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Contraindications/Precautions Contraindicated in: Hypersensitivity; Concurrent use of nitrates;
sildenafil (sil-den-a-fil)
Pulmonary veno-occlusive disease; OB, Pedi: Newborns, women, children; Pedi: Revatio-Chronic use not recommended for pulmonary hypertension due to lack of efficacy andqrisk of death.
Revatio, Neogra
Classification
Use Cautiously in: Serious underlying cardiovascular disease (including history
Therapeutic: erectile dysfunction agents, vasodilators Pharmacologic: phosphodiesterase type 5 inhibitors Pregnancy Category B Indications Neogra: Erectile dysfunction. Revatio: Pulmonary arterial hypertension (WHO Group I).
Action Neogra: Enhances effects of nitric oxide released during sexual stimulation. Nitric ox-ide activates guanylate cyclase, which produces increased levels of cyclic guanosine monophosphate (cGMP). cGMP produces smooth muscle relaxation of the corpus cavernosum, which promotes increased blood flow and subsequent erection. cGMP also leads to vasodilation of the pulmonary vasculature. Sildenafil inhibits the enzyme phosphodiesterase type 5 (PDE5), PDE5 inactivates cGMP. Revatio: Produces vaso-dilation of the pulmonary vascular bed. Therapeutic Effects: Neogra: Enhanced blood flow to the corpus cavernosum and erection sufficient to allow sexual inter-course. Requires sexual stimulation. Revatio: Improved exercise tolerance and delay worsening of disease.
Pharmacokinetics Absorption: Rapidly absorbed (41%) after oral administration; IV administration results in complete bioavailability. Distribution: Widely distributed to tissues; negligible amount in semen. Protein Binding: 96%.
Metabolism and Excretion: Mostly metabolized by the liver (by P450 3A4 en-zyme system); one metabolite is active and accounts for 20% or more of drug effect. Metabolites excreted mostly (80%) in feces; 13% excreted in urine. Half-life: 4 hr (for sildenafil and active metabolite). TIME/ACTION PROFILE (vasodilation, ability to produce erection)
ROUTE PO
ONSET within 1 hr Canadian drug name.
PEAK 30 – 120 min Genetic Implication.
DURATION up to 4 hr
of MI, stroke, or serious arrhythmia within 6 mo), cardiac failure, or coronary artery disease with unstable angina; History of HF, coronary artery disease, uncontrolled hy-pertension (BP 170/110 mm Hg) or hypotension (BP 90/50 mm Hg), dehydration, autonomic dysfunction, or severe left ventricular outflow obstruction; Pulmonary hypertension secondary to sickle cell anemia (mayqrisk of vaso-occlusive crises); Concurrent treatment with antihypertensives or glipizide; Renal impairment (CCr 30 mL/min, hepatic impairment; all result inqblood levels;pdose required with Neogra); Anatomic penile deformity (angulation, cavernosal fibrosis, Peyronie disease); Conditions associated with priapism (sickle cell anemia, multiple myeloma, leukemia); Bleeding disorders or active peptic ulceration; History of sudden severe vision loss or at risk for non-arteritic ischemic optic neuropathy (NAION); mayqrisk of recurrence; Retinitis pigmentosa; Alpha adrenergic blockers (patients should be on stable dose of alpha blockers before starting sildenafil); Geri:qblood levels and may require lower doses; consider age-related decrease in cardiac, hepatic, and renal function as well as concurrent drug therapy and chronic disease states; Lactation: Lactation.
Adverse Reactions/Side Effects CNS: headache, dizziness, insomnia. EENT: epistaxis, hearing loss, nasal congestion, vision loss. CV: MYOCARDIAL INFARCTION, SUDDEN DEATH, hypotension, vaso-oc-
clusive crises. GI: dyspepsia, diarrhea. GU: priapism, urinary tract infection. Derm: flushing, rash. MS: mylagia. Neuro: paresthesias.
Interactions Drug-Drug: Concurrent use of nitrates may cause serious, life threatening hypotension and is contraindicated. Blood levels and effects, including the risk of hypo-tension may beqby enzyme inhibitors including cimetidine, erythromycin, tacrolimus, ketoconazole, itraconazole, and protease inhibitor antiretro-virals including nelfinavir, indinavir, ritonavir, and saquinavir (initial dose of sildenafil for erectile dysfunction should bepto 25 mg) (concurrent use of potent CYP3A inhibitors not recommended with oral Revatio).qrisk of hypotension with al-
CAPITALS indicate life-threatening, underlines indicate most frequent. Strikethrough
Discontinued.
2 pha adrenergic blockers and acute ingestion of alcohol. Rifampin, bosentan, barbiturates, carbamazepine, phenytoin, efavirenz, nevirapine, rifampin or rifabutin maypblood levels and effects; dose adjustments may be necessary in the treatment of pulmonary arterial hypertension.qlevels of bosentan. Use cau-tiously with glipizide. Mayqrisk of bleeding with warfarin.
Route/Dosage Neogra (for erectile dysfunction) PO (Adults): 50 mg taken 1 hr before sexual activity (range 25 – 100 mg taken 30 min – 4 hr before sexual activity); not more than once daily; Concurrent use with al-pha-blocker antihypertensives— do not use 50 – 100 mg dose within 4 hr of alpha blocker, 25-mg dose may be taken anytime. PO (Geriatric Patients $65 yr or with concurrent enzyme inhibitors): 25 mg taken 1 hr before sexual activity (range 25 – 100 mg taken 30 min – 4 hr before sex-ual activity); not more than once daily.
Hepatic/Renal Impairment PO (Adults): 25 mg taken 1 hr before sexual activity (range 25 – 100 mg taken 30 min – 4 hr before sexual activity); not more than once daily.
Revatio (for pulmonary arterial hypertension) IV therapy is indicated for patients unable to take PO therapy
PO (Adults): 20 mg 3 times daily; dose adjustments may be necessary for concur-rent bosentan, barbiturates, carbamazepine, phenytoin, efavirenz, nevirapine, rifam-pin, or rifabutin. IV (Adults): 10 mg 3 times daily.
NURSING IMPLICATIONS Assessment ● Neogra: Determine erectile dysfunction before administration.
Sildenafil has no effect in the absence of sexual stimulation. ● Revatio: Monitor hemodynamic parameters and exercise tolerance prior to and periodically during therapy.
Potential Nursing Diagnoses
Sexual dysfunction (Indications) Risk for activity intolerance (Indications)
Implementation ● Do not confuse Neogra (sildenafil) with Allegra (fexofenadine). ● PO: Dose for erectile dysfunction is usually administered 1 hr before sexual activity. May be administered 30 min – 4 hr before sexual activity. ● Dose for pulmonary arterial hypertension is administered 3 times daily
without regard to food. Doses should be spaced 4 – 6 hr apart.
● Use syringe provided for accurate dosing of oral suspension.
IV Administration ● Direct IV: Administer undiluted. Solution is clear and colorless; do not admin-
ister solutions that are discolored or contain a precipitate. Rate: Administer as a bolus three times daily.
Patient/Family Teaching ● Instruct patient to take sildenafil as directed. For erectile dysfunction, take ap-
proximately 1 hr before sexual activity and not more than once per day. If taking sildenafil for pulmonary arterial hypertension, take missed doses as soon as re-membered unless almost time for next dose; do not double doses. ● Advise patient that Neogra is not indicated for use in women.
● Caution patient not to take sildenafil concurrently with alpha-adrenergic blockers
(unless on a stable dose) or nitrates. If chest pain occurs after taking sildenafil, instruct patient to seek immediate medical attention. Advise patient taking silden-afil for pulmonary arterial hypertension to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
● Instruct patient to notify health care professional promptly if erection lasts
longer than 4 hr or if experience sudden or decreased vision loss in one or both eyes or loss or decrease in hearing, ringing in the ears, or dizziness. ● Inform patient that sildenafil offers no protection against sexually
transmitted dis-eases. Counsel patient that protection against sexually transmitted diseases and HIV infection should be considered.
Evaluation/Desired Outcomes ● Male erection sufficient to allow intercourse. ● Increased exercise tolerance.
Why was this drug prescribed for your patient? 2015 F.A. Taj Pharma India Company