In dose period 1, subjects were administered open-label doxazosin and a single dose of VIAGRA 50 mg simultaneously, after at least 14 consecutive days of doxazosin. If a subject did not successfully complete this first dosing period, he was discontinued from the study. Subjects who had successfully completed the previous doxazosin interaction study (using VIAGRA 50 mg), including no significant hemodynamic adverse events, were allowed to skip dose period 1. Treatment with doxazosin continued for at least 7 days after dose period 1. Thereafter, VIAGRA 100 mg or matching placebo was administered simultaneously with doxazosin 4 mg (14 subjects) or doxazosin 8 mg (6 subjects) in standard crossover fashion. If you are taking sildenafil to treat erectile dysfunction, follow your doctor’s directions and the guidelines in this paragraph.
In the event of a medical emergency, you should tell your doctor, pharmacist or nurse that you have taken VIAGRA and when you did. Do not take VIAGRA with other medicines unless your doctor tells you that you can. In a study of healthy male volunteers, BUY XANAX WITHOUT PRESCRITION sildenafil (100 mg) did not affect the steady state pharmacokinetics of the HIV protease inhibitors, saquinavir and ritonavir, both of which are CYP3A4 substrates. The AUC of the active metabolite, N-desmethyl sildenafil, was increased 62% by loop and potassiumsparing diuretics and 102% by nonspecific beta-blockers. These effects on the metabolite are not expected to be of clinical consequence.
DOSAGE FORMS AND STRENGTHS
The safety and effectiveness of Viagra tablets that are crushed, split, or chewed haven’t been tested. It’s not known if crushing or chewing the tablets will make them work any differently than usual. You should take Viagra according to your doctor or healthcare professional’s instructions. There aren’t any foods that have been specifically reported to interact with Viagra.
What should I tell my healthcare provider before taking sildenafil?
If your symptoms are severe, call 911 or go to the nearest emergency room right away. This drug shouldn’t be used in children younger than 18 years of age. Talk with your doctor if you’re pregnant or planning to become pregnant. However, this drug should only be used during pregnancy if clearly needed. It is important to note that certain foods, particularly foods high in fat, can cause the drug to work more slowly than normal. It also comes in an intravenous (IV) form, which is only given by a doctor.
Therefore, PDE5 inhibitors, including VIAGRA, shouldbe used with caution in these patients and only when the anticipated benefitsoutweigh the risks. In fixed-dose studies, the incidence of some adverse reactions increased with dose. The type of adverse reactions in flexible-dose studies, which reflect the recommended dosage regimen, was similar to that for fixed-dose studies. At doses above the recommended dose range, adverse reactions were similar to those detailed in Table 1 below but generally were reported more frequently. Consider a starting dose of 25 mg in patients treated with strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, or saquinavir) or erythromycin. Clinical data have shown that co-administration with saquinavir or erythromycin increased plasma levels of sildenafil by about 3 fold [see DRUG INTERACTIONS and CLINICAL PHARMACOLOGY].