Cialis Side Effects

Cialis was administered to over 4000 subjects (aged 19 to 86 years) during clinical trials worldwide. Over 230 patients were treated for longer than one year and over 720 patients were treated for over 6 months. In controlled phase 2/3 clinical trials, the discontinuation rate due to Cialis side effects (1.7%) was not significantly different from placebo-treated patients (1.1%). In these studies, the side effects reported with Cialis were generally mild or moderate, transient, and decreased with continued dosing.

Like all prescription medications, Cialis may produce some side effects. These side effects are generally mild to moderate in nature and usually go away within a few hours of use.

The following Cialis side effects have been reported:

•  Headache

•  Back pain: In clinical trials, Back pain or myalgia was reported to occur 12 to 24 hours after dosing and typically resolved within 48 hours. This side effect was characterized by discomfort in the diffuse bilateral lumbar, gluteal, thigh, or thoracolumbar muscular discomfort. In general, the pain was reported as mild or moderate in severity and resolved without medical treatment, but severe back pain was reported infrequently (<5% of all reports).

•  Colour Vision: Changes in colour vision is rare. Across all studies, (<0.1%) of patients experienced it. .

•  Effects on the Digestive System : Effects include diarrhea, dry mouth, dysphagia, esophagitis , abnormal liver, loose stools, nausea, upper abdominal pain, vomiting and gastroesophageal reflux.

•  Nervous : Dizziness, hypesthesia, insomnia, paresthesia, somnolence and vertigo.

•  Cardiovascular: Angina pectoris, chest pain, hypotension, hypertension, myocardial infarction, and palpitations.

•  Musculoskeletal: Arthralgia, neck pain.

•  Respiratory: Dyspnea, epistaxis and pharyngitis.

•  Nasal congestion

•  Flushing

There may be additional unreported Cialis side effects.

Effect of other drugs on Cialis

Cytochrome P450 Inhibitors

CIALIS is predominantly metabolized by CYP3A4. Studies have shown that drugs that inhibit CYP3A4 can increase Tadalafil exposure

•  Ketoconazole – Ketoconazole , a selective inhibitor of CYP3A4, increases Tadalafil 20-mg single-dose exposure (AUC) by 312% and C max by 22%, relative to the values for Tadalafil 20 mg alone. Ketoconazole (200 mg) increases Tadalafil 10-mg single-dose exposure (AUC) by 107% and C max by 15%, relative to the values for Tadalafil 10 mg alone.

•  HIV Protease inhibitor – Ritonavir (200 mg twice daily), increases Tadalafil 20-mg single-dose exposure (AUC) by 124% with no change in C max , relative to the values for Tadalafil 20 mg alone. Other HIV protease inhibitors can also increase Tadalafil exposure.

•  Other cytochrome P450 inhibitors – Although specific interactions have not been studied, other CYP3A4 inhibitors, such as erythromycin, itraconazole, and grapefruit juice, would likely increase Tadalafil exposure.

Cytochrome P450 Inducers
Studies have shown that drugs that induce CYP3A4 can decrease tadalafil exposure.

•  Rifampin – Rifampin (600 mg daily), reduces Tadalafil 10-mg single-dose exposure (AUC) by 88% and C max by 46%, relative to the values for Tadalafil 10 mg alone.

•  Other CYP3A4 inducers, such as carbamazepine, phenytoin, and phenobarbitol, can decrease Tadalafil exposure.

Gastrointestinal Drugs

•  H 2 antagonists – An increase in gastric pH resulting from dosage of nizatidine has no significant effect on Tadalafil.

•  Antacids – Simultaneous administration of an antacid (magnesium hydroxide/aluminum hydroxide) and Tadalafil reduces the apparent rate of absorption of Tadalafil without altering exposure (AUC) to Tadalafil.

Effects of CIALIS on Other Drugs

•  Drugs Metabolized by Cytochrome P450

CIALIS does not inhibit or induce drugs metabolized by Cytochrome P450 (CYP) isoforms.

•  Alcohol : Both alcohol and CIALIS, a PDE5 inhibitor, act as mild vasodilators. When mild vasodilators are taken in combination, blood-pressure-lowering effects of each individual compound may be increased. Substantial consumption of alcohol (e.g., 5 units or greater) in combination with CIALIS can lead to increase in heart rate, decrease in standing blood pressure, dizziness, and headache.

•  Anti-Hypertensives : Clinical studies were conducted to assess the effect of Tadalafil on the blood-pressure-lowering effects of selected anti-hypertensive medications.

•  Alpha Blockers : When Tadalafil was administered to patients taking Doxazosin , there was significant augmentation of the blood-pressure-lowering effect of doxazosin.