Erectile Dysfunction

Inclusion Criteria

Subjects must fulfill all of the following criteria before being included in the treatment period i.e., before receiving any dose of the study related medication (Sponsor supplied Procardia XL, or vardenafil Orally Disintegrating Tablet (ODT) /placebo tablets):
 - The informed consent must be signed before any study specific tests or procedures are done
 - Male gender
 - Diagnosis of both essential hypertension (HTN) and erectile dysfunction (ED)
 - High blood pressure, or hypertension, is defined in an adult as a systolic pressure of 140 mm Hg or higher and/or a diastolic pressure of 90 mm Hg or higher.  As stated in the current American Heart Association guidelines.
 - Documented ED for more than 6 months according to the National Institutes of Health (NIH) Consensus statement (the inability to achieve or maintain penile erection sufficient for satisfactory sexual performance).  The diagnosis for ED will be confirmed using the five-item version (Rosen RC) of the International Index of Erectile Function (IIEF-5), see Appendix 14.4.  The total IIEF-5 score must be at least 8, and not exceed 19.  Subjects must have used at least one Phosphodiesterase-5 (PDE-5) inhibitor, such as Viagra, Levitra or Cialis at some time prior to entry in this study.  
 - Age: 65 to 80 years (inclusive) at the first screening examination / visit
 - Body mass index (BMI): above/equal 18 and below/equal 32 kg / m²

Exclusion Criteria

Subjects are to be excluded from the study if they display any of the following criteria:
Medical and surgical history
 - Pre-existing diseases for which it can be assumed that the absorption, distribution, metabolism, elimination and effects of the study drugs will not be normal.  This includes severe renal impairment (on dialysis or not) and moderate or severe hepatic disease.
 - Known hypersensitivity to calcium channel blockers (active substances or excipients of the tablet preparations)  
 - Known hypersensitivity to PDE-5 inhibitors, such as Viagra, Levitra or Cialis (active substances or in some instances, excipients of the tablet preparations should be considered as possible allergens, e.g., lactose, aspartame)  
 - Known severe allergies, non-allergic drug reactions, or multiple drug allergies
 - Recent history (within 6 months) of myocardial infarction (MI), coronary artery bypass graft (CABG), percutaneous transluminal coronary angioplasty (PTCA), stenting, or cerebrovascular accident (CVA)
 - Known left ventricular outflow syndrome (LVO)
 - History of significant coronary artery disease, e.g., angina
 - Congenital or acquired prolonged QT syndrome
 - Congestive heart failure (CHF) [NYHA Class 3 or 4]
 - History of adult epilepsy or other seizure disorders
 - History of retinitis pigmentosa
 - Use of any anti-hypertensive medication other than the calcium channel blocker, Procardia XL (nifedipine), supplied by the sponsor, during the study
 - Any drug known to induce cytochrome P450 (CYP) enzymes (eg rifampicin, carbamazepine, phenytoin, bosentan, dexamethasone, barbiturates, St. John’s Wort [hypericum perforatum])
 - Any drug known to inhibit CYP enzymes: specifically potent or moderate cytochrome P450 isoenzyme 3A4 (CYP3A4) inhibitors such as HIV protease inhibitors (e.g. ritonavir, indinavir, saquinavir, atazanavir), ketoconazole, itraconazole, clarithromycin and erythromycin
 - Use of nitroglycerin or any form of nitrates is not allowed
 - All alpha-blockers (e.g., Hytrin, Flomax, Uroxatral) are prohibited
Electrocardiogram (ECG), blood pressure, heart rate
 - Clinically relevant findings in the ECG such as a second- or third-degree AV block, prolongation of the QRS complex over 120 msec or of the QTc-interval over 450 msec 
 - Systolic blood pressure below 110 or above 150 mmHg on anti-hypertensive therapy
 - Diastolic blood pressure below 60 or above 95 mmHg on anti-hypertensive therapy 
 - Heart rate below 40 or above 95 beats / min on anti-hypertensive therapy
 - Serum creatinine > 2.5 mg/dL at Screening
 - HbA1c > 8% indicative of uncontrolled DM at Screening