Erectile Dysfunction ( Viagra only)
Adults: PO 50 mg once, 0.5 to 4 h prior to sexual activity. Titration to a 25 or a 100 mg dose may be used based on tolerability or efficacy. The max recommended dosage is 100 mg per day and max recommended frequency is once daily.
Dosage Adjustments ( Viagra only)
Adults: PO Consider a starting dose of 25 mg in patients older than 65 yr of age, or in patients with hepatic impairment, severe renal impairment, or concurrent use of potent CYP3A4 inhibitors (eg, erythromycin, itraconazole, ketoconazole, saquinavir).
Alpha-blockers: Patients should be on stable alpha-blocker therapy prior to initiating treatment and should be initiated on sildenafil at the lowest dose.
Protease inhibitors: Do not exceed a max single dose of sildenafil 25 mg in a 48-h period.
Pulmonary Arterial Hypertension ( Revatio only)
Adults: PO 20 mg 3 times daily. IV 10 mg (12.5 mL) administered as a bolus injection 3 times daily.
|•||Administer without regard to meals. Administer with food if GI upset occurs.|
Viagra: Enhances the effect of nitric oxide by inhibiting phosphodiesterase type 5 (PDE5) in the corpus cavernosum of the penis. This results in vasodilation and increased inflow of blood into the corpus cavernosum, with ensuing penile erection upon sexual stimulation.
Revatio: Inhibits cGMP-specific PDE5 in the smooth muscle of the pulmonary vasculature, where PDE5 is responsible for degradation of cGMP. This increases cGMP within pulmonary vascular smooth muscle cells, resulting in relaxation. This leads to vasodilation of the pulmonary vascular bed in patients with pulmonary hypertension.
Use with nitrates; hypersensitivity to any component of the product.
CV: Abnormal ECG, angina pectoris, AV block, cardiac arrest, cardiomyopathy, cerebral thrombosis, heart failure, hypotension, myocardial ischemia, palpitation, postural hypotension, syncope, tachycardia (less than 2%); cerebrovascular hemorrhage, hypertension, MI, pulmonary hemorrhage, subarachnoid and intracerebral hemorrhages, sudden cardiac death, transient ischemic attack, ventricular arrhythmia (postmarketing).
CNS: Headache (46%); insomnia (7%); paresthesia (3%); dizziness (2%); abnormal dreams, ataxia, decreased reflexes, depression, hypertonia, hypesthesia, insomnia, migraine, neuralgia, neuropathy, somnolence, tremor, vertigo (less than 2%); anxiety, seizure, seizure recurrence, transient global amnesia (postmarketing).
DERM: Flushing (10%); erythema (6%); rash (2%); contact dermatitis, exfoliative dermatitis, herpes simplex, pruritus, skin ulcer, sweating, urticaria (less than 2%).
EENT: Epistaxis (9%); nasal congestion, rhinitis (4%); abnormal vision (mild and transient, predominantly color tinge to vision, increased sensitivity to light, or blurred vision) (3%); cataract, conjunctivitis, dry eyes, ear pain, eye hemorrhage, eye pain, mydriasis, photophobia, sudden decrease or loss of hearing, tinnitus (less than 2%); bloodshot appearance, diplopia, increased IOP, ocular burning, ocular redness, ocular swelling/pressure, paramacular edema, retinal vascular disease or bleeding, temporary vision loss/decreased vision, vitreous detachment/traction (postmarketing).
GI: Dyspepsia (13%); diarrhea (9%); gastritis (3%); colitis, dry mouth, dysphagia, esophagitis, gastroenteritis, gingivitis, glossitis, rectal hemorrhage, stomatitis, vomiting (less than 2%).
GU: UTI (3%); abnormal ejaculation, anorgasmia, breast enlargement, cystitis, genital edema, nocturia, urinary frequency, urinary incontinence (less than 2%); hematuria, priapism, prolonged erection (postmarketing).
HEMA: Anemia, leukopenia (less than 2%).
HEPA: Abnormal LFTs (less than 2%).
METAB: Edema, gout, hyperglycemia, hypernatremia, hyperuricemia, hypoglycemic reaction, peripheral edema, thirst, unstable diabetes.
MUSC: Myalgia (7%); arthritis, arthrosis, bone pain, myasthenia, synovitis, tendon rupture, tenosynovitis.
RESP: Dyspnea exacerbated (7%); sinusitis (3%); asthma, bronchitis, dyspnea, increased cough, increased sputum, laryngitis, pharyngitis (less than 2%).
OTHER: Pyrexia (6%); abdominal pain, accidental falls, accidental injury, allergic reaction, asthenia, chest pain, chills, face edema, pain, photosensitivity, shock (less than 2%).
Alpha-blockers (eg, doxazosin)
Simultaneous administration may lead to symptomatic hypotension. When sildenafil is coadministered with an alpha-blocker, patients should be on stable alpha-blocker therapy prior to initiating treatment; initiate sildenafil at the lowest dose. In patients already taking an optimized dose of sildenafil, initiate alpha-blocker therapy at the lowest dose.
Coadministration produced an additional mean reduction in BP of 8/7 mm Hg. Monitor BP and adjust the amlodipine dose as needed.
BP-lowering effects of antihypertensive agents may be increased. Monitor BP and adjust the dose of the antihypertensive agent as needed.
Coadministration may result in a decrease in sildenafil AUC and Cmax . In addition, sildenafil administration may increase bosentan AUC and Cmax . Use with caution. Monitor the clinical response of the patient and observe for bosentan adverse reactions.
CYP3A4 inhibitors (eg, azole antifungal agents [eg, itraconazole, ketoconazole], cimetidine, fluvoxamine, macrolide antibiotics [eg, erythromycin], protease inhibitors [eg, ritonavir, saquinavir], tacrolimus)
Sildenafil plasma levels may be elevated, increasing the risk of adverse reactions. Use with caution. Consider starting with a lower dose of sildenafil. In patients receiving azole antifungal agents or saquinavir, consider a starting dose of sildenafil 25 mg. In patients taking ritonavir, the dose of sildenafil should not exceed 25 mg in a 48-h period.
Use with caution. Coadministration may substantially increase sildenafil plasma levels. Consider a max dose of sildenafil 25 mg in a 48-h period in patients taking delavirdine.
When sildenafil is taken with a high-fat meal, the rate of absorption is reduced, with a mean delay in Tmax of 60 min and a mean reduction in Cmax of 29%. If taken after a high-fat meal (eg, cheeseburger and french fries), sildenafil may take slightly longer for the onset of effect.
Sildenafil plasma concentrations may be prolonged; however, data are conflicting. Observe the patient for sildenafil adverse reactions and adjust treatment as needed.
HMG-CoA reductase inhibitors (eg, simvastatin)
At least 1 case of rhabdomyolysis has been reported during coadministration of sildenafil and simvastatin. Advise patients to report any unexplained muscle pain, tenderness, or weakness to their health care provider.
Inducers of CYP3A4 (eg, rifampin)
May decrease sildenafil levels. Closely monitor the clinical response to sildenafil.
Sildenafil has been shown to potentiate the hypotensive effects of nitrates. Coadministration is contraindicated.
Opioid analgesics (eg, dihydrocodeine)
Effects of sildenafil may be prolonged, resulting in prolonged erections following orgasm.
Vitamin K antagonists
Coadministration may lead to increased bleeding (primarily epistaxis). Closely monitor the patient for bleeding. If indicated, consider administering vitamin K.
Therapeutic Classification: Erectile dysfunction, Pulmonary Hypertention
Pharmacologic Classification: phosphodiesterase type 5 inhibitors
Absorption: Bioavailability is 41%. Tmax is 30 to 120 min (mean, 60 min). The drug is rapidly absorbed. When taken with a high-fat meal, the absorption rate is reduced with a mean delay in Tmax of 60 min and a mean reduction of Cmax of 29%.
Distribution: Vd is 105 L; 96% bound to plasma proteins.
Metabolism: Undergoes hepatic metabolism (mainly CYP3A4). The major circulating metabolite results from N-desmethylation.
Excretion: Half-life is 4 h. The drug is cleared primarily by the CYP3A4 (major route) and CYP2C9 (minor route) hepatic microsomal isoenzymes, and is excreted primarily in feces (approximately 80%) and, to a lesser extent, in urine (approximately 13%).
|ORAL||WITHIN 1 HOUR||30-120 MINUTE||UPTO 4 HOUR|