Sildenafil citrate, widely known as Viagra, is a prescription medication licensed in the UK for erectile dysfunction in men and pulmonary arterial hypertension. Whilst it works by increasing blood flow through inhibition of the PDE5 enzyme, sildenafil is not licensed by the MHRA for use in women for sexual dysfunction. Despite theoretical benefits based on enhanced genital blood flow, clinical evidence for efficacy in women remains limited and inconsistent. Female sexual dysfunction involves complex psychological, hormonal, and vascular factors that cannot be addressed by simply increasing blood flow. This article examines the evidence, risks, and licensed alternatives for women experiencing sexual health concerns.

What Is Sildenafil Citrate and How Does It Work?

Sildenafil citrate is a prescription medication licensed in the UK primarily for the treatment of erectile dysfunction (ED) in men and pulmonary arterial hypertension. Marketed under brand names such as Viagra, Revatio, and various generic formulations, sildenafil belongs to a class of drugs called phosphodiesterase type 5 (PDE5) inhibitors.

The mechanism of action centres on the relaxation of smooth muscle tissue within blood vessels. Sildenafil works by inhibiting the PDE5 enzyme, which normally breaks down cyclic guanosine monophosphate (cGMP). When PDE5 is blocked, cGMP levels increase, leading to vasodilation—widening of blood vessels—and improved blood flow to specific tissues. In men with ED, this enhanced blood flow to the penis facilitates the achievement and maintenance of an erection in response to sexual stimulation (the medication is not effective without sexual arousal).

In women, the physiological rationale for using sildenafil is based on a similar principle: increased genital blood flow might theoretically improve arousal, lubrication, and sensation. Female sexual arousal involves complex vascular changes in the clitoris and vaginal tissues, and some researchers have hypothesised that enhanced blood flow could address certain aspects of female sexual dysfunction (FSD). However, it is crucial to note that sildenafil is not licensed by the MHRA for use in women for sexual dysfunction. Any such use would be off-label and should only be considered under specialist clinical supervision.

Female sexual response involves intricate psychological, hormonal, neurological, and vascular factors, and simply increasing blood flow does not address the multifaceted nature of FSD. While the drug's pharmacology is well understood in male physiology, evidence for its efficacy in women remains limited and inconsistent, with some modest benefit shown only in specific situations such as SSRI-induced sexual dysfunction.

Licensed Treatments for Female Sexual Dysfunction in the UK

Female sexual dysfunction encompasses a range of concerns including reduced libido, arousal difficulties, orgasmic dysfunction, and pain during intercourse (dyspareunia). Unlike male ED, where several licensed pharmacological options exist, the treatment landscape for FSD in the UK is considerably more limited.

Currently, there are no medications specifically licensed by the MHRA for global female sexual dysfunction or hypoactive sexual desire disorder. Medications approved in some other countries (such as flibanserin and bremelanotide) are not licensed in the UK. However, there are licensed treatments for specific aspects of sexual dysfunction, particularly those related to genitourinary syndrome of menopause:

• Vaginal oestrogens (creams, pessaries, rings) are licensed for vulvovaginal atrophy and can significantly improve dyspareunia and vaginal comfort

• Where locally available and commissioned, prasterone (vaginal DHEA) and ospemifene (an oral selective oestrogen receptor modulator) may be options for postmenopausal vulvovaginal atrophy affecting sexual function

NICE guidance (CKS: Sexual problems in women; NG23: Menopause) emphasises a holistic, individualised approach to managing FSD. Initial management typically involves:

• Detailed assessment of physical, psychological, and relational factors

• Lifestyle modifications including stress reduction, improved sleep, and regular physical activity

• Psychological interventions such as cognitive behavioural therapy (CBT) or psychosexual counselling

• Treatment of underlying conditions (e.g., managing diabetes, adjusting medications causing sexual side effects)

• Lubricants and moisturisers for symptomatic relief of vaginal dryness

For postmenopausal women, hormone replacement therapy (HRT) may improve sexual function indirectly by addressing symptoms like hot flushes, mood changes, and vaginal atrophy. According to British Menopause Society guidance, testosterone therapy may be considered off-label for postmenopausal women with hypoactive sexual desire disorder after appropriate biopsychosocial assessment, with informed consent and monitoring. Availability varies by local formularies and is not widely accessible on the NHS.

The limited range of licensed pharmacological treatments underscores the importance of comprehensive assessment and addressing underlying causes rather than seeking a simple pharmaceutical solution.

Potential Risks of Using Sildenafil Off-Label in Women

Despite the lack of MHRA licensing for female sexual dysfunction, some women may obtain sildenafil through private prescriptions or online sources, hoping it might improve their sexual response. Using sildenafil off-label in women carries several important risks and considerations that should not be overlooked.

Limited evidence of efficacy: Clinical trials investigating sildenafil for FSD have produced inconsistent and largely disappointing results. Systematic reviews have found no consistent benefit for arousal, orgasm, or overall sexual satisfaction in most women. The few studies showing modest improvements were often in highly selected populations (e.g., women with sexual dysfunction secondary to antidepressant use) and did not demonstrate clinically meaningful changes for most participants.

Contraindications: Sildenafil must not be used by women who:

• Take nitrate medications (including nicorandil) for angina or heart conditions

• Take riociguat for pulmonary hypertension

• Have had a recent serious cardiovascular event (heart attack, stroke, severe arrhythmia)

• Have severe hypotension or uncontrolled hypertension

Adverse effects: Sildenafil can cause side effects in women similar to those experienced by men, including:

• Headaches (the most commonly reported adverse effect)

• Facial flushing and warmth

• Nasal congestion

• Visual disturbances including blue-tinted vision or increased light sensitivity

• Dyspepsia (indigestion) and gastrointestinal discomfort

• Dizziness and lightheadedness, particularly with postural changes

Serious adverse effects requiring urgent medical attention include:

• Sudden vision or hearing loss

• Chest pain or shortness of breath

• Fainting or collapse

• Prolonged, painful erection of the clitoris

• Severe allergic reactions

Drug interactions: Sildenafil is metabolised by liver enzymes (CYP3A4) and can interact with numerous medications. Particular caution is needed with:

• Strong CYP3A4 inhibitors (e.g., ritonavir, cobicistat, ketoconazole, clarithromycin) which can significantly increase sildenafil levels

• CYP3A4 inducers (e.g., rifampicin, carbamazepine) which may reduce effectiveness

• Multiple antihypertensive medications, potentially causing additive blood pressure lowering

Lack of safety data: Long-term safety data for sildenafil use in women is extremely limited. There is insufficient evidence regarding its safety in pregnancy, breastfeeding, or in women with specific gynaecological conditions. Women who are pregnant, planning pregnancy, or breastfeeding should not use sildenafil for sexual dysfunction.

Psychological impact: Relying on medication without addressing underlying psychological, relational, or medical factors may delay appropriate treatment and potentially worsen distress related to sexual function.

Sourcing concerns: Women should avoid obtaining sildenafil from unregulated online sources. If prescribed, it should only be through GPhC-registered pharmacies and after appropriate clinical assessment. Suspected adverse effects should be reported via the MHRA Yellow Card Scheme (yellowcard.mhra.gov.uk).

When to Speak to Your GP About Sexual Health Concerns

Sexual health concerns are common and can significantly impact quality of life and relationships, yet many women feel uncomfortable discussing these issues with healthcare professionals. It is important to recognise that sexual dysfunction is a legitimate medical concern that deserves professional attention and support.

You should consider speaking to your GP if you experience:

• Persistent or recurrent difficulties with sexual desire, arousal, orgasm, or pain during intercourse that cause personal distress

• Sudden changes in sexual function, particularly if associated with new medications, medical conditions, or life events

• Pain during intercourse (dyspareunia), which may indicate conditions such as endometriosis, pelvic inflammatory disease, vaginal atrophy, or vulvodynia

• Vaginal dryness, itching, or discomfort, especially after menopause

• Relationship difficulties related to sexual concerns

• Psychological distress including anxiety, low mood, or reduced self-esteem related to sexual function

Seek urgent medical attention for:

• Postmenopausal bleeding (requires urgent 2-week-wait referral to exclude cancer)

• Persistent postcoital bleeding

• Severe pelvic pain with fever (possible pelvic inflammatory disease)

• New neurological symptoms affecting genital sensation or function

• Heavy unexplained vaginal bleeding

• Concerns about sexual assault (urgent safeguarding and Sexual Assault Referral Centre support)

Your GP can provide:

• A comprehensive assessment including medical history, medication review, and physical examination if appropriate

• Investigation of underlying causes such as thyroid dysfunction, diabetes, cardiovascular disease, or neurological conditions

• Review of current medications that may contribute to sexual dysfunction (e.g., SSRIs, beta-blockers)

• Referral to specialists including gynaecologists, endocrinologists, or psychosexual therapists as needed

• Evidence-based treatment options tailored to your specific situation

• Information and reassurance about normal sexual function and age-related changes

Many GP practices now have clinicians with special interests in women's health or sexual medicine who can provide particularly informed support. NHS sexual health clinics also offer confidential advice and may be an alternative point of access if you prefer.

Remember: Sexual health is an integral part of overall wellbeing. Seeking help is a positive step towards understanding and addressing your concerns. Sildenafil is not licensed for female sexual dysfunction in the UK, and evidence of benefit is inconsistent and insufficient for most women. Self-medicating with unlicensed treatments may delay appropriate care and carry unnecessary risks. A thorough assessment by a healthcare professional is essential to identify the underlying causes and develop an effective, safe treatment plan tailored to your individual needs.

Frequently Asked Questions