Sildenafil and Amitriptyline: Can You Take Them Together?

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Key takeaways

• Sildenafil and amitriptyline can usually be taken together safely with no major direct interaction.
• Both medicines can lower blood pressure, so your prescriber checks for dizziness risk and may start a lower dose.
• Amitriptyline itself can cause erectile difficulties in some men; discuss this with your GP if it's a concern.
• Always declare all your medicines during your consultation so your prescriber can review them together.
• Stand up slowly and avoid heavy alcohol to reduce the risk of dizziness when taking both medicines.

What is sildenafil and amitriptyline used for?

Sildenafil is a medicine used to treat erectile dysfunction (ED). It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing blood vessels in the penis, allowing increased blood flow when you are sexually aroused [3]. Sildenafil is the active ingredient in Viagra and is available in doses of 25mg, 50mg, and 100mg. You typically take it about one hour before sexual activity, and it can help you get and maintain an erection suitable for sex. Sexual stimulation is still needed for the medicine to work.

Amitriptyline is a tricyclic antidepressant that is commonly prescribed for several conditions, including depression, nerve pain (neuropathic pain), and the prevention of migraines. It works by affecting certain chemical messengers in the brain and nervous system. Amitriptyline is usually taken once daily, often at bedtime because it can cause drowsiness. The dose varies depending on the condition being treated, and it may take several weeks to feel the full benefit when used for depression or pain relief.

Is there an interaction between sildenafil and amitriptyline?

There is no major direct drug interaction between sildenafil and amitriptyline that would make them unsafe to take together [3][12]. Neither medicine significantly affects how the other is processed in your body, and they do not combine to cause dangerous effects in the way that sildenafil does with nitrates, for example. This means that your prescriber can consider both medicines together during your consultation, and many men safely use both.

However, there are some important considerations. Both sildenafil and amitriptyline can lower blood pressure, and taking them together may increase the chance of feeling dizzy or light-headed, especially when you stand up quickly. Amitriptyline itself can also cause erectile difficulties as a side effect in some men, which is one reason you might be seeking ED treatment in the first place. Your prescriber will take all of these factors into account when deciding whether sildenafil is suitable for you and which dose to start with.

How the interaction works in plain English

Sildenafil works by widening blood vessels, which lowers blood pressure slightly as a normal part of its action. Amitriptyline can also lower blood pressure, particularly when you move from sitting or lying down to standing (called postural hypotension). When you take both medicines, these blood-pressure-lowering effects can add together, making dizziness more likely. This does not mean the combination is dangerous for most people, but it does mean your prescriber will check your blood pressure history, ask about any dizziness you have experienced, and may start you on a lower dose of sildenafil to minimise the risk.

At a glance

What does your prescriber check before prescribing sildenafil and amitriptyline together?

When you request sildenafil through an online consultation at Cured Pharmacy, the UK-registered prescriber will review your full medical history and all the medicines you are currently taking, including amitriptyline. They will check your cardiovascular health, including any history of heart disease, stroke, high or low blood pressure, and whether you have experienced dizziness or fainting. They will also ask about other medicines that could interact with sildenafil, such as nitrates, alpha-blockers, or other blood-pressure treatments [2][3].

The prescriber will want to know why you are taking amitriptyline, how long you have been on it, what dose you take, and whether you have noticed any side effects, including sexual difficulties. If your erectile dysfunction started or worsened after beginning amitriptyline, your prescriber may suggest discussing this with your GP, as switching to a different medicine for your underlying condition might help. The consultation will also cover whether you have any conditions that make PDE5 inhibitors unsuitable, such as recent heart attack or stroke, severe heart failure, or a history of sudden vision loss.

Practical advice for taking sildenafil with amitriptyline

If your prescriber approves sildenafil while you are taking amitriptyline, there are some practical steps you can take to use it safely and effectively. Take sildenafil about one hour before you plan to have sex, on an empty stomach or after a light meal, as a heavy or high-fat meal can delay how quickly it works [3]. Avoid drinking large amounts of alcohol, as this can make erectile dysfunction worse and increase the risk of dizziness when combined with both medicines.

Be aware of how you feel when you stand up, especially in the first few hours after taking sildenafil. If you feel dizzy or light-headed, sit or lie down until it passes. Make sure you are well hydrated, and avoid suddenly jumping up from a sitting or lying position. If you experience chest pain during or after sex, stop the activity and seek urgent medical help—do not take any nitrate medicine (such as GTN spray) if you have used sildenafil in the past 24 hours, as this combination can cause a dangerous drop in blood pressure.

Do not adjust the dose of either medicine yourself. If sildenafil does not work as well as you hoped, or if you experience side effects, contact your prescriber or pharmacist for advice. Similarly, do not stop taking amitriptyline without speaking to the doctor who prescribed it, as stopping suddenly can cause withdrawal symptoms.

When to speak to your GP

If you have not already discussed your erectile dysfunction with your GP, it is a good idea to do so, especially if it is a new problem. ED can be an early warning sign of cardiovascular disease or diabetes, and your GP can arrange tests and review your overall health [1][2]. If you think amitriptyline might be contributing to your ED, your GP may be able to adjust the dose or consider an alternative treatment for your depression, pain, or migraines. Never stop or change a prescribed medicine without professional advice.

Are there any warning signs to watch for with sildenafil and amitriptyline?

Most men tolerate sildenafil well, even when taking amitriptyline, but you should be aware of some warning signs that need prompt attention. Common side effects of sildenafil include headache, facial flushing, indigestion, and a stuffy nose; these are usually mild and short-lived [3]. Dizziness or light-headedness can occur, particularly if you are also taking amitriptyline or other medicines that lower blood pressure.

Seek urgent medical help if you experience an erection that lasts longer than four hours (priapism), as this can damage the penis if not treated quickly. Sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness), are rare but serious side effects that require immediate medical attention [3]. If you develop chest pain during or after sexual activity, stop and seek help straight away—do not take nitrate medicines if you have used sildenafil within the past 24 hours.

If you notice worsening dizziness, fainting, or a very slow or fast heartbeat, contact your GP or call NHS 111 for advice. These symptoms could indicate that the combination of medicines is affecting your blood pressure or heart rhythm more than expected, and your treatment may need to be reviewed.

Other ED treatment options and how amitriptyline affects them

If sildenafil is not suitable or does not work well for you while taking amitriptyline, there are other ED treatments available. Tadalafil (Cialis) is another PDE5 inhibitor that works in a similar way to sildenafil but lasts much longer—up to 36 hours—giving you more flexibility [4]. Vardenafil (Levitra) and avanafil (Spedra) are also PDE5 inhibitors with slightly different timing and duration [5][6]. The same considerations about blood pressure apply to all PDE5 inhibitors when taken with amitriptyline.

For men who cannot use PDE5 inhibitors, or for whom they are not effective, other options include alprostadil, which can be given as a cream applied to the tip of the penis (Vitaros) or as an injection into the side of the penis (Caverject) [7]. Vacuum erection devices and penile implants are non-drug options that may be considered in some cases. Your prescriber or GP can discuss these alternatives with you.

It is also worth exploring whether the underlying cause of your ED can be addressed. If amitriptyline is contributing to the problem, your GP may be able to switch you to a different medicine. Lifestyle changes such as losing weight if needed, increasing physical activity, stopping smoking, and reducing alcohol intake can all improve erectile function [1][2]. Treating conditions such as diabetes, high blood pressure, and high cholesterol also helps.

How Cured Pharmacy can help with sildenafil and amitriptyline

Cured Pharmacy is a GPhC-registered online pharmacy offering a confidential, convenient service for ED treatment. After you complete an online consultation, a UK-registered prescriber will review your answers, including all your current medicines such as amitriptyline, and decide whether sildenafil or another ED treatment is safe and suitable for you. If approved, your medicine is dispensed by our pharmacy team and delivered discreetly to your door. You can choose from a range of ED treatments, including sildenafil from £0.45 per tablet (or £0.36 with first-order code Ednew), and our pharmacists are available if you have any questions about taking your treatment safely alongside other medicines.

When to get urgent help

• Erection lasting more than 4 hours (priapism) – go to A&E immediately
• Sudden loss of vision in one or both eyes – seek urgent medical help
• Chest pain during or after sex – stop activity, call 999, do not take nitrates
• Sudden loss of hearing or ringing in the ears with dizziness – contact your GP urgently
• Severe dizziness, fainting, or very slow/fast heartbeat – call NHS 111 or your GP

Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.