User Description:
The erectile response, as assessed by RigiScan®, generally increased with increasing sildenafil dose and plasma concentration. In a double-blind study, 144 patients with erectile dysfunction and chronic stable angina limited by exercise, not receiving chronic oral nitrates, were randomized to a single dose of placebo or sildenafil citrate 100 mg 1 hour prior to exercise testing. Of the four subjects who received sildenafil citrate 100 mg in the first part of this study, a severe adverse event related to blood pressure effect was reported in one patient (postural hypotension that began 35 minutes after dosing with sildenafil citrate with symptoms lasting for 8 hours), and mild adverse events potentially related to blood pressure effects were reported in two others (dizziness, headache and fatigue at 1 hour after dosing; and dizziness, lightheadedness and nausea at 4 hours after dosing). Agents for the treatment of erectile dysfunction including sildenafil, should be used with caution in patients with anatomical deformation of the penis (such as angulation, cavernosal fibrosis or Peyronie's disease), or in patients who have conditions which may predispose them to priapism (such as sickle cell anaemia, multiple myeloma or leukaemia). Physicians should consider whether their patients with underlying NAION risk factors could be adversely affected by use of PDE5 inhibitors. Such an event may be a sign of non-arteritic anterior ischemic optic neuropathy (NAION), a rare condition and a cause of decreased vision including permanent loss of vision, that has been reported rarely post-marketing in temporal association with the use of all PDE5 inhibitors. 5.3 Effects on the Eye Physicians should advise patients to stop use of all phosphodiesterase type 5 (PDE5) inhibitors, including sildenafil citrate, and seek medical attention in the event of a sudden loss of vision in one or both eyes. There are no controlled clinical data on the safety or efficacy of sildenafil citrate in patients with retinitis pigmentosa (a minority of these patients have genetic disorders of retinal phosphodiesterases); if prescribed, this should be done with caution. Individuals who have already experienced NAION are at increased risk of NAION recurrence. Patients who have suffered a myocardial infarction, stroke, or life-threatening arrhythmia within the last 6 months; Patients with resting hypotension (BP 170/110 mmHg); Patients with cardiac failure or coronary artery disease causing unstable angina. If sildenafil citrate is prescribed to patients taking ritonavir, caution should be used. Effects of Sildenafil citrate on Blood Pressure: Single oral doses of sildenafil (100 mg) administered to healthy volunteers produced decreases in sitting blood pressure (mean maximum decrease in systolic/diastolic blood pressure of 8.3/5.3 mmHg). Effects of Sildenafil citrate on Cardiac Parameters: Single oral doses of sildenafil up to 100 mg produced no clinically relevant changes in the ECGs of normal male volunteers. Similar effects on blood pressure were noted with 25 mg, 50 mg and 100 mg of Sildenafil citrate, therefore the effects are not related to dose or plasma levels within this dosage range. buy cialis of visual function at doses up to twice the maximum recommended dose revealed no effects of sildenafil citrate on visual acuity, intraocular pressure, or pupillometry. However, Sildenafil tablets may be taken anywhere from 30 minutes to 4 hours before sexual activity (2.1) Based on effectiveness and toleration, may increase to a maximum of 100 mg or decrease to 25 mg (2.1) Maximum recommended dosing frequency is once per day (2.1) 2.1 Dosage Information For most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. When a single 100 mg dose of sildenafil citrate was administered with erythromycin, a moderate CYP3A4 inhibitor, at steady state (500 mg bid for 5 days), there was a 160% increase in sildenafil Cmax and a 182% increase in sildenafil AUC. 5.6 Adverse Reactions with the Concomitant Use of Ritonavir The concomitant administration of the protease inhibitor ritonavir substantially increases serum concentrations of sildenafil (11-fold increase in AUC). 5 Pharmacokinetics in Special Populations Geriatrics: Healthy elderly volunteers (65 years or over) had a reduced clearance of sildenafil, resulting in approximately 84% and 107% higher plasma AUC values of sildenafil and its active N-desmethyl metabolite, respectively, compared to those seen in healthy younger volunteers (18 to 45 years). Plasma concentrations of this metabolite are approximately 40% of those seen for sildenafil, so that the metabolite accounts for about 20% of sildenafil’s pharmacologic effects. What side effects may I notice from receiving Viagra? Dr Jackson mentioned this was a possible side effect, but I've cranked the heating up in my flat, so maybe I'm just imagining things. Since all of those factors can disrupt sleep, it was important to factor those out in order to label poor sleep as the possible cause, Faubion said.
