tadalafil

ta·da·la·fil (t-dl-fl)

n.

A phosphodiesterase inhibitor drug used to treat erectile dysfunction for up to several days by increasing the level of cyclic GMP, which increases blood flow to the erectile tissues.

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tadalafil,

an impotence agent.

indication This drug is used in the treatment of erectile dysfunction.

contraindications Known hypersensitivity to this drug prohibits its use. Patients who are taking organic nitrates either regularly or intermittently and patients taking any alpha-adrenergic antagonist other than tamsulosin (0.4 mg once daily) should not take this drug.

adverse effects Adverse effects of this drug include back pain or myalgia, blurred vision, changes in color vision, and pruritus. Life-threatening side effects include myocardial infarction, cardiovascular collapse, and sudden death. Common side effects include headache, flushing, dizziness, dyspepsia, nasal congestion, urinary tract infection, and diarrhea.

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tadalafil

Cialis

Pharmacologic class: Phosphodiesterase type 5 (PDE5) inhibitor

Therapeutic class: Anti-erectile dysfunction agent

Pregnancy risk category B

Action

Inhibits PDE5, increasing cyclic guanosine monophosphate level and enhancing erectile function

Availability

Tablets: 5 mg, 10 mg, 20 mg

⊘Indications and dosages

➣ Erectile dysfunction

Adults: Initially, 10 mg P.O. before anticipated sexual activity; may increase to 20 mg or decrease to 5 mg based on patient response and tolerance. For most patients, maximum recommended dosing frequency is once daily.

Dosage adjustment

• Mild to moderate hepatic impairment or renal insufficiency

Contraindications

• Hypersensitivity to drug or its components
• Concurrent use of organic nitrates (regularly or intermittently)
• Concurrent use of alpha-adrenergic agonists (except tamsulosin 0.4 mg/day)

Precautions

Use cautiously in:
• cardiac risk that makes sexual activity inadvisable, renal insufficiency, hepatic impairment, left ventricular outflow obstruction, erectile dysfunction whose cause hasn't been evaluated, conditions that increase risk of priapism
• concurrent use of potent CYP450-3A4 inhibitors.

Administration

• Know that patient should take drug (with or without food) before anticipated sexual activity.

Route	Onset	Peak	Duration
P.O.	Rapid	30 min-6 hr	Up to 36 hr

Adverse reactions

CNS: headache, fatigue, dizziness, insomnia, hyperesthesia, paresthesia, drowsiness, vertigo, asthenia

CV: angina pectoris, chest pain, hypertension, hypotension, orthostatic hypotension, palpitations, syncope, tachycardia, myocardial infarction

EENT: blurred vision, color vision changes, conjunctivitis, eye pain, increased lacrimation, eyelid swelling, epistaxis, nasal congestion, pharyngitis

GI: nausea, vomiting, diarrhea, dyspepsia, esophagitis, gastroesophageal reflux, gastritis, upper abdominal pain, dysphagia, dry mouth

GU: increased or spontaneous erection

Musculoskeletal: myalgia; back, neck, limb, and joint pain

Respiratory: dyspnea

Skin: pruritus, rash, sweating

Other: facial edema, pain

Interactions

Drug-drug. Alpha-adrenergic blockers (except tamsulosin 0.4 mg/day): marked blood pressure decrease

Angiotensin receptor blockers, enalapril, metoprolol: decreased blood pressure

CYP450-3A4 inducers (such as carbamazepine, phenobarbital, phenytoin, rifampin): decreased tadalafil blood level

CYP450-3A4 inhibitors (such as erythromycin, itraconazole, ketoconazole, ritonavir): increased tadalafil blood level

Theophylline: slight increase in heart rate

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, lactate dehydrogenase, uric acid: increased levels

Drug-food. Grapefruit juice: increased drug blood level

Patient monitoring

• Monitor for drug efficacy.

Patient teaching

• Advise patient to take before anticipated sexual activity.
☞ Caution patient never to take concurrently with nitrates.
☞ Instruct patient to stop sexual activity and contact prescriber immediately if chest pain, dizziness, or nausea occurs.
• Instruct patient to contact prescriber if erection lasts more than 4 hours.
• Tell patient drug can cause serious interactions with many common drugs. Instruct him to tell all prescribers he's taking it.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• Inform patient that drug may cause temporary blood pressure drop, leading to light-headedness if he stands up suddenly. Advise him to rise slowly and carefully.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and foods mentioned above.