Cialis, or branded tadalafil, is a popular prescription drug used by many men in order to combat erectile dysfunction. 

That being said, there are factors such as health status, medication use and potential secondary effects that can render Cialis as an unsuitable option for some. 

It’s important to read the leaflet beforehand on how to take Cialis, as well as check to see if there are any medicines or medical conditions that apply to you, and may preclude use. 

Your prescriber should be made aware of these during consultation, but reading the leaflet through before use brings another layer of safety.

Why you need a prescription for Cialis

Firstly, it is important to remember that you should only buy and use Cialis with a prescription from a registered doctor. This is because there are certain criteria which need to be met to ensure the safe use of the drug. 

Cialis works well for a lot of men. In clinical trials, 81 percent of men using Cialis reported improved erections. But because the performance and results of ED drugs can differ, your prescriber will discuss the available options with you to determine which is most suitable (before issuing you with a prescription).

Health conditions and Cialis

The active ingredient in Cialis is a drug called Tadalafil. Because this can activate certain mechanisms in the body, there are particular health conditions that mean you should not take Cialis.

  • You should not use Cialis if you know that you have an allergy to tadalafil or any of the other listed ingredients. 
  • If you have serious heart disease or have experienced a recent heart attack (within the last 90 days) you should not use this medication. 
  • Men who have had a stroke in the past six months and those who have hypotension (low blood pressure) or uncontrolled hypertension (high blood pressure) are not suitable candidates for Cialis use. This is because Cialis use can put extra strain on the heart which can be dangerous, especially during sexual activity. 
  • Another Cialis contraindication is the condition called non-arteritic anterior ischemic optic neuropathy (NAION) which can cause a loss of vision and is sometimes referred to as a stroke of the eye. Any past vision issues should be disclosed to your doctor. 

Your doctor also needs to be made aware if you have, or have ever had: 

  • sickle cell anaemia 
  • multiple myeloma 
  • leukaemia 
  • a penis deformity 
  • or liver or kidney problems. 

Your prescriber will assess the suitability of Cialis against your current condition and medical history. 

Cialis and conflicting medications

  • Patients taking nitrates should avoid Cialis use. This group of medication is used to treat angina pectoris or chest pain. It has been noted that Cialis can increase the effects of these drugs. 
  • Riociguat is a drug used to treat some heart conditions. It is known to have a potentially dangerous interaction with Cialis and so the two medications are not prescribed at the same time. The interaction could decrease your blood pressure which may cause you to faint or even lead to a heart attack. 

The use of other medicines can also have an impact on the suitability of Cialis. Your doctor needs to know if you are taking any of the following: 

  • high blood pressure medication, such as alpha-blockers; 
  • 5-alpha reductase inhibitors; 
  • ketoconazole tablets; 
  • protease inhibitors; 
  • phenobarbital; 
  • phenytoin; 
  • carbamazepine; 
  • rifampicin; 
  • erythromycin; 
  • clarithromycin 
  • or itraconazole. 

It is also important to mention if you are using or have used other erectile dysfunction treatments. 

Side effects of Cialis

All medicines have the potential to cause side effects, although not all users go on to experience them. 

However, if you take Cialis and go on to experience:

  • an allergic reaction, 
  • chest pain, 
  • a prolonged and painful erection 
  • or temporary vision loss 

You should not continue your course and instead seek immediate medical attention. Although mostly uncommon these particular secondary effects can indicate that Cialis is an unsuitable option. 

The effects of Cialis on fertility have not been explored extensively, but in two studies carried out on over 400 men, no adverse effect was observed on spermatogenesis (a selection of measures including sperm count and concentration) when compared with placebo.

If you’re unsure about anything to do with this treatment, you can find more information on our Cialis (Tadalafil) FAQ page, or speak to your doctor or pharmacist.

Page last reviewed:  24/07/2020