyl nitrite) or nitrates in any form is therefore contraindicated. Agents for the treatment of erectile dysfunction, including Sildenafil Citrate, should not be used in men for whom sexual activity is inadvisable (eg, patients with severe cardiovascular disorders such as unstable angina or severe cardiac failure). Sildenafil Citrate is contraindicated in patients who have loss of vision in one eye because of non-arteritic anterior ischaemic optic neuropathy (NAION), regardless of whether this episode was in connection or not with previous PDE5 inhibitor exposure. The safety of Sildenafil Citrate has not been studied in the following sub-groups of patients and its use is therefore contraindicated: Severe hepatic impairment, hypotension (blood pressure <90/50 mmHg), recent history of stroke or myocardial infarction and known hereditary degenerative retinal disorders such as retinitis pigmentosa (a minority of these patients have genetic disorders of retinal phosphodiesterases).

Active ingredient matches for Sildenafil Citrate:

Sildenafil Citrate

References

1. PubChem. "sildenafil". https://pubchem.ncbi.nlm.nih.gov/com... (accessed September 17, 2018).
2. DrugBank. "sildenafil". http://www.drugbank.ca/drugs/DB00203 (accessed September 17, 2018).
3. MeSH. "Urological Agents". https://www.ncbi.nlm.nih.gov/mesh/68... (accessed September 17, 2018).

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Information checked by Dr. Sachin Kumar, MD Pharmacology