Cialis (tadalafil) is yet another medication that is both sinner and saint. We have already presented many of Cialis' excellent properties and you can read my link on The Long Term Benefits of Cialis for more details. However, Cialis also has a darker side as well, one that your doctor is unlikely to tell you about. It is important to examine the potentially ugly side of any drug, but especially Cialis since most guys are so glad to get rid of their erectile dysfunction that they think, "Side effects, schmide effects - I'm in the saddle again!"
NOTE: Cialis has recently come out with a Cialis Daily lower dose version that can keep a guy in the game 24/7. Eli Lilly's info page is here.
Below are some of the concerns that researchers and medical professionals have noted with Cialis on a daily basis:
1) Brain. Headaches are extemely common with Cialis (tadalafil). In one 4 week study, 7.2 percent of patients experienced headaches.  This is almost one out of every 14 patients and shows that Cialis is affecting something in the brain. Viagra, a fellow PDE5 Inhibitor like Cialis, has actually been studied more extensively and found to effect the brain on the neurotransmitter level. For example, researchers have found that it 1) causes anxiety in rodents and 2) exhibits some antidepressant like qualities.  The bottom line is that Cialis and the other PDE5 inhibitors are clearly affecting the brain in a profound way and researchers have almost no understanding as to how. So I will ask the question, "Is something that causes headaches in one out of 14 men really going to be good for your long term health after decades of use?"
2) Backache and Muscle Pain. These are quite common with Cialis and often do not go away for 24-48 hours.  Again, what is disconcerting is that researchers have no explanation. Just what is Cialis affecting?
3) Retina. Cialis also effects PDE6 to a significant extent. PDE6 is another related phosphodiesterase enzyme and is present in the retina. Here are the kind of all-too-common side effects reported with regular tadalafil (Cialis) use: "Transient changes in vision, transient and mild impairment in color discrimination, eye pain, eyelid swelling, electroretinographic abnormalities, abnormal histopathologic findings,4 pupil-sparing third nerve palsy, and central serous choroidopathy have been reported."  Again, after decades of use, what is this going to do to your vision?
4) Cortisol. Cortisol is one of the biggest enemies of the middle-aged and beyond male. If too high for too long of a time, it decreases testosterone, increases visceral fat, increases insulin resistance and destroys neurons just for starters.  Now Cialis has also been found to improve the testosterone to estrogen ratio, but the truth is that we just do not know if the increase in cortisol could cause long term issues. Could it slightly increase the chances for visceral fat? metabolic syndrome? We just don't know.
1) European Urology, Sep 2004, 46(3):362-369, "Efficacy and Treatment Satisfaction with On-Demand Tadalafil (Cialis ) in Men with Erectile Dysfunction"
2) J Neural Transm, 2007 Sep 7, "Appearance of antidepressant-like effect by sildenafil in rats after central muscarinic receptor blockade: evidence from behavioural and neuro-receptor studies"
4) Archives of Ophthalmology, Jul 2006, 124(7), "Tadalafil-Induced Subretinal and Choroidal Hemorrhage in a Patient With an Unsuspected Uveal (Choroidal and Ciliary Body) Melanoma"
5) J Clin Endocrinol Metab, 2008 Sep, 93(9):3510-4, Epub 2008 Jun 17, "The type 5 phosphodiesterase inhibitor tadalafil influences salivary cortisol, testosterone, and dehydroepiandrosterone sulphate responses to maximal exercise in healthy men"