There are a number of different treatments available for erectile dysfunction. In recent years these have become more effective while offering minimal side effects for the vast majority of men who use them. As is the case with any medication, however, side effects do exist and in rare cases these can be quite severe. It is therefore important that you understand what they are before starting treatment. Cialis, and its generic version tadalafil, are generally well tolerated by most when directions are properly followed.

If you experience any serious side effects while taking this medication, including signs of an allergic reaction, discontinue use and seek immediate medical attention. This includes swelling of the mouth, lips, face or throat alongside rashes and hives.

Trials for Cialis

Trials for Cialis and tadalafil have been very positive, even in the most severe cases. Many preferred it to other erectile dysfunction treatments, including one trial in 2003 (when the medication was launched) that found over 90% of patients preferred it compared to other PDE-5 inhibitors.

Frequency of Cialis side effects

As previously mentioned, frequent side effects for Cialis and tadalafil are relatively mild and will likely fade quickly after use. Most will notice no side effects, particularly when the right dosage has been prescribed, which might take some experimentation to begin with. It should be noted that this is the case for all forms of PDE-5 inhibitor treatments, including Viagra and Spedra .

Common side effects, affecting one to ten in every 100 patients, include: headaches, back aches, muscle pain, discomfort in arms and legs, flushing, nasal congestion and digestive issues.

The less common side effects associated with Cialis and tadalafil can be more severe. For example, those that occur in one to ten in every 1,000 patients include: dizziness, stomach pain, nausea, vomiting, reflux, vision issues, eye pain, problems breathing, blood in urine, persistent erections, pounding heartbeat, rapid heart rate, hypertension, low blood pressure, nose bleeds, tinnitus, swelling of the hands, feet or ankles and fatigue.

Other side effects are described as rare, which means it is highly unlikely that they will occur. While that is the case, it is still important that you understand what these are so you can recognise them if they do. These are described as those that occur in one to ten of every 10,000 patients and include: fainting, seizures and passing memory loss, swelling of the eyelids, red eyes, sudden decrease or loss of hearing, hives, penile bleeding, presence of blood in semen and increased sweating.

Some other side effects have been reported but there is not enough data to properly assess their frequency. These include: Migraines, swollen face and throat, skin rashes, disorders affecting blood flow to the eyes, irregular heartbeats, angina and cardiac death.

Taking Cialis and tadalafil with food and drink

Cialis and tadalafil can be taken with or without food, although it should be noted that all PDE-5 inhibitors tablets are slower to take effect when taken with food, particularly those containing large amounts of fat.

Alcohol may affect how these medications work and there is a risk that it will cause issues with low blood pressure when your blood alcohol levels exceed 0.08%.

You should avoid the consumption of grapefruit juice during treatment as it has also been known to affect the way the medication works.

How to minimise the risk of Cialis side effects

The most effective way to minimise the risk of side effects for Cialis and tadalafil is to follow the instructions given to you by your prescribing clinician. Some men will be instructed to take Cialis once a day. In these cases, it is important to take the medication at the same time and not more than once within a 24-hour period.

If you are not getting the desired effects from your treatment, you should not take a higher dosage without discussing it with your doctor first. The higher the dosage the more likely you will be to experience side effects and there is no guarantee that the medication will become more effective as a result.

Cialis side effects when taken with other medications

Your doctor will ask you about any other treatments you are currently taking before prescribing these medications. This should include any supplements, herbal treatments or over the counter medications. Some medications can interact negatively with Cialis and tadalafil, particularly nitrates, including those taken recreationally (such as amyl nitrates) and prescription medications, such as those prescribed for angina. Other medications might increase the risk of side effects that are already present with PDE-5 inhibitors, particularly those related to lowering blood pressure. You should also avoid the use of other erectile dysfunction medications alongside this treatment, whether they are similar treatments, such as Viagra (sildenafil), or other types, such as Caverject (alprostadil). 

Reporting Cialis side effects

If you experience any side effects with this medication, you can report them to the MHRA’s (Medicines and Healthcare Products Regulatory Agency) yellow card scheme, which tracks all known side effects relating to medications in the UK in order to provide the most accurate data possible.

Page last reviewed:  23/07/2020