Sildaristo

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Medically reviewed

Marina Burgos

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Sildaristo

What is Sildaristo?

Sildaristo is a pharmaceutical medication developed for the treatment of erectile dysfunction in adult men. It belongs to a group of medicines known as phosphodiesterase type 5 (PDE5) inhibitors. The medication is designed to assist individuals who have difficulty achieving or maintaining an erection sufficient for sexual activity.

Active Ingredient and Mechanism

The primary active substance in Sildaristo is sildenafil. This compound works by influencing the body's physiological response to sexual stimulation. Under normal conditions, sexual arousal leads to the release of nitric oxide in the erectile tissue of the penis, which then activates an enzyme that produces cyclic guanosine monophosphate (cGMP). This chemical relaxes the smooth muscles and allows increased blood flow into the penis.

Sildenafil acts by protecting cGMP from being degraded by the PDE5 enzyme. By inhibiting this enzyme, Sildaristo helps maintain higher levels of cGMP, which supports the relaxation of blood vessels and facilitates a natural erectile response.

Functional Requirements

It is important to note that Sildaristo is not an aphrodisiac and does not automatically cause an erection. The medication requires the presence of natural sexual stimulation to be effective. The biochemical process it supports is dependent on the initial signals sent by the nervous system during arousal. Without such stimulation, the medication remains inactive in the body's vascular system.

Regulatory References

  1. EMA EPAR for Sildenafil (Viagra)
  2. NIH Pharmacokinetics Summary

What side effects are possible with Sildaristo?

Official Classification of Adverse Reactions

Adverse reactions associated with Sildaristo (Sildenafil) are formally classified by government regulatory authorities based on frequency and the body system affected. The most frequently documented adverse reaction is Headache, categorized as Very Common (1/10).

Common reactions (1/100 to < 1/10) typically reflect the medicine's vasodilatory effects, and include Flushing or hot flush, Dyspepsia (indigestion), Nasal congestion, and Visual disturbances such as color distortion or blurred vision. These effects are primarily documented within the Vascular, Nervous System, and Eye Disorders System Organ Classes.

Serious Adverse Events and Constraints

Rare adverse reactions (1/10,000 to < 1/1,000) documented in official labeling include critical events such as Myocardial infarction, Sudden cardiac death, and the potential for Priapism (a prolonged erection). Additionally, Non-arteritic anterior ischaemic optic neuropathy (NAION), a cause of sudden vision loss, has been reported in temporal association with PDE5 inhibitor use.

Safety-related restrictions strictly define conditions under which Sildaristo should not be used (contraindicated). These include individuals using any form of nitrates or nitric oxide donors, as well as patients with severe hepatic impairment, recent history of stroke or myocardial infarction, or resting hypotension (blood pressure < 90/50 mmHg). Caution is also specified for patients with an anatomical deformation of the penis or those with a predisposition to priapism, such as sickle cell anemia.

Overdose and Emergency Response

Overdose and when to seek help

The official regulatory documentation for Sildaristo (Sildenafil) describes overdose manifestations as an exaggeration of known adverse reactions, occurring with increased incidence and severity. In clinical studies, single doses up to 800 mg resulted in higher rates of common effects, including headache, flushing, dyspepsia, and abnormal vision. The overdose profile also includes severe outcomes like hypotension and syncope due to exaggerated pharmacological effects.

When to Seek Urgent Medical Attention

Immediate medical assistance must be sought if an erection persists longer than 4 hours (priapism). Regulatory labeling indicates this is a time-sensitive emergency that may lead to penile tissue damage and permanent loss of potency if it remains untreated. Urgent medical care is also mandated if a patient experiences sudden loss of vision or sudden decrease or loss of hearing, with instructions to immediately stop taking the product and contact emergency services.

Management and Constraints

Management of acute overexposure is restricted to symptomatic and supportive treatment. No specific pharmacological antidote is known. Regulatory authorities advise that renal dialysis is not expected to accelerate clearance because the active substance is highly bound to plasma proteins. It is also noted that patients with severe renal or hepatic impairment, as well as elderly patients, are documented to have increased systemic exposure, which is a factor relevant to overdosage risk.

Therapeutic Uses of Sildaristo

What Sildaristo Treats: Main Uses and Benefits

Sildaristo is used to help address symptoms related to two core therapeutic domains that involve supportive symptom management. This medication may assist with symptoms that interfere with daily functioning and those related to heightened physiological activity. It is applied in clinical settings that involve acute or unstable symptom patterns where short-term symptomatic assistance is needed to improve comfort and stability.


Therapeutic Domains and Symptom Relief

The medication is commonly used across conditions presenting with systemic or localized discomfort and those involving episodic or fluctuating manifestations. This addresses symptom clusters that may become intense or disruptive, supporting patients during difficult episodes.

It is often used when symptoms intensify and supportive relief is needed.

“The medication may assist with maintaining functional stability, providing supportive relief when symptoms interfere with routine activities.”


Quick Fact: Focus on Functional Strain
Sildaristo is considered relevant for easing symptoms that create noticeable functional strain and contribute to heightened physiological stress.

This contributes to improved day-to-day comfort during symptomatic periods and helps maintain a sense of stability when symptoms are more noticeable.

Regulatory References

  1. NIH MedlinePlus Drug Information on Sildenafil

Eligibility and Restrictions for Use

Sildaristo (sildenafil) is primarily indicated for treating erectile dysfunction in adult men and pulmonary arterial hypertension (PAH) in adults and some children. However, its use is not suitable for everyone and requires a thorough medical evaluation.

Contraindications (Who Should NOT Use Sildaristo)

The medicine is absolutely contraindicated in patients who:

  • Are taking nitrates (e.g., nitroglycerin, isosorbide mononitrate) or nitric oxide donors in any form. This combination can cause a dangerous and potentially fatal drop in blood pressure.
  • Are taking guanylate cyclase (GC) stimulators, such as riociguat, due to the risk of severe hypotension.
  • Have a known hypersensitivity or allergic reaction to sildenafil or any component of the tablet.

Precautions (Use with Caution)

Consultation with a healthcare provider is essential, as the drug may be inadvisable for those with:

Condition
Severe cardiovascular conditions (e.g., recent heart attack or stroke within the last six months, unstable angina, uncontrolled high or low blood pressure).
Hereditary eye conditions like retinitis pigmentosa, or a history of severe vision loss.
Blood cell disorders (e.g., sickle cell anemia, multiple myeloma, leukemia) due to the risk of priapism (a prolonged, painful erection).
Anatomical deformity of the penis (e.g., Peyronie's disease).
Severe liver or kidney problems.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Sildaristo (Sildenafil) has officially documented interactions that govern its co-administration with other substances, classified based on the level of risk and mechanism of action, according to regulatory sources.

Formal Contraindications

The co-administration of Sildaristo is strictly contraindicated with specific classes of medicines due to the high risk of severe hypotension (critically low blood pressure):

Category Example Entities
Nitric Oxide (NO) Donors Organic Nitrates (e.g., Nitroglycerin)
Guanylate Cyclase Stimulators Riociguat

Pharmacokinetic and Pharmacodynamic Interactions

Interactions primarily occur through Sildenafil's metabolism, which is mainly mediated by the Cytochrome P450 (CYP) 3A4 enzyme, and through additive effects on blood vessels.

  • Exposure Modification: Potent CYP3A4 inhibitors (e.g., Ritonavir, Ketoconazole) increase Sildenafil's systemic exposure (AUC/Cmax) and require official cautions regarding maximum allowed doses. Conversely, CYP3A4 inducers (e.g., Bosentan) may decrease Sildenafil levels.
  • Additive Hypotension: Co-administration with alpha-blockers or other antihypertensive agents may result in symptomatic drops in blood pressure due to enhanced vasodilatory effects. The regulatory label notes this effect is most likely to occur within four hours of Sildenafil administration.

Consumption and Population Cautions

Official regulatory documents note that consumption of alcohol (ethanol) can increase the risk of hypotension, and grapefruit juice may cause modest increases in Sildenafil concentrations. Furthermore, Sildenafil clearance is reduced in individuals with severe hepatic impairment, leading to elevated systemic exposure.

Mechanism of Action

How Sildaristo Works: Mechanism of Action

Sildaristo acts as a selective, competitive inhibitor of the enzyme Phosphodiesterase Type 5 (PDE5), which is highly localized in the smooth muscle of blood vessels, including those in the lungs and the corpus cavernosum. Inhibition of PDE5 prevents the breakdown of its substrate, cyclic Guanosine Monophosphate (cGMP), thereby causing cGMP levels to be sustained within the smooth muscle cells.

This preservation of cGMP amplifies the natural Nitric Oxide (NO) signal, as Sildaristo functions as a modulator of the existing NO-cGMP signaling pathway. Elevated cGMP activates a protein kinase cascade that reduces the intracellular calcium concentration required for muscle contraction.

At the tissue level, this molecular cascade causes the relaxation of vascular smooth muscle and subsequent vasodilation. This physiological consequence results in a reduction in vascular resistance and permits increased blood inflow to specific targeted vascular beds.

Dosage and Administration Information

How Sildaristo is Used

The administration of Sildaristo (Sildenafil) is defined by two distinct dosing schedules, with the specific route and frequency depending on the intended use pattern. The drug is primarily administered by the oral route as a film-coated tablet, although an intravenous (IV) injection is available for temporary use in hospital settings.

Official Dosing and Administration

Usage Pattern Starting Oral Dose Maximum Daily Dose Frequency
As-Needed Use 50 mg 100 mg Maximum of once per day
Scheduled Use 20 mg 80 mg (TID) Three times a day (TID)

For as-needed use, the oral tablet is typically taken approximately one hour before activity, but the timing may range from 30 minutes to four hours. It is stated that taking the tablet with food may delay the onset of activity.

Administration Requirements

Instructions specify that dosage modifications are necessary for certain patient populations. For the as-needed regimen, a lower initial dose of 25 mg should be considered for older adults (65 years and over) and for individuals with severe hepatic or renal impairment.

For the scheduled use regimen, doses must be spaced approximately four to six hours apart. If an oral suspension form is prescribed, it requires reconstitution with water and must be measured using a calibrated device. In the event of a missed dose for the scheduled regimen, guidance directs the patient to take the next dose as soon as possible and resume the regular schedule, without taking a double dose.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Sildaristo


Evidence for use in Erectile Dysfunction (ED)

Research examining Sildenafil for adult men with ED included large, randomized, placebo-controlled trials (RCTs). These studies were designed to evaluate short-term changes over periods generally ranging from a few weeks up to six months. Studies explored specific subgroups of men with co-existing conditions, such as diabetes mellitus, status post-prostatectomy, or spinal cord injury. The research evaluated outcomes related to physical discomfort and patient-reported experiences, using standardized questionnaires to measure changes in outcomes reflecting daily functioning or activity level.

Studies explored patterns related to how participants reported their experiences and research examined changes in functional scores compared to the control groups. These findings describe patterns observed in the studies and help contextualize how patients reported their experience over the observation period. The evidence contributes to understanding symptom patterns relevant in trials assessing short-term or episodic symptom patterns of ED.


Evidence for use in Pulmonary Arterial Hypertension (PAH)

The evidence for Sildenafil in Pulmonary Arterial Hypertension (PAH) was studied for in short-term randomized, double-blind, placebo-controlled trials. These studies evaluated patients with conditions marked by functional limitations and sought to measure changes in outcomes reflecting daily functioning or activity level. Studies explored specific endpoints, such as the 6-Minute Walk Distance (6MWD), and monitored the time until patients experienced a defined event of clinical worsening.

Research describes changes measured during the study period for exercise capacity outcomes. Studies also examined the time to clinical worsening, describing the duration of time elapsed before a defined event was observed in the study populations. Data show patterns related to outcomes reflecting daily functioning or activity level in adults in the short term. However, when research examined outcomes related to all-cause mortality as a single primary endpoint in these short-term trials, findings were mixed.


Long-Term Evidence and Durability of Follow-Up

Research efforts have included long-term observation to track the sustained patterns related to Sildenafil in clinical studies. These extended-duration studies typically involved open-label settings, where researchers continued to monitor participants over several years. This research contributes to the broader evidence landscape by collecting data on long-term patient-reported outcomes and functional status beyond the initial controlled trial period.

However, long-term outcomes are not fully established across all clinical contexts. While studies monitored responses over defined time intervals, there is limited information for outcomes that extend well beyond the multi-year observation period, especially concerning the durability of response and its consistency in all patient groups.

Key Studies & References

  1. A Randomized, Double-Blind, Placebo-Controlled Study of Sildenafil in Children With Pulmonary Arterial Hypertension (STARTS Trial - NCT00159913)

Frequently Asked Questions (FAQ)

Common questions about Sildaristo (FAQ)


Q: How quickly does Sildaristo start working?

A: According to official product information, the active ingredient is generally absorbed rapidly. While the time frame can vary, the onset of action is generally observed within about one hour after taking the tablet, with effects potentially beginning as early as 30 minutes or as long as four hours.


Q: How long do the effects of Sildaristo last?

A: The duration of the therapeutic response is related to the drug's half-life, which is approximately 3 to 5 hours. This means the drug's action persists for several hours, though the duration of the observable effect can vary from person to person.


Q: Does Sildaristo affect your blood pressure?

A: Yes, regulatory documents indicate that Sildaristo has systemic vasodilatory properties, meaning it widens blood vessels. This action may be associated with a mild and temporary reduction in blood pressure. This is why caution is advised when combining it with other blood pressure-lowering medications.


Q: Can Sildaristo affect the eyesight long-term?

A: Official information reports that most visual symptoms, such as temporary color changes, are transient and reversible. Regulatory sources also describe rare, serious eye events (like NAION). However, regulatory information does not describe common long-term toxic effects on the eyesight at standard prescribed doses.


Q: What if I take Sildaristo but don't have sex?

A: Sildaristo for erectile dysfunction (ED) is intended to be taken as needed before sexual activity. The medication requires sexual stimulation to work properly by enhancing blood flow. If sexual stimulation does not occur, the medication is typically not expected to produce an erection.


Q: Can Sildaristo be taken on an empty stomach?

A: Yes, official product information states that Sildaristo may be taken with or without food. Official data indicates that if the medication is taken on an empty stomach, the onset of action may be faster.


Q: How does a high-fat meal affect Sildaristo's absorption?

A: If Sildaristo is consumed after a high-fat meal, the medication's absorption into the bloodstream may be delayed. This means it may take a little longer for the drug to start working compared to taking it without food.


Q: Why is Sildaristo available in different strengths?

A: Different strengths exist to allow for individual dose adjustments (titration) based on a patient’s needs and how well they tolerate the medicine. The specific dose is determined by a prescriber.


Q: Can Sildaristo be taken every day?

A: This depends on the condition being treated. For erectile dysfunction, the maximum recommended frequency is once per day on an 'as needed' basis. When used for Pulmonary Arterial Hypertension (PAH), it is typically taken on a regular scheduled regimen, which may involve multiple doses per day.


Q: Can you take Sildaristo if you are on antidepressants?

A: No major drug-specific interactions are known with Sildaristo and most common antidepressants. However, some types of antidepressants may carry a small additive risk of hypotension (low blood pressure). Patients should always review their full medication list with a prescriber, as an assessment of potential interactions is needed.


Q: Does Sildaristo affect fertility or sperm quality?

A: Clinical studies involving healthy volunteers showed no significant differences between the active ingredient, Sildenafil, and a placebo regarding effects on sperm motility, morphology (shape), or overall count. Official information does not indicate an impact on fertility.


Q: Does Sildaristo work if your ED is psychological?

A: Sildaristo acts directly on the physical mechanism of the erection by promoting blood flow. The drug’s mechanism is based on treating the physiological inability to achieve or maintain an erection, regardless of the cause being physical or psychological.


Q: Why does Sildaristo sometimes cause back pain?

A: Official documentation lists both back pain and muscle pain as possible common side effects associated with the use of Sildenafil. These are generally considered common adverse reactions, though the exact physiological reason for the pain in all cases is not fully specified.


Q: Are the side effects worse the higher the dose of Sildaristo?

A: Official clinical studies have suggested a dose-response relationship for some common side effects. This means that individuals who took higher doses of Sildaristo were more likely to report common adverse reactions like headaches and indigestion compared to those taking lower doses.


Q: How is Sildaristo used to treat pulmonary hypertension?

A: For the treatment of Pulmonary Arterial Hypertension (PAH), Sildaristo is used on a scheduled regimen, typically taken multiple times a day. The purpose is to continuously relax blood vessels in the lungs to reduce pulmonary blood pressure.


Q: What happens if you miss a dose of Sildaristo (in the case of regular use)?

A: Official regulatory guidance regarding a missed scheduled dose (e.g., for PAH treatment) indicates that the dose is to be taken as soon as possible, and the patient should then resume the regular schedule. Regulatory guidance specifies that a double dose should not be taken to make up for the missed one.


Q: Can Sildaristo make heartburn or indigestion worse?

A: Official safety data lists dyspepsia (a term for indigestion or upset stomach) as a common side effect of Sildaristo. Therefore, based on its adverse reaction profile, the medication has the potential to cause or exacerbate symptoms of heartburn or indigestion.


Q: Can women use Sildaristo, and if so, what for?

A: Yes, the active ingredient, Sildenafil, is approved for use in both men and women. Its approved use for both genders is the treatment of Pulmonary Arterial Hypertension (PAH).


Q: Is Sildaristo used for conditions other than ED in children?

A: Yes, Sildenafil is approved to treat Pulmonary Arterial Hypertension (PAH) in certain children. Its use and specific administration in pediatric populations are subject to detailed regulatory guidelines and specialist assessment.

How should Sildaristo be stored and disposed of?

Sildaristo must be stored and handled according to specific regulatory instructions to maintain its stability and effectiveness.

Required Storage Conditions

The medicine must be kept out of the sight and reach of children. Tablets should be stored in the original package to ensure protection from moisture and light.

Requirement Condition
Temperature Room temperature, typically 20 C to 25 C (68 F to 77 F), unless specified otherwise.
Container Keep in the original container, tightly closed.

Disposal Instructions

Do not use the medicine after the stated expiry date (EXP). Do not throw away Sildaristo via wastewater or household waste. Expired or unused tablets must be disposed of by following local environmental regulations or by consulting a pharmacist for proper collection methods.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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