Complete BNF Safety Guidelines for Sildenafil Use
Critical Drug Interactions and Contraindications
The BNF highlights several critical contraindications for sildenafil that must be observed. Never combine sildenafil with nitrates such as GTN spray or isosorbide tablets, as this can cause dangerous blood pressure drops. Riociguat, used for pulmonary hypertension, is also contraindicated. Severe liver impairment, recent heart attack or stroke within six months, and hereditary retinal disorders are absolute contraindications listed in BNF guidelines.
Cardiovascular Precautions and Risk Assessment
The BNF emphasises careful cardiovascular assessment before prescribing sildenafil. Patients with unstable angina, severe heart failure, or uncontrolled blood pressure require specialist evaluation. Those taking alpha-blockers like doxazosin should start with lower sildenafil doses due to additive blood pressure effects. EverydayMeds clinicians follow these BNF protocols during consultation, ensuring appropriate risk stratification for each patient.
Dosage Guidelines and Administration Warnings
BNF dosing recommendations start at 50mg for most patients, adjustable to 25mg or 100mg based on response and tolerability. Maximum frequency is once per 24 hours. Fatty meals may delay onset, while alcohol can increase side effect risk. Generic sildenafil offers identical efficacy to Viagra at lower cost, with patients able to choose their preference during EverydayMeds checkout process.
Common Side Effects and Monitoring Requirements
The BNF documents frequent side effects including headache (affecting up to 16% of users), flushing, dyspepsia, and nasal congestion. Visual disturbances, though uncommon, require immediate medical attention. Priapism (prolonged erection over 4 hours) is a medical emergency. These side effects typically diminish with continued use, though persistent symptoms warrant dose adjustment or treatment review.
Special Populations and Dosage Adjustments
BNF guidelines recommend dose reductions for patients over 65, those with hepatic impairment, or severe renal dysfunction. CYP3A4 inhibitors like erythromycin or ketoconazole require sildenafil dose reduction due to increased drug levels. EverydayMeds assessments consider these factors, ensuring appropriate dosing based on individual patient characteristics and concurrent medications.
Value Comparison: Generic vs Branded Options
Generic sildenafil contains identical active ingredients to Viagra but costs significantly less. Both undergo identical regulatory approval processes and maintain equivalent safety profiles. EverydayMeds offers both options, allowing patients to choose based on preference and budget. Clinical efficacy remains unchanged regardless of brand selection, with BNF warnings applying equally to both formulations.
