Spedra Side Effects: Complete Safety Guide
When Do Side Effects Start? How Long Do They Last? Timeline, Contraindications & Food Interactions
Key Takeaways: Spedra Side Effects
- Most common: Headache, flushing, nasal congestion (affect up to 1 in 10 men).
- Onset: Side effects usually begin within 30–60 minutes of taking the tablet.
- Duration: Typically resolve within 4–6 hours, matching the drug's active period.
- Serious side effects: Priapism (erection >4 hours), sudden vision loss, chest pain – seek emergency help.
- Contraindications: Do not use with nitrates, strong CYP3A4 inhibitors, or if you have severe heart/liver problems.
- Food: Grapefruit juice increases side effect risk; avoid within 24 hours.
Understanding Spedra (avanafil) side effects helps you use it safely and recognise when to seek medical advice. This guide covers when side effects start, how long they last, full lists by frequency, who should avoid it, and important interactions with food and alcohol – all based on the official patient information leaflet and clinical data.
Important Medical Advice
Stop taking Spedra and see a doctor immediately if you experience: an erection lasting more than 4 hours (priapism), sudden decrease or loss of vision in one or both eyes, sudden decrease or loss of hearing (sometimes with dizziness or ringing in the ears), or chest pain. These are rare but serious side effects requiring urgent treatment.
Common Side Effects of Spedra
Like all medicines, Spedra can cause side effects, although not everyone gets them. The frequencies below are based on clinical trial data and the patient information leaflet.
Very common and common (may affect up to 1 in 10 people)
- Headache – the most frequently reported side effect.
- Flushing (redness of the face, neck, or chest).
- Nasal congestion (stuffy nose).
Uncommon (may affect up to 1 in 100 people)
- Dizziness, feeling sleepy or very tired
- Sinus congestion, back pain
- Hot flush, feeling out of breath when exerting yourself
- Heartbeat changes seen on ECG, increased heart rate, palpitations
- Indigestion, feeling sick (nausea), being sick (vomiting)
- Blurred vision
- Raised liver enzymes (detected in blood tests)
Rare (may affect up to 1 in 1,000 people)
- Influenza, influenza‑like illness, stuffy or runny nose, hayfever
- Congestion in nose, sinuses, or upper airway
- Gout, trouble sleeping (insomnia), premature ejaculation
- Feeling strange, feeling unable to keep still
- Chest pain, serious chest pain (angina), fast heart rate, high blood pressure
- Dry mouth, stomach ache, heartburn, lower abdominal pain, diarrhoea
- Rash, pain in lower back or side of lower chest, muscle aches or pains, muscle spasms
- Frequent urination, penile disorder, spontaneous erection without stimulation
- Itching in genital area, feeling weak or tired all the time, swelling in feet or ankles
- Increased blood pressure, pink or red urine (blood in urine)
- Abnormal extra heart sound, elevated PSA, elevated bilirubin, elevated creatinine
- Weight gain, fever, nosebleed
🗒️ Note: This list includes all side effects reported in clinical trials. Most are mild and temporary. If any side effect bothers you or persists, talk to your doctor or pharmacist.
When Do Side Effects Start?
Side effects from Spedra usually begin within 30–60 minutes after taking the tablet. This timing aligns with the drug's absorption and peak concentration in the bloodstream.
For example, headache and flushing often appear as avanafil levels rise, typically peaking alongside the drug's maximum effect. If you take Spedra with a high‑fat meal, absorption is delayed, so side effects may start later – around 60–90 minutes after dosing.
Some men may experience side effects sooner (within 15–20 minutes) if they are particularly sensitive or have taken a higher dose (200mg).
🗒️ Tip: If you are prone to headaches, staying well hydrated may help. Mild side effects often lessen as your body gets used to the medication.
How Long Do Side Effects Last?
The duration of side effects is closely linked to how long avanafil remains active in your body. The drug has a half‑life of 5–10 hours, meaning its concentration declines over that period. Most side effects resolve within 4–6 hours after taking the tablet, as the drug levels fall.
For example, a headache might last 2–4 hours, while flushing usually fades within 1–2 hours. Rarely, some individuals may experience lingering mild effects for up to 12 hours, but this is uncommon.
If side effects persist beyond 12 hours or are severe, contact your doctor for advice.
Side Effects Timeline
Here’s a typical timeline of side effects after taking a standard 100mg dose of Spedra on an empty stomach:
| Time after dose | What happens |
|---|---|
| 0–30 minutes | Drug being absorbed; some sensitive individuals may notice early flushing or nasal congestion. |
| 30–60 minutes | Peak drug levels; most common side effects (headache, flushing) are most likely to appear now. |
| 1–4 hours | Side effects may persist but gradually diminish as drug levels decline. |
| 4–6 hours | Most side effects have resolved or become very mild. |
| 6–12 hours | Occasional mild residual effects (e.g., slight headache) possible but rare. |
| 12–24 hours | Side effects should be completely gone; drug is mostly eliminated. |
🗒️ Remember: This timeline is typical but can vary based on individual metabolism, dose, and food intake.
Contraindications (Who Should NOT Use Spedra)
Do not take Spedra if any of the following apply to you:
- Allergy to avanafil or any other ingredient.
- Taking nitrates for chest pain (e.g., glyceryl trinitrate, isosorbide mononitrate, amyl nitrite) – this can cause a severe drop in blood pressure.
- Taking HIV medications (ritonavir, indinavir, saquinavir, nelfinavir, atazanavir).
- Taking certain antifungals (ketoconazole, itraconazole, voriconazole) or antibiotics (clarithromycin, telithromycin).
- Serious heart problem, or had a heart attack or stroke in the last 6 months.
- Low blood pressure or uncontrolled high blood pressure.
- Chest pain (angina) or chest pain during sexual intercourse.
- Severe liver or kidney problem (including end‑stage renal disease on dialysis).
- Loss of vision due to non‑arteritic anterior ischaemic optic neuropathy (NAION).
- Hereditary eye disease like retinitis pigmentosa.
- Taking riociguat (for pulmonary hypertension).
Also, do not use Spedra with other erectile dysfunction treatments (sildenafil, tadalafil, vardenafil).
🗒️ Warning: If you are unsure whether any of these apply, speak to your doctor or pharmacist before taking Spedra.
Food & Alcohol Interactions
Grapefruit juice
Avoid grapefruit juice for 24 hours before taking Spedra. Grapefruit juice inhibits CYP3A4, the enzyme that breaks down avanafil, leading to increased drug levels and a higher risk of side effects (headache, flushing, dizziness).
Alcohol
Drinking alcohol at the same time as Spedra may increase the chance of dizziness, headache, and rapid heartbeat (palpitations). Alcohol can also temporarily impair your ability to get an erection. Moderation is key: 1–2 units are usually safe, but binge drinking should be avoided.
Food in general
Spedra can be taken with or without food. However, a high‑fat meal (e.g., full English breakfast, fried foods) delays absorption and may slightly reduce peak drug levels. This means side effects may start later and be milder, but the medicine may also take longer to work.
Spedra Side Effects FAQs
Can Spedra cause vision problems?
Rarely, Spedra may cause blurred vision or a sudden loss of vision in one or both eyes (NAION). If you experience vision changes, stop taking Spedra and seek medical help immediately.
Is it safe to take Spedra with blood pressure medication?
It depends on the medication. Some BP drugs (alpha‑blockers) may interact. Always inform your doctor about all medications you take. Spedra is generally safe with most BP meds if blood pressure is well controlled.
What should I do if I get a painful erection lasting more than 4 hours?
This is a medical emergency (priapism). Go to the nearest Accident & Emergency (A&E) department immediately. Delayed treatment can cause permanent damage to your penis.
Can I drink grapefruit juice while taking Spedra?
No, avoid grapefruit juice for 24 hours before taking Spedra. It increases drug levels and raises the risk of side effects.
Are Spedra side effects worse with the 200mg dose?
Yes, side effects are dose‑related. The 200mg dose may cause more frequent or intense side effects, especially headache and flushing. Your doctor will prescribe the lowest effective dose.
Need a Prescription for Spedra?
If you're considering Spedra and want to discuss potential side effects with a doctor, start an online consultation today.
Safe & Discreet Service
MHRA-compliant | GPhC-registered pharmacy | Confidential | Next‑day delivery
Start Spedra ConsultationRelated Spedra Guides
Medical Content Manager
Nabeel is a co-founder, and medical content manager of Chemist Doctor. He works closely with our medical team to ensure the information is accurate and up-to-date.
Medical Doctor
Dr. Feroz is a GMC-registered doctor and a medical reviewer at Chemist Doctor. He oversees acute condition and urgent care guidance.
Medical Director
Usman is a co-founder, and medical director of Chemist Doctor. He leads the organisation's strategic vision, bridging clinical and operational priorities.
Review Date: 14 February 2026
Next Review: 14 August 2026
Published on: 14 February 2026
Last Updated: 14 February 2026