Do nitrates cause erectile dysfunction? This is an important question for men prescribed these heart medications. Nitrates, including glyceryl trinitrate (GTN) and isosorbide mononitrate, are commonly used to manage angina and heart failure in the UK. Whilst erectile dysfunction is not typically listed as a direct side effect of nitrates in the British National Formulary, the relationship between these medications and sexual function is complex. Men taking nitrates often have underlying cardiovascular disease, which itself is strongly associated with erectile dysfunction through shared risk factors such as atherosclerosis and endothelial dysfunction. Understanding this connection is essential for safe management of both conditions.

What Are Nitrates and How Do They Work?

Nitrates are a class of medications commonly prescribed to manage angina (chest pain caused by reduced blood flow to the heart) and, in specific cases, heart failure. The most frequently prescribed nitrates in the UK include glyceryl trinitrate (GTN), isosorbide mononitrate, and isosorbide dinitrate. These medications are available in various formulations, including sublingual tablets, sprays, patches, and long-acting oral preparations.

Mechanism of action: Nitrates work by releasing nitric oxide in the body, which causes the smooth muscle in blood vessel walls to relax. This process, known as vasodilation, widens the blood vessels and reduces the workload on the heart. By dilating the coronary arteries, nitrates improve blood flow to the heart muscle, relieving angina symptoms. They also reduce venous return to the heart, which decreases the heart's oxygen demand.

The vasodilatory effects of nitrates are not limited to the heart. These medications cause systemic vasodilation, affecting blood vessels throughout the body. This widespread effect is why nitrates can cause common side effects such as headaches, dizziness, flushing, and postural hypotension. The drop in blood pressure that occurs with nitrate use is generally well-tolerated in most patients but can be enhanced when combined with alcohol or other blood pressure-lowering medications.

For patients with cardiovascular disease, nitrates play an important role in treatment. NICE guidelines recommend short-acting nitrates for immediate relief and prophylaxis of angina symptoms, while long-acting nitrates are typically used as second-line or add-on therapy for long-term control. In heart failure, nitrate-hydralazine combination is mainly used in specific scenarios, such as in patients of Black African or Caribbean origin or those who cannot tolerate ACE inhibitors or ARBs.

With long-acting nitrate preparations, a daily nitrate-free interval (typically overnight) is important to prevent nitrate tolerance, where the body becomes less responsive to the medication over time.

Do Nitrates Cause Erectile Dysfunction?

Erectile dysfunction (ED) is not commonly listed as an adverse effect of nitrates in UK product information or the British National Formulary (BNF). However, the relationship between nitrates and erectile function is complex and should be understood in the context of underlying cardiovascular disease.

Men who are prescribed nitrates typically have coronary artery disease or other cardiovascular conditions. Research indicates that erectile dysfunction and cardiovascular disease share common risk factors and pathophysiological mechanisms, including endothelial dysfunction, atherosclerosis, hypertension, diabetes, and smoking. Studies suggest that ED may actually be an early marker of cardiovascular disease, often preceding cardiac symptoms by several years.

The prevalence of erectile dysfunction is significantly higher in men with cardiovascular disease compared to the general population, affecting approximately 50% of men aged 40–70 with rates increasing with age and cardiovascular disease severity. This occurs because achieving and maintaining an erection requires adequate blood flow through healthy blood vessels. When atherosclerosis affects the smaller penile arteries, erectile function may be compromised before larger coronary vessels are significantly affected. Therefore, the erectile dysfunction experienced by men taking nitrates is more likely attributable to the underlying cardiovascular condition rather than the nitrate medication itself.

It is also worth noting that other cardiovascular medications, particularly certain beta-blockers and thiazide diuretics, have been more consistently associated with erectile dysfunction, though this varies between specific drugs within these classes. For example, some newer beta-blockers like nebivolol may have less impact on erectile function. Other medications that can contribute to ED include certain antidepressants (particularly SSRIs), antipsychotics, and medications affecting hormone levels.

If you are taking multiple cardiac medications and experiencing ED, it is important to discuss all your medications with your GP rather than assuming nitrates are the cause. Never stop taking any prescribed cardiac medication without medical advice, as this could worsen your cardiovascular condition.

Managing Erectile Dysfunction While Taking Nitrates

Managing erectile dysfunction in men taking nitrates requires careful consideration due to a critical drug interaction with phosphodiesterase type 5 (PDE5) inhibitors—the most common class of ED medications. PDE5 inhibitors include sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra), and avanafil (Spedra). These medications are absolutely contraindicated in patients taking any form of nitrate, whether regular or as-needed.

The combination of nitrates and PDE5 inhibitors can cause severe, potentially life-threatening hypotension (dangerously low blood pressure). Both drug classes work through nitric oxide pathways to cause vasodilation. When used together, their effects are synergistic rather than simply additive, leading to profound blood pressure drops that can result in cardiovascular collapse, syncope, or myocardial infarction. This interaction can occur even if nitrates are used infrequently, such as GTN spray for occasional angina episodes.

If you have taken a PDE5 inhibitor, you must not use nitrates for at least 24 hours after sildenafil or vardenafil, 48 hours after tadalafil, and 12 hours after avanafil. If you experience chest pain after taking a PDE5 inhibitor, do not use GTN—call 999 immediately and inform emergency services about the medication you have taken.

It's also important to avoid recreational nitrates ("poppers") if you are using PDE5 inhibitors, as these can cause the same dangerous interaction.

Alternative approaches to managing ED while taking nitrates include:

• Vacuum erection devices (VEDs): Mechanical devices that create an erection by drawing blood into the penis using negative pressure. These are safe to use with nitrates and may be available on NHS prescription for those meeting specific eligibility criteria under the Selected List Scheme.

• Intracavernosal injections: Medications such as alprostadil can be injected directly into the penis to produce an erection. This bypasses the nitric oxide pathway and does not interact with nitrates.

• Intraurethral therapy: Alprostadil can also be administered as a small pellet inserted into the urethra.

• Topical treatments: Alprostadil is available as a cream (Vitaros) that can be applied directly to the penis.

• Psychosexual counselling: Addressing psychological factors that may contribute to ED, available through NHS sexual health services.

• Lifestyle modifications: Smoking cessation, weight management, regular exercise, and moderating alcohol intake can all help improve erectile function.

Your GP or cardiologist may also review your cardiovascular medication regimen to determine if adjustments are possible. In some carefully selected patients with stable cardiovascular disease, it may be feasible to modify treatment to allow safe use of PDE5 inhibitors, but this decision must only be made by a specialist after thorough cardiovascular assessment.

When to Speak with Your GP About ED and Heart Medications

You should arrange to speak with your GP if you are experiencing erectile dysfunction, particularly if you are taking nitrates or other cardiovascular medications. Open communication about sexual health is essential for safe and effective management. Many men feel embarrassed discussing ED, but it is a common medical condition that your GP is well-equipped to address. Approximately 50% of men aged 40–70 experience some degree of erectile dysfunction, with the prevalence higher among those with cardiovascular disease.

Specific situations that warrant prompt GP consultation include:

• You are taking nitrates and considering using ED medications purchased online or obtained without prescription—this is extremely dangerous and potentially fatal.

• You have developed new or worsening erectile dysfunction, as this may indicate progression of cardiovascular disease or inadequate management of risk factors such as diabetes, hypertension, or high cholesterol.

• You are experiencing ED alongside other symptoms such as chest pain, breathlessness, or reduced exercise tolerance, which may suggest your cardiovascular condition requires reassessment. If you develop sudden severe chest pain or breathlessness, call 999 immediately.

• Your erectile dysfunction is affecting your mental health, relationships, or quality of life.

• You wish to discuss whether any of your medications might be contributing to ED and whether alternatives are available.

During your consultation, your GP will take a comprehensive history, including your cardiovascular condition, current medications (prescription, over-the-counter, and recreational), and other health factors. They may perform or arrange investigations such as blood pressure measurement, blood tests (including early-morning total testosterone on two occasions, HbA1c for diabetes, lipid profile, and possibly prolactin if testosterone is low), and cardiovascular risk assessment using tools such as QRISK3. NICE guidance recommends that ED should prompt evaluation of cardiovascular risk factors, as it may be an early warning sign of cardiovascular disease.

Your GP can refer you to specialist services if appropriate, including cardiology for medication review, urology for specialist ED management, or psychosexual services. They can also provide information about safe, non-pharmacological options for managing ED while taking nitrates.

If you experience any side effects from your medications, you can report them through the MHRA Yellow Card scheme, which helps monitor medication safety in the UK. Remember that your safety is paramount—never use PDE5 inhibitors if you are prescribed nitrates, and always inform any healthcare provider treating your ED about all your cardiac medications.

Frequently Asked Questions