Finasteride/tadalafil Disease Interactions

The use of phosphodiesterase-5 (PDE5) inhibitors is not recommended in patients with preexisting cardiovascular disease for whom sexual activity is inadvisable due to the potential cardiac risk. Physicians should also consider the vasodilatory effect of these drugs and whether they may adversely affect patients with underlying cardio- and/or cerebrovascular conditions, in particular those who have suffered a myocardial infarction, stroke, or life-threatening arrhythmia within the last 6 months; those with resting hypotension (BP < 90/50) or hypertension (BP > 170/110); and those with unstable angina associated with cardiac failure or coronary artery disease. There are no controlled clinical data on the safety or efficacy in such patients. Other adverse cardiovascular effects reported include angina pectoris, myocardial infarction, AV block, ventricular arrhythmia, tachycardia, palpitation, hypotension, postural hypotension, syncope, cerebral thrombosis, cerebrovascular hemorrhage, transient ischemic attack, cardiac arrest, heart failure, and hypertension. Many of these events occurred in patients with cardiovascular risk factors and during or shortly after sexual activity.

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The plasma clearance of phosphodiesterase-5 (PDE5) inhibitors may be decreased in patients with severe renal impairment, resulting in drug accumulation. Therapy with these agents should be avoided in patients with severe renal disease or on renal dialysis. Dose adjustments might be needed based on individual renal assessment and tolerability if used in these patients.

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Tadalafil tablet for the treatment of pulmonary arterial hypertension (PAH) should not be used in patients with pulmonary veno-occlusive disease (PVOD) as it may significantly worsen the cardiovascular status of these patients. If signs of pulmonary edema develop during therapy, the possibility of associated PVOD should be considered.

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Finasteride and dutasteride are extensively metabolized by the liver. Therapy with these drugs should be administered cautiously in patients with liver disease as exposure could be higher.

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Patients with large residual urinary volume and/or severely diminished urinary flow should be carefully monitored for obstructive uropathy. These patients may not be candidates for finasteride therapy.

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Prolonged erection greater than 4 hours and priapism (painful erections greater than 6 hours) have been reported during treatment with phosphodiesterase-5 (PDE 5) inhibitors. Priapism may result in penile tissue damage and permanent loss of potency if not treated promptly. These agents should be used cautiously in patients with conditions that may predispose them to priapism such as sickle cell anemia, multiple myeloma, or leukemia, and those with anatomical deformation of the penis (such as angulation, cavernosal fibrosis, or Peyronie's disease). If an erection persists longer than 4 hours, the patient should seek immediate medical assistance.

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Alcohol consumption may intensify the pressure-lowering effects of mild vasodilators, such as phosphodiesterase 5 (PDE5) inhibitors. Therefore, patients that consume alcohol should be warned to limit alcohol intake while receiving these agents.

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Use of phosphodiesterase-5 (PDE5) inhibitors has been associated with sudden decrease or loss of hearing, which may be accompanied by tinnitus or dizziness. Patients with hearing problems should stop taking these agents and seek prompt medical care.

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Phosphodiesterase 5 (PDE-5) inhibitors are cleared predominantly by hepatic metabolism. The pharmacokinetic disposition of these agents has not been assessed in patients with severe hepatic impairment. No dosage modification is recommended for patients with mild to moderate hepatic impairment, however, therapy with these agents should not be administered to patients with severe hepatic impairment. In patients with mild hepatic impairment a lower dose of these agents should be used as initial therapy.

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Phosphodiesterase-5 (PDE5) inhibitors have been associated with transient impairment of color discrimination (blue/green) and blue- or color-tinged vision. These agents also inhibit phosphodiesterase-6 (PDE6), to a much lesser extent, which is involved in phototransduction in the retina. There are no controlled clinical data on the safety in patients with retinitis pigmentosa, a minority of whom may have genetic disorders of retinal phosphodiesterases. Therapy with these agents should be avoided in such patients.

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The use of phosphodiesterase 5 (PDE-5) inhibitors has been associated with seizures. Therapy with these agents should be administered cautiously in patients with preexisting seizure disorders.

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Tadalafil for the treatment of erectile dysfunction (ED) should be used with caution and only if the benefit outweighs the risk in patients with a history of non-arteritic anterior ischemic optic neuropathy (NAION) or with retinitis pigmentosa. Use of tadalafil for the treatment of pulmonary arterial hypertension is not recommended in patients with retinitis pigmentosa. Advise patients to seek immediate medical attention in the event of a sudden loss of vision in one or both eyes while taking tadalafil; patients taking tadalafil for ED should immediately stop treatment. Most patients who developed NAION during therapy with tadalafil had underlying anatomic or vascular risk factors, including low cup to disc ratio ("crowded disc").

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