Sildenafil, widely recognised for treating erectile dysfunction in men, is not licensed in the UK for female sexual dysfunction. Women considering this medication should understand that any use would be off-label, requiring careful medical supervision and a valid prescription. The evidence supporting sildenafil for women remains limited and inconsistent, with most large trials failing to demonstrate significant clinical benefit. Female sexual dysfunction is complex, involving psychological, hormonal, and relational factors alongside physical components. This article examines the current evidence, potential dosing considerations, risks, and alternative treatments available through the NHS for women experiencing sexual health concerns.

Is Sildenafil Licensed for Use in Women in the UK?

Sildenafil is not currently licensed by the Medicines and Healthcare products Regulatory Agency (MHRA) for the treatment of sexual dysfunction in women in the UK. The medication holds marketing authorisation exclusively for erectile dysfunction in men and pulmonary arterial hypertension in both sexes. This means that any use of sildenafil for female sexual dysfunction would be considered off-label prescribing.

It's important to note that Viagra Connect (the pharmacy-only version of sildenafil) is authorised for adult men only. Women would require a prescription for sildenafil, which would always be off-label for sexual dysfunction.

Off-label prescribing is legal and sometimes clinically appropriate when a healthcare professional believes the potential benefits outweigh the risks for an individual patient. However, it requires careful consideration, informed consent, and thorough documentation. The prescriber assumes greater responsibility when using a medicine outside its licensed indications, as the manufacturer's safety data and efficacy evidence may be limited for that particular use.

In the UK, NICE guidance does not currently recommend sildenafil for female sexual dysfunction, reflecting the lack of robust evidence supporting its routine use in women. The General Medical Council (GMC) advises that off-label prescribing should only occur when there is sufficient evidence or experience to demonstrate safety and efficacy, and when licensed alternatives have been considered. Women considering sildenafil should have a comprehensive discussion with their GP or specialist about the evidence base, potential risks, and alternative treatment options.

It is important to note that sildenafil obtained without prescription—such as through unregulated online sources—may be counterfeit, contaminated, or incorrectly dosed, posing significant health risks. Any woman considering sildenafil should only do so under proper medical supervision with a valid prescription from a registered healthcare professional, and should use UK-registered pharmacies (those displaying the General Pharmaceutical Council registration logo) if obtaining medicines online.

What Does the Evidence Say About Sildenafil for Women?

The evidence base for sildenafil in treating female sexual dysfunction remains limited and inconsistent. Sildenafil works by inhibiting phosphodiesterase type 5 (PDE5), an enzyme that breaks down cyclic guanosine monophosphate (cGMP). In men, this increases blood flow to the penis, facilitating erections. The theoretical rationale for use in women is that enhanced genital blood flow might improve arousal and sexual response.

Several clinical trials have investigated sildenafil for female sexual arousal disorder and other forms of sexual dysfunction, but results have been mixed. Some small studies suggested modest improvements in physiological arousal measures, such as vaginal blood flow and lubrication. However, larger, well-designed randomised controlled trials have generally failed to demonstrate significant clinical benefit over placebo in terms of subjective sexual satisfaction, desire, or orgasm.

A key challenge is that female sexual dysfunction is multifactorial, involving psychological, relational, hormonal, and social factors alongside physiological components. Unlike erectile dysfunction, where the primary issue is often vascular, female sexual concerns frequently require a more holistic approach. Sildenafil's mechanism addresses only the vascular element, which may explain why physiological changes do not always translate into meaningful improvements in sexual experience.

Certain subgroups may respond differently. For instance, some research has explored sildenafil in women taking selective serotonin reuptake inhibitors (SSRIs), as these antidepressants commonly cause sexual side effects. Results have been variable, with some studies showing modest benefit and others finding no significant effect. The Cochrane Collaboration has noted insufficient evidence to support routine use of PDE5 inhibitors like sildenafil for female sexual dysfunction, emphasising the need for further high-quality research before any firm recommendations can be made.

Potential Dosing Considerations if Prescribed Off-Label

If a healthcare professional decides to prescribe sildenafil off-label for a woman, there is no established standard dose for female sexual dysfunction, as the medication lacks licensing for this indication. In clinical trials that have investigated sildenafil in women, doses have typically ranged from 25 mg to 100 mg, taken approximately one hour before anticipated sexual activity—similar to the dosing regimen used in men with erectile dysfunction.

The most commonly studied dose in research settings has been 50 mg, which represents a middle-range starting point. Some clinicians may begin with a lower dose of 25 mg to assess tolerability, particularly in women who may be more susceptible to side effects or who are taking other medications. According to UK SmPC guidance, a starting dose of 25 mg should be considered for elderly patients, those with severe renal impairment (creatinine clearance <30 mL/min), or hepatic impairment.

The dose may be adjusted based on individual response and tolerability, but should not exceed 100 mg in a 24-hour period, and sildenafil should not be taken more than once daily. Women taking potent CYP3A4 inhibitors (such as ritonavir, ketoconazole, or clarithromycin) should start at 25 mg, and with ritonavir specifically, should not exceed 25 mg in 48 hours. Grapefruit juice should be avoided as it may increase sildenafil levels.

It is crucial to understand that sildenafil is not a daily medication for sexual dysfunction and should not be taken regularly without specific medical advice. The drug's effects are temporary, lasting approximately 4–6 hours, and it requires sexual stimulation to be effective—it does not spontaneously increase desire or arousal.

Sildenafil is absolutely contraindicated with nitrates (with at least 24 hours separation required) and riociguat (a medication for pulmonary hypertension). Women already taking sildenafil for pulmonary arterial hypertension must not take additional doses for sexual dysfunction. Any woman prescribed sildenafil off-label should have a thorough medical assessment, including review of current medications, to identify potential drug interactions.

Risks and Side Effects of Sildenafil in Women

Sildenafil can cause a range of side effects in women, similar to those experienced by men. The most commonly reported adverse effects include:

• Headache – the most frequent side effect, occurring in up to 16% of users in some studies

• Facial flushing – due to vasodilation

• Nasal congestion – resulting from increased blood flow to nasal mucosa

• Dyspepsia and gastrointestinal discomfort – including nausea and indigestion

• Visual disturbances – such as blurred vision, increased sensitivity to light, or a blue tinge to vision (due to mild PDE6 inhibition in the retina)

• Dizziness – particularly when standing quickly, due to blood pressure effects

More serious but rare adverse effects include cardiovascular events. Sildenafil causes vasodilation and can lower blood pressure, which may be problematic in women with pre-existing cardiovascular disease, hypotension (blood pressure below 90/50 mmHg), or those taking antihypertensive medications. Caution is advised in those with recent myocardial infarction, stroke, or unstable angina. There have been isolated reports of myocardial infarction and stroke associated with sildenafil use, though causality is difficult to establish.

Rare but serious eye and ear complications include non-arteritic anterior ischaemic optic neuropathy (NAION) and sudden hearing loss. Anyone experiencing sudden vision or hearing changes should stop taking sildenafil immediately and seek urgent medical attention.

Contraindications include concurrent use of nitrates (such as glyceryl trinitrate for angina), as this combination can cause life-threatening hypotension. Sildenafil must not be taken within 24 hours of using any nitrate medication. It is also contraindicated with riociguat. Women taking alpha-blockers, certain antifungals, or HIV protease inhibitors should also exercise caution due to potential drug interactions.

There is limited safety data regarding sildenafil use during pregnancy or breastfeeding. While sildenafil has been studied for pulmonary hypertension in pregnancy, its use for sexual dysfunction in pregnant or breastfeeding women is not recommended due to insufficient evidence. Women of childbearing potential should discuss contraception with their healthcare provider.

Patients should not drive or operate machinery if experiencing dizziness or visual disturbances after taking sildenafil.

Any woman experiencing chest pain, severe headache, sudden vision or hearing loss, or signs of an allergic reaction (rash, swelling, difficulty breathing) after taking sildenafil should call 999 or go to A&E immediately. Suspected adverse reactions can be reported via the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk).

Alternative Treatments for Female Sexual Dysfunction

Female sexual dysfunction is complex and multifaceted, often requiring a holistic, individualised approach rather than a single pharmacological intervention. NICE guidance emphasises the importance of addressing psychological, relational, and physical factors contributing to sexual concerns.

Psychological and relationship-based interventions are considered first-line treatments for many forms of female sexual dysfunction. Cognitive behavioural therapy (CBT) and psychosexual counselling can address anxiety, negative thought patterns, and relationship issues that impact sexual function. These interventions are available through some NHS sexual health clinics, specialist psychosexual services, or private practitioners accredited by organisations such as the College of Sexual and Relationship Therapists (COSRT).

Hormonal treatments may be appropriate for certain women, particularly those experiencing sexual dysfunction related to menopause. Vaginal oestrogen (creams, pessaries, or rings) can effectively treat vaginal dryness and atrophy, improving comfort during intercourse. For postmenopausal women with hypoactive sexual desire disorder, NICE guideline NG23 notes that testosterone therapy may be considered off-label when hormone replacement therapy alone is not effective. Any hormonal treatment requires careful assessment of risks and benefits, particularly regarding cardiovascular and breast cancer risk.

Flibanserin and bremelanotide are medications licensed in some countries (including the USA) for premenopausal women with hypoactive sexual desire disorder, but neither is currently available in the UK. These drugs work on neurotransmitter systems rather than vascular mechanisms, but have shown only modest efficacy with significant side effects.

Non-pharmacological approaches include:

• Pelvic floor physiotherapy – particularly beneficial for women with pelvic pain or dyspareunia

• Vaginal lubricants and moisturisers – for managing dryness and discomfort

• Lifestyle modifications – addressing factors such as stress, fatigue, alcohol consumption, and relationship communication

• Treatment of underlying conditions – such as depression, anxiety, or chronic pain that may impact sexual function

Where sexual dysfunction appears to be medication-induced (particularly with antidepressants), a GP or psychiatrist review may identify alternative treatments with fewer sexual side effects.

Women experiencing persistent sexual concerns should consult their GP for a comprehensive assessment. This should include discussion of medical history, medications, relationship factors, and psychological wellbeing. Referral to specialist psychosexual services, gynaecology, or endocrinology may be appropriate depending on the underlying causes identified. The NHS website offers information on sexual problems in women and available services. A multidisciplinary approach often yields the best outcomes for female sexual dysfunction.

Frequently Asked Questions