Sildenafil citrate, widely recognized by the brand name Viagra, is a medication approved for the management of erectile dysfunction (ED) in men. Its primary medical application is to help achieve and sustain an erection by increasing blood flow to the penis. The medication functions by targeting a specific enzyme and requires sexual stimulation to work.
Sildenafil does not increase sexual desire and only facilitates a physical response in the presence of sexual arousal. The typical dosage is taken 30 to 60 minutes before planned sexual activity.
The Theory of Sildenafil in Female Sexual Function
The scientific rationale for exploring sildenafil’s use in women is based on its mechanism of action. Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor that blocks an enzyme responsible for restricting blood flow. By blocking PDE5, sildenafil causes vasodilation (the widening of blood vessels), which increases blood flow.
The theory is that this effect is not limited to male anatomy, as the female genital region contains similar vascular tissue. Researchers hypothesized that increasing blood flow to the clitoris and labia could enhance the physical aspects of female sexual arousal, such as lubrication and sensation.
The proposed benefit focuses on female sexual arousal disorder, an inability to attain or maintain the physical response of excitement. This is distinct from hypoactive sexual desire disorder (HSDD), which is characterized by low sexual interest, as sildenafil addresses blood flow rather than desire.
Clinical Evidence and Efficacy
Despite the plausible theory, clinical investigations into sildenafil’s effectiveness for female sexual dysfunction have yielded inconsistent results. Studies assessing whether the drug can improve sexual satisfaction, arousal, or orgasm in women have not demonstrated a consistent benefit compared to a placebo.
Consequently, the U.S. Food and Drug Administration (FDA) has not approved sildenafil for any form of female sexual dysfunction. The complexity of female sexual response, involving an interplay of hormonal, psychological, and physiological factors, is believed to be why a drug focused on blood flow has not been a straightforward solution.
While not approved for women, some healthcare providers may prescribe sildenafil “off-label.” This practice means a doctor prescribes a drug for a condition other than its approved use, based on their professional judgment rather than conclusive clinical trial data.
Potential Side Effects and Safety Considerations
When studied in women, sildenafil’s side effects have been similar to those in men, stemming from its effect of widening blood vessels throughout the body. Common adverse effects are typically mild and transient, and can include:
- Headache
- Facial flushing
- Nasal congestion
- Nausea
- Visual disturbances, such as a temporary blue tinge to vision
- Indigestion or an upset stomach
Specific safety warnings are also relevant. Sildenafil is not recommended for individuals with certain cardiovascular conditions due to its effects on blood pressure. Its safety during pregnancy or while breastfeeding has not been established and it should be avoided in these circumstances. It is important to discuss a full medical history with a healthcare provider before considering an off-label prescription.
Approved Treatments for Female Sexual Dysfunction
Given that sildenafil is not an approved treatment, it is useful to know which medications have received FDA approval for female sexual dysfunction. These approved treatments function very differently, targeting brain chemistry rather than the direct blood flow mechanism of sildenafil.
One approved medication is flibanserin (Addyi), a daily pill for premenopausal women diagnosed with hypoactive sexual desire disorder (HSDD). Flibanserin works on neurotransmitters in the brain, like serotonin and dopamine, to help restore a balance linked to sexual desire. It requires weeks of consistent use to see an effect.
Another FDA-approved option is bremelanotide (Vyleesi), an injectable medication self-administered as needed before sexual activity. It is also approved for premenopausal women with HSDD and works by activating melanocortin receptors in the brain, which are believed to play a role in modulating sexual desire.