Assurans (Sildenafil Citrate)

Assurans (Sildenafil Citrate): Comprehensive Patient Guide for Australia

Basic Product Information

Sildenafil citrate, commonly known as Assurans in Australia, is available by prescription for the treatment of pulmonary arterial hypertension (PAH) and, under other brands, for erectile dysfunction (ED). Assurans contains the same active ingredient as Viagra but is prescribed primarily for PAH rather than sexual health indications.

Mechanism of Action

For Patients: Sildenafil works by relaxing blood vessels, making it easier for your heart to pump blood through the lungs or, for ED, improving blood flow to specific areas. It helps lower the blood pressure in your lungs (PAH) or improve erectile function (ED).

For Specialists: Sildenafil is a selective inhibitor of phosphodiesterase type 5 (PDE5). By preventing the breakdown of cyclic guanosine monophosphate (cGMP), it causes vasodilation in the pulmonary vasculature (for PAH) and the corpus cavernosum (for ED), with minimal impact on systemic blood pressure at therapeutic doses.

Pharmacokinetics

• Absorption: Rapidly absorbed orally, peak plasma levels reached within 30–120 minutes (median ~60 min).
• Metabolism: Extensively metabolised in the liver via CYP3A4 (major) and CYP2C9 (minor) enzymes.
• Elimination: Mainly excreted as metabolites in the faeces (80%) and urine (13%).
• Duration of Action: Clinical effects last approximately 4–6 hours for PAH and 4 hours for ED; half-life ~4 hours.

Use in Everyday Life and Best Practices (Australian Context)

• Adults (for PAH): The typical dose is 20 mg three times daily, 6–8 hours apart, taken with or without food.
• Adults (for ED): As prescribed under alternative brands (Viagra, generic), generally 50 mg as needed, 1 hour before sexual activity.
• Consistency: Take the medicine at regular times each day (for PAH).
• Avoid Missing Doses: If you forget a dose, take it as soon as you remember unless it's nearly time for the next dose. Do not double up.
• Australian Patients: Ensure you use the product exactly as directed by your GP or specialist. Keep your prescriptions up to date, as sildenafil is not sold over the counter.

Dosing in the Morning vs Evening

• Morning Dosing: May offer improved adherence, as it's easier to remember morning medicines; may suit patients with stable daily schedules.
• Evening Dosing: For ED, take about 1 hour before sexual activity, regardless of the time of day; not linked to a specific daily schedule.
• Tips: For PAH, space doses as evenly as possible throughout the day (e.g., 8am, 2pm, 8pm). Set reminders if necessary.

Taking with Food or on an Empty Stomach

Sildenafil tablets can be taken with or without food. However, a high-fat meal (e.g., traditional pub meals or takeaways) may delay the medication’s onset of action. For quicker effect, especially in ED, take on an empty stomach or after a light meal.

• If you have a sensitive stomach, take with food to reduce the risk of mild stomach upset.
• Traditional Australian diets are compatible with sildenafil; avoid excessive fatty or oily meals for optimal effect if rapid onset is needed.

Interaction Warnings

Indications (Official and Off-Label)

Dosing According to Clinical Indication

Safety Profile/Side Effects

• Contact your GP if you notice chest pain, severe headache, visual or hearing loss, or an erection lasting longer than 4 hours (seek urgent help).
• Mild side effects usually improve as your body acclimatises; hydration and rest may help.

Guidelines for Proper Use in Australia

• Always use sildenafil as prescribed by your GP or specialist, and attend regular follow-ups.
• Report all medications and supplements you use to your pharmacist.
• Avoid buying from unlicensed websites; use Australian PBS or TGA-authorised pharmacies.
• Store in a dry place, below 30°C, away from children.
• Dispose of leftover tablets responsibly—return unused medicines to your pharmacy.
• If travelling, carry your prescription, especially for interstate or international travel.

Alternative Treatment Options

• Tadalafil (Cialis, Adcirca)
  • Pros: Longer-acting, once-daily dosing for PAH or ED; requires less planning.
  • Cons: More expensive, similar interaction profile, not suitable if you experience side effects to sildenafil.
• Vardenafil (Levitra)
  • Pros: Rapid onset for ED; alternative if sildenafil is not well-tolerated.
  • Cons: Shorter action; not funded for PAH.
• Riociguat (for PAH)
  • Pros: Alternative for PAH; PBS listed for certain forms.
  • Cons: Specialist access needed; more monitoring required.
• Other non-pharmacological options include device-assisted therapies or supportive counselling for ED.

Legal, Registration, and Reimbursement Status in Australia

• Registered by the Therapeutic Goods Administration (TGA).
• Prescription-only (Schedule 4 medicine).
• Available via the Pharmaceutical Benefits Scheme (PBS) for PAH and some ED indications with strict criteria.
• Private prescription options exist for other uses, but not reimbursed by Medicare unless criteria are met.
• Always consult a licensed Australian healthcare professional before starting treatment.

Latest Research and Clinical Guidance (2022–2025)

• Recent RCTs confirm continued benefit for PAH and functional improvements; no new safety concerns (Lancet Respir Med, 2023).
• Updated 2024 guidelines from the Thoracic Society of Australia and New Zealand recommend sildenafil as a first-line therapy for selected PAH patients.
• Long-term real-world evidence supports safety and efficacy in both PAH and ED (Med J Aust, 2022–2024).
• No significant new contraindications identified, but TGA continues to monitor for rare cardiovascular or vision events.

Availability, Pack Sizes, and Delivery (Australia)

FAQ

• Can I buy Assurans over the counter in Australia?
  No. It is only available on prescription from a GP or specialist.
• What should I do if I miss a dose?
  Take as soon as possible unless it’s nearly time for your next dose. Do not double-dose.
• Can I use Assurans for erectile dysfunction?
  Assurans (20 mg) is designed for PAH. For ED, other brands (Viagra, generics) and doses are usually prescribed. Speak with your doctor for the correct option.
• Is it safe to take this with my heart medications?
  Use with caution. Never combine sildenafil with nitrates or certain heart drugs. Always inform your prescriber about all your medications.
• Is Assurans reimbursed by the PBS?
  Yes, for PAH and sometimes for ED if strict PBS criteria are met. Private options exist for other indications.