Sildenafil, commonly known as Viagra, is a phosphodiesterase type 5 (PDE5) inhibitor prescribed for erectile dysfunction and pulmonary arterial hypertension. Understanding how long sildenafil takes to wear off is essential for safe and effective use. The medication typically provides therapeutic effects for approximately 4 hours, though it remains detectable in your system for up to 24 hours. Individual factors such as age, liver function, and concurrent medications can influence both the duration of effects and elimination time. This article explains sildenafil's pharmacokinetics, when effects diminish, and what to expect as the medication leaves your body.

How Long Does Sildenafil Stay in Your System?

Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor used primarily to treat erectile dysfunction (ED) under brand names like Viagra, while a lower dose formulation (Revatio) is used for pulmonary arterial hypertension. Understanding how long this medication remains active in your body is important for both efficacy and safety considerations.

Pharmacokinetic profile: After oral administration, sildenafil reaches peak plasma concentrations within approximately 30 to 120 minutes, with an average of around one hour when taken on an empty stomach. The medication has a half-life of approximately 3 to 5 hours in most individuals. This means that after this time period, half of the drug has been metabolised and eliminated from your bloodstream. However, the half-life represents only part of the picture when considering how long effects persist.

For complete elimination, it generally takes four to five half-lives for a drug to be substantially cleared from the body. Therefore, sildenafil is typically eliminated from your system within 15 to 25 hours after taking a single dose. This timeframe can vary based on individual factors such as age, liver function, and kidney function.

Clinical implications: Whilst the drug may remain detectable in your system for up to 24 hours, the therapeutic effects for erectile dysfunction—specifically the ability to achieve and maintain an erection—typically last for up to about 4 hours after administration, with some men experiencing effects for up to 6 hours. It is important to note that sildenafil does not cause continuous erections but rather facilitates the physiological response to sexual stimulation during this window of activity.

Factors That Affect How Long Sildenafil Lasts

The duration of sildenafil's effects and its elimination from the body can vary considerably between individuals due to several physiological and lifestyle factors. Understanding these variables helps set realistic expectations and ensures safe medication use.

Age-related considerations: Older adults (aged 65 and above) typically experience prolonged sildenafil effects. Age-related changes in hepatic metabolism and renal clearance mean the drug is processed more slowly, potentially extending both therapeutic effects and the presence of the medication in the system. The SmPC and BNF suggest that elderly patients may benefit from a lower starting dose (25 mg) to account for these pharmacokinetic differences.

Hepatic and renal function: The liver is primarily responsible for metabolising sildenafil through the cytochrome P450 enzyme system, particularly CYP3A4 and CYP2C9. Individuals with hepatic impairment (such as cirrhosis) may experience significantly prolonged drug effects and should typically start with lower doses (25 mg). Similarly, severe renal impairment (creatinine clearance <30 mL/min) can reduce drug clearance, necessitating dose modification.

Food and alcohol intake: Taking sildenafil with a high-fat meal can delay absorption by up to one hour and may reduce peak plasma concentrations, potentially diminishing effectiveness. Whilst moderate alcohol consumption does not significantly alter sildenafil pharmacokinetics, excessive alcohol can impair erectile function independently and may increase the risk of adverse effects such as dizziness or hypotension.

Drug interactions: Certain medications can significantly affect sildenafil metabolism:

• Contraindicated combinations: Sildenafil must never be used with nitrates (including GTN, isosorbide mononitrate/dinitrate), nicorandil, or recreational 'poppers' (amyl nitrite) due to potentially dangerous blood pressure drops. It is also contraindicated with riociguat.

• CYP3A4 inhibitors (such as erythromycin, ketoconazole) can increase sildenafil levels. With protease inhibitors like ritonavir, the maximum dose should be limited to 25 mg and not taken more often than once in 48 hours.

• Alpha-blockers: Use with caution; patients should be stable on alpha-blocker therapy before starting sildenafil, and a 25 mg starting dose should be considered to reduce the risk of postural hypotension.

• Grapefruit juice is a CYP3A4 inhibitor and should be avoided or limited when taking sildenafil.

Patients should always inform their GP or pharmacist about all medications they are taking, including over-the-counter products and herbal supplements.

When Sildenafil Effects Start to Wear Off

The therapeutic window of sildenafil—the period during which it effectively facilitates erectile function—follows a predictable pattern, though individual experiences may vary.

Peak effectiveness: Sildenafil typically begins working within 30 to 60 minutes of ingestion, with peak plasma concentrations and maximal effect occurring around the one-hour mark. During this peak period, the medication is most effective at facilitating erections in response to sexual stimulation. It is crucial to understand that sildenafil does not produce spontaneous erections; sexual arousal is still required for the medication to work.

Duration of therapeutic effect: For most men taking the standard 50 mg dose for erectile dysfunction, the ability to achieve erections remains enhanced for approximately 4 hours after taking the tablet, with some men experiencing effects for up to 6 hours. Some men report effects lasting slightly longer, whilst others may notice diminished effectiveness after 3 to 4 hours. Higher doses (100 mg) primarily increase the magnitude of effect rather than substantially extending duration.

Gradual decline: As sildenafil is metabolised and eliminated, its effects diminish gradually rather than stopping abruptly. You may notice that erections become somewhat less firm or that more stimulation is required as the medication's effects begin to wear off. This gradual tapering is normal and reflects the declining plasma concentrations of the active drug.

Individual variation: Some men with faster metabolic rates may find effects wear off closer to the 3-hour mark, whilst those with slower metabolism (particularly older adults or those with hepatic impairment) may experience effects lasting longer. If you consistently find that sildenafil wears off too quickly or lasts longer than expected, discuss this with your GP, as dose adjustment or investigation of underlying factors may be appropriate.

What to Expect After Sildenafil Wears Off

Once sildenafil's therapeutic effects have diminished, your body returns to its baseline state. Understanding what is normal during this period can help alleviate concerns and ensure appropriate management of any lingering effects.

Return to baseline erectile function: After sildenafil wears off, erectile function returns to your pre-medication state. This means that if you have underlying erectile dysfunction, the difficulty achieving or maintaining erections will resume. Sildenafil does not cure ED; it provides temporary symptomatic relief. There is no 'rebound' worsening of erectile function after the medication leaves your system—your baseline function remains unchanged.

Resolution of haemodynamic effects: Sildenafil causes mild vasodilation, which can result in slight decreases in blood pressure (typically 8-10 mmHg systolic and 5-6 mmHg diastolic). These effects peak around 1-2 hours after taking the dose and are transient. Most men do not notice these subtle changes, but if you experienced mild dizziness or flushing whilst the medication was active, these symptoms should resolve as the drug is eliminated.

No withdrawal symptoms: Sildenafil does not cause physical dependence, and there are no withdrawal symptoms when it wears off. You can safely use it on an as-needed basis without concern for tolerance or dependence developing. However, some men may experience psychological reliance, feeling anxious about sexual performance without the medication. If this becomes a concern, discussing it with your GP or a psychosexual therapist may be beneficial.

Timing of subsequent doses: For erectile dysfunction, the NHS and product information advise that sildenafil should not be taken more than once in a 24-hour period. Even after effects have worn off (typically after 4 hours), you should wait the full 24 hours before taking another dose to avoid excessive drug accumulation and increased risk of adverse effects. Note that dosing for pulmonary arterial hypertension (Revatio) follows a different schedule as prescribed by specialists.

Managing Side Effects as Sildenafil Leaves Your Body

Most side effects of sildenafil are mild and transient, resolving naturally as the medication is metabolised and eliminated. However, knowing how to manage these effects and recognising when to seek medical attention is important for safe use.

Common side effects and their resolution: According to the SmPC, the most frequently reported adverse effects include headache (occurring in approximately 16% of users), flushing (10%), dyspepsia (7%), nasal congestion (4%), and visual disturbances such as mild colour tinge or increased light sensitivity (3%). These effects typically resolve within 12 to 24 hours as sildenafil clears from your system. For headaches, simple analgesia such as paracetamol is usually sufficient. Staying well-hydrated may help reduce the intensity of headaches and flushing.

Visual and hearing disturbances: Temporary changes in colour perception (particularly a blue tinge) or increased sensitivity to light occur because sildenafil has mild activity against PDE6, an enzyme present in the retina. These effects are generally harmless and resolve completely as the drug is eliminated. However, if visual changes persist beyond 24 hours or if you experience sudden vision loss, call 999 or go to A&E immediately, as this could indicate non-arteritic anterior ischaemic optic neuropathy (NAION), a rare but serious complication. Similarly, sudden hearing loss or tinnitus requires immediate medical attention—stop taking sildenafil and seek urgent medical advice.

Cardiovascular considerations: If you experience chest pain during or after sexual activity whilst taking sildenafil, do not take nitrate medications (such as GTN spray or tablets), as this combination can cause severe, potentially life-threatening hypotension. Call 999 immediately and inform them that you have taken sildenafil.

When to seek emergency medical help: Call 999 or go to A&E if you experience:

• Priapism (erection lasting more than 4 hours)—this is a medical emergency requiring immediate treatment to prevent permanent damage

• Severe dizziness or fainting

• Chest pain or palpitations

• Sudden vision or hearing loss

• Severe allergic reactions (rash, swelling, difficulty breathing)

Contact your GP if you experience side effects that persist beyond 24 hours or significantly impact your quality of life. You can also report any suspected side effects to the MHRA Yellow Card Scheme at yellowcard.mhra.gov.uk.

Most men tolerate sildenafil well, and side effects diminish predictably as the medication wears off. If you have concerns about side effects or the medication's duration of action, your GP can discuss alternative PDE5 inhibitors or adjust your dosage to optimise both efficacy and tolerability.

Frequently Asked Questions