Brand Viagra (Sildenafil Citrate) – Comprehensive Patient Guide
Basic Product Information
| International Nonproprietary Name (INN) | Sildenafil Citrate |
|---|---|
| Australia Brand Names | Viagra, Sildegra, Vedafil (generic brands may vary) |
| Anatomical Therapeutic Chemical (ATC) Code | G04BE03 |
| Available Forms & Strengths | Tablets: 25mg, 50mg, 100mg (film-coated) |
| Manufacturers | Pfizer Australia Pty Ltd (Viagra); Various for generics |
| Prescription Status | Prescription Only Medicine (Schedule 4, S4) |
Mechanism of Action
For Patients: Viagra works by improving blood flow to the penis, helping men achieve and maintain an erection when sexually aroused. It does not cause an erection without sexual stimulation.
For Healthcare Professionals: Sildenafil Citrate is a selective phosphodiesterase type 5 (PDE5) inhibitor. By inhibiting PDE5 in the corpus cavernosum, it increases cyclic GMP concentration, causing relaxation of smooth muscle and enhancing erectile response to sexual stimulation.
Pharmacokinetics
- Absorption: Rapidly absorbed after oral administration. Peak plasma concentrations (Tmax) occur in 30–120 minutes (median 60 minutes).
- Metabolism: Primarily hepatic via CYP3A4 and, to a lesser extent, CYP2C9 pathways.
- Elimination: Predominantly as metabolites in faeces (approx. 80%) and urine (approx. 13%). Terminal half-life ~3–5 hours.
- Duration of Action: Effective 4–6 hours post-dose, though individual response varies.
Use in Everyday Life and Best Practices
- Typical Doses: Start with 50mg, taken as needed about 1 hour before sexual activity. Dose may be adjusted between 25mg and 100mg based on efficacy and tolerability, as advised by your doctor.
- How to Use: Swallow the tablet whole with water, without chewing or crushing.
- Contextual Advice: Viagra should only be used once per day and not more frequently. It is not intended for continuous daily use unless your doctor specifically prescribes it for another condition (e.g., pulmonary arterial hypertension).
- Storage: Store below 25°C, away from light and moisture. Keep out of reach of children.
Dosing: Morning vs Evening
Take Viagra about 1 hour before anticipated sexual activity, regardless of the time of day. Morning vs Evening Considerations:
- Morning: Can be taken in the morning if sexual activity is expected; be mindful of work and social obligations.
- Evening: Most patients use Viagra in the evening, aligning with commonly preferred intimate times and reducing interference with work or daytime routines.
- Tips for Regularity: Using at roughly the same time can help remember dosing, but only take as needed within prescribed limits.
Taking with Food or on an Empty Stomach
- Viagra works best taken on an empty stomach or after a light meal.
- High-fat meals (like fish and chips or a heavy curry) can delay absorption, slowing the onset of effect.
- If you typically enjoy a substantial dinner (e.g., typical English roast), allow extra time before taking Viagra or consider a lighter meal to optimise effectiveness.
Interaction Warnings
| Interaction | Advice |
|---|---|
| Food | High-fat meals may delay effect. Light, balanced meals preferred prior to use. |
| Alcohol | Excessive alcohol may reduce response, increase side effects (dizziness, lowered blood pressure). Moderate intake is advised. |
| Nitrates (Angina Medicines) | Severe risk of dangerous fall in blood pressure. MUST NOT BE USED together. |
| Alpha-blockers (for prostate/blood pressure) | May further lower blood pressure. Consult with doctor about timing and dose safety. |
| Other PDE5 inhibitors (Tadalafil, Vardenafil, Avanafil) | Do not combine. Increased risk of serious side effects. |
| Other medicines | Antifungals, some antibiotics (e.g. erythromycin), HIV medicines may increase Sildenafil levels. |
| Herbal supplements | St John’s wort, ginkgo may interact — consult your pharmacist or doctor. |
Indications
| Indication | Official/Off-Label | Evidence Level |
|---|---|---|
| Erectile Dysfunction (ED) in adult men | Official / TGA Registered | High |
| Pulmonary Arterial Hypertension (specialist use; different brand, PAH dose) | Official (as Revatio, specialist supervision) | High |
| Raynaud’s Phenomenon, Antidepressant-induced sexual dysfunction | Off-label | Moderate; consult specialist |
Dosing According to Clinical Indication
| Indication | Patient Group | Recommended Dose | Notes |
|---|---|---|---|
| ED (Erectile Dysfunction) | Male adults (18–65) | 50mg as needed, 30–60 minutes before sexual activity. Max 100mg/day. | Adjust dose to 25mg or 100mg based on individual response & side effects. |
| ED in Elderly (>65 yrs) | Males >65 | 25mg as needed; may increase to 50mg if tolerated. | More sensitive to side effects; start low. |
| ED in Renal or Hepatic Impairment | Adults | 25mg as needed | Consult specialist; monitor closely. |
| Use in Women & Children | Not licensed | Not recommended; off-label & specialist only (e.g. for PAH) | See specialist paediatrician for PAH indication. |
Safety Profile & Side Effects
Viagra is considered very safe when used as prescribed, but like all medicines it can cause side effects. Stop use and seek help if you have serious symptoms.
| Frequency | Side Effects |
|---|---|
| Common (>1 in 100) | Headache, flushing, indigestion, stuffy or runny nose, dizziness, visual disturbance (blurred vision, blue tinge) |
| Occasional | Back pain, muscular aches, mild nausea, rash, increased heart rate |
| Rare/Serious | Priapism (prolonged erection >4 hours), sudden loss of vision/hearing, chest pain, severe allergic reactions (anaphylaxis) |
- Avoid driving or operating machinery if you experience dizziness or vision changes.
- Immediately seek medical help for chest pain, loss of vision, or erections longer than 4 hours.
- Medical conditions like severe heart disease, recent stroke, or very low blood pressure may make Viagra unsafe—discuss your history with your GP or pharmacist.
Guidelines for Proper Use (Australian Context)
- Use only as prescribed by an Australian-registered doctor or specialist.
- Discuss all medicines (including herbal and pharmacy products) with your pharmacist or GP before starting Viagra.
- Do not purchase Viagra from unauthorised sources—counterfeit products are a significant risk online.
- Keep all appointments for follow-up review, especially if you have chronic conditions (heart, liver, kidney issues).
- Contact your doctor/pharmacist if you’re unsure when or how to take your dose.
- Do not share your medicine with others.
- Australian health services offer confidential sexual health and men’s health clinics for further support.
Alternative Treatment Options
- Tadalafil (Cialis, generic brands): Longer-acting; can be taken daily or as needed. Fewer dietary interactions, but cost is commonly higher. PBS subsidised for specific indications (not ED).
- Vardenafil (Levitra): Similar onset and duration to sildenafil; may be better tolerated by some patients.
- Avanafil (Spedra): Newer, very rapid onset. Less widely available in Australia.
- Injection and device therapies: For those who cannot take oral medication or have not responded to tablets. Include alprostadil, vacuum devices.
- Testosterone supplementation: For men with proven deficiency; requires specialist supervision.
- Non-pharmaceutical approaches: Psychological therapy, couple’s counselling, lifestyle changes (weight, smoking, exercise).
Note: Most oral PDE5 inhibitors are not reimbursed under the PBS for erectile dysfunction; patients usually pay privately.
Legal, Registration, and Reimbursement Status in Australia
- Registered with the Therapeutic Goods Administration (TGA) for sexual dysfunction and (as Revatio) for PAH.
- Prescription-only (Schedule 4/S4) – only available from a registered pharmacy with a valid prescription.
- Generally not PBS subsidised for the erectile dysfunction indication; private prescription cost varies between pharmacies.
- Available as branded (Viagra) and multiple generic forms.
Latest Research & Clinical Guidance (2022–2025)
- Recent guidelines from the Royal Australian College of General Practitioners (RACGP) and Australasian Society for Sexual Health recommend PDE5 inhibitors as first-line therapy for ED (RACGP, 2022).
- 2023 update in the British Journal of Urology International highlights comparable efficacy and safety for all PDE5 inhibitors, supporting personalised medicine approach (BJUI, 2023).
- Meta-analyses and clinical reviews confirm sustained efficacy and tolerability with long-term use in men with comorbidities (Australian Family Physician, 2022).
Availability and Delivery
| Pack sizes | Approximate retail price (AUD) | Home delivery (major cities) |
|---|---|---|
| 4 tablets (50mg) | $39–$59 | 1–2 days (Sydney, Melbourne, Brisbane, Perth) |
| 8 tablets (50mg/100mg) | $74–$110 | 1–3 days (Adelaide, Canberra, Hobart, Darwin) |
| 12–24 tablets (generics) | $120–$180 | 1–5 days (regional Australia) |
- Online Australian pharmacies may offer express shipping with secure, discreet packaging.
- Always check the pharmacy is approved by the Pharmacy Board of Australia and offers pharmacist advice.
FAQ – Your Top Questions Answered
- Do I need a prescription for Viagra in Australia?
Yes. Viagra and its generic equivalents are prescription-only medicines in Australia. See your GP or sexual health doctor for assessment and prescription. - Is it safe to buy Viagra online?
Only buy from licensed, Australian-registered pharmacies that require a prescription. Avoid overseas or unregulated sources to minimise counterfeit risk and protect your health. - Can Viagra be used with alcohol?
Limit alcohol intake while using Viagra. Small amounts are usually safe, but excessive drinking increases risk of side effects and may reduce the medicine’s effectiveness. - How quickly does Viagra work, and how long does it last?
It usually begins to work within 30–60 minutes, with effects lasting up to 4–6 hours. Sexual stimulation is required for an erection. - Who should not take Viagra?
People taking nitrates for chest pain, those with severe cardiac conditions or low blood pressure, and those who have had a recent stroke or heart attack without specialist clearance. Always consult your doctor for personalised advice.
For personalised advice or concerns, speak to your local Australian pharmacist or prescribing doctor. This guide is not a substitute for medical consultation.
