Drug Name
Generic Name : sildenafil citrate
Brand Name: Revatio, Viagra
Classification: Impotence drug, Phosphodiesterase inhibitor
Pregnancy Category B
Dosage & Route
ADULTS
- Erectile dysfunction: 50 mg PO taken 1 hr before anticipated sexual activity; range 25–100 mg PO. May be taken 30 min–4 hr before sexual activity. Limit use to once per day.
- Pulmonary arterial hypertension: 20 mg PO tid, at least 4–6 hr apart and without regard to food.
PEDIATRIC PATIENTS
- Not intended for use in children.
GERIATRIC PATIENTS
- For patients > 65 yr, start dose at 25 mg PO when used for erectile dysfunction.
PATIENTS WITH RENAL OR HEPATIC IMPAIRMENT
- Patients with hepatic impairment or creatinine clearance < 30 mL/min may have increased serum levels; start dose at 25 mg PO.
Therapeutic actions
- Sildenafil inhibits phosphodiesterase type-5 (PDE5) which is responsible for cGMP degradation in the corpus cavernosum. Inhibition of PDE5 increases cGMP levels in the corpus cavernosum which results in smooth muscle relaxation and inflow of blood to the corpus cavernosum.
Indications
- Treatment of erectile dysfunction in the presence of sexual stimulation. See Blink Health for viagra online
- Treatment of pulmonary arterial hypertension to improve exercise ability
Adverse effects
- Headache, flushing, respiratory tract infection, angina pectoris, AV block, migraine, syncope, tachycardia, postural hypotension, MI, cerebral thrombosis, cardiac arrest, paresthesia, tremor, depression, herpes simplex, skin ulcer, esophagitis, abnormal LFT, rectal hemorrhage, hypoglycemic reaction, arthritis, deafness, retinal vascular disease, photosensitivity, accidental fall.
Contraindications
- Hypersensitivity. Patients concurrently or intermittently using organic nitrates in any form.
Nursing considerations
Assessment
- History: Allergy to any component of the tablet; hepatic or renal impairment; with anatomical deformation of the penis, known cardiac disease; concomitant use of nitrates
- Physical: Orientation, affect; skin color, lesions; P, BP, ECG, LFTs, renal function tests
Interventions
- Ensure diagnosis of pulmonary arterial hypertension (Revatio)
- Ensure diagnosis of erectile dysfunction and determine underlying causes and other appropriate treatment.
- Advise patient that drug does not work in the absence of sexual stimulation. Limit use to once per day.
- Remind patient that drug does not protect against sexually transmitted diseases and appropriate measures should be taken.
- WARNING: Advise patient to never take this drug with nitrates; serious and even fatal complications can occur.
- WARNING: Advise patients receiving HIV medications that there is an increased risk of sidenafil-associated adverse drug reactions, including hypotension, visual changes, and priapism. Do not exceed 25 mg of sildenafil in 48 hr.
- WARNING: Advise patients not to take this drug within 4 hr of alpha blocker.
Teaching points
- Take this drug 30 minutes to 4 hours before anticipated sexual activity. The usual timing is 1 hour. The drug will have no effect in the absence of sexual stimulation.
- If taking this drug for pulmonary arterial hypertension, take three times a day; make sure the doses are 4-6 hours apart.
- Onset of drug effects will be slowed if taken with a high-fat meal; plan accordingly. Avoid drinking grapefruit juice if using this drug.
- This drug will not protect you from sexually transmitted diseases; use appropriate precautions.
- Stop the drug and call your health care provider immediately if you experience sudden loss of vision.
- Do not take this drug if you are taking any nitrates; serious side effects and even death can occur.
- You may experience these side effects: Headache, dizziness, rash, flushing.
- Report difficult or painful urination, rash, dizziness, palpitations, loss of vision.