Sildenafil

7 DRUG INTERACTIONS Sildenafil citrate can potentiate the hypotensive effects of nitrates, alpha blockers, and anti-hypertensives ( 4.1 , 5.5 , 7.1 , 7.2 , 7.3 , 12.2 ) With concomitant use of alpha blockers, initiate sildenafil citrate at 25 mg dose ( 2.3 ) CYP3A4 inhibitors (e.g., ritonavir, ketoconazole, itraconazole, erythromycin): Increase sildenafil citrate exposure ( 2.4 , 7.4 , 12.3 ) Ritonavir: Do not exceed a maximum single dose of 25 mg in a 48 hour period ( 2.4 , 5.6 ) Erythromycin or strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, saquinavir): Consider a starting dose of 25 mg ( 2.4 , 7.4 ) 7.1 Nitrates Administration of sildenafil tablets with nitric oxide donors such as organic nitrates or organic nitrites in any form is contraindicated. Co-administration of erythromycin, a moderate CYP3A4 inhibitor, resulted in a 160% and 182% increases in sildenafil C max and AUC, respectively. A starting dose of 25 mg of sildenafil tablets should be considered in patients taking erythromycin or strong CYP3A4 inhibitors (such as saquinavir, ketoconazole, itraconazole) [ see Dosage and Administration ( 2.4 ), Clinical Pharmacology ( 12.3 ) ] .

PDE5 inhibitor potentiates hypotensive effects of isosorbide dinitrate. Contraindicated.

7 DRUG INTERACTIONS Sildenafil citrate can potentiate the hypotensive effects of nitrates, alpha blockers, and anti-hypertensives ( 4.1 , 5.5 , 7.1 , 7.2 , 7.3 , 12.2 ) With concomitant use of alpha blockers, initiate sildenafil citrate at 25 mg dose ( 2.3 ) CYP3A4 inhibitors (e.g., ritonavir, ketoconazole, itraconazole, erythromycin): Increase sildenafil citrate exposure ( 2.4 , 7.4 , 12.3 ) Ritonavir: Do not exceed a maximum single dose of 25 mg in a 48 hour period ( 2.4 , 5.6 ) Erythromycin or strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, saquinavir): Consider a starting dose of 25 mg ( 2.4 , 7.4 ) 7.1 Nitrates Administration of sildenafil tablets with nitric oxide donors such as organic nitrates or organic nitrites in any form is contraindicated. Stronger CYP3A4 inhibitors such as ketoconazole or itraconazole could be expected to have greater effects than seen with saquinavir. A starting dose of 25 mg of sildenafil tablets should be considered in patients taking erythromycin or strong CYP3A4 inhibitors (such as saquinavir, ketoconazole, itraconazole) [ see Dosage and Administration ( 2.4 ), Clinical Pharmacology ( 12.3 ) ] .

7 DRUG INTERACTIONS Sildenafil citrate can potentiate the hypotensive effects of nitrates, alpha blockers, and anti-hypertensives ( 4.1 , 5.5 , 7.1 , 7.2 , 7.3 , 12.2 ) With concomitant use of alpha blockers, initiate sildenafil citrate at 25 mg dose ( 2.3 ) CYP3A4 inhibitors (e.g., ritonavir, ketoconazole, itraconazole, erythromycin): Increase sildenafil citrate exposure ( 2.4 , 7.4 , 12.3 ) Ritonavir: Do not exceed a maximum single dose of 25 mg in a 48 hour period ( 2.4 , 5.6 ) Erythromycin or strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, saquinavir): Consider a starting dose of 25 mg ( 2.4 , 7.4 ) 7.1 Nitrates Administration of sildenafil tablets with nitric oxide donors such as organic nitrates or organic nitrites in any form is contraindicated. Stronger CYP3A4 inhibitors such as ketoconazole or itraconazole could be expected to have greater effects than seen with saquinavir. A starting dose of 25 mg of sildenafil tablets should be considered in patients taking erythromycin or strong CYP3A4 inhibitors (such as saquinavir, ketoconazole, itraconazole) [ see Dosage and Administration ( 2.4 ), Clinical Pharmacology ( 12.3 ) ] .

Avoid use of sildenafil with other PDE-5 inhibitors such as Viagra.

Administration of sildenafil with nitrates is contraindicated. Sildenafil potentiates the hypotensive effects of nitrates.

Sildenafil is contraindicated with organic nitrites due to potentiation of hypotensive effects through the nitric oxide/cGMP pathway.

PDE-5 inhibitor that potentiates hypotensive effects of nitroglycerin. Contraindicated with nitroglycerin.

PDE5 inhibitor that potentiates hypotensive effects of nitroglycerin. Concomitant use is contraindicated.

PDE-5 inhibitor that potentiates hypotensive effects of nitroglycerin. Concomitant use is contraindicated.

Co-administration with sildenafil is contraindicated because of hypotension. Do not administer within 24 hours of sildenafil.

7 DRUG INTERACTIONS Sildenafil citrate can potentiate the hypotensive effects of nitrates, alpha blockers, and anti-hypertensives ( 4.1 , 5.5 , 7.1 , 7.2 , 7.3 , 12.2 ) With concomitant use of alpha blockers, initiate sildenafil citrate at 25 mg dose ( 2.3 ) CYP3A4 inhibitors (e.g., ritonavir, ketoconazole, itraconazole, erythromycin): Increase sildenafil citrate exposure ( 2.4 , 7.4 , 12.3 ) Ritonavir: Do not exceed a maximum single dose of 25 mg in a 48 hour period ( 2.4 , 5.6 ) Erythromycin or strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, saquinavir): Consider a starting dose of 25 mg ( 2.4 , 7.4 ) 7.1 Nitrates Administration of sildenafil tablets with nitric oxide donors such as organic nitrates or organic nitrites in any form is contraindicated. 7.4 Ritonavir and other CYP3A4 Inhibitors Co-administration of ritonavir, a strong CYP3A4 inhibitor, greatly increased the systemic exposure of sildenafil (11-fold increase in AUC).

7 DRUG INTERACTIONS Sildenafil citrate can potentiate the hypotensive effects of nitrates, alpha blockers, and anti-hypertensives ( 4.1 , 5.5 , 7.1 , 7.2 , 7.3 , 12.2 ) With concomitant use of alpha blockers, initiate sildenafil citrate at 25 mg dose ( 2.3 ) CYP3A4 inhibitors (e.g., ritonavir, ketoconazole, itraconazole, erythromycin): Increase sildenafil citrate exposure ( 2.4 , 7.4 , 12.3 ) Ritonavir: Do not exceed a maximum single dose of 25 mg in a 48 hour period ( 2.4 , 5.6 ) Erythromycin or strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, saquinavir): Consider a starting dose of 25 mg ( 2.4 , 7.4 ) 7.1 Nitrates Administration of sildenafil tablets with nitric oxide donors such as organic nitrates or organic nitrites in any form is contraindicated. Co-administration of saquinavir, a strong CYP3A4 inhibitor, resulted in 140% and 210% increases in sildenafil C max and AUC, respectively. Stronger CYP3A4 inhibitors such as ketoconazole or itraconazole could be expected to have greater effects than seen with saquinavir.

Avoid concomitant use of sildenafil tablets with Viagra or other PDE-5 inhibitors.

Potential additive blood pressure-lowering effects. Initiate sildenafil at 25 mg dose and ensure patients are stable on alpha-blocker therapy prior to sildenafil initiation.

Use caution with alpha-blockers due to potential additive blood pressure-lowering effects. Initiate sildenafil at lowest dose only after patient is stable on alpha-blocker therapy.

Co-administration causes mean additional reduction of 8 mmHg systolic and 7 mmHg diastolic blood pressure.

PDE5 inhibitor that with silodosin can cause symptomatic hypotension with increased positive orthostatic test results.

Co-administration of sildenafil 50 mg with alcohol studied; interaction mentioned but full severity details cut off in provided text.

Monitor for hypotension when sildenafil is co-administered with amlodipine.

Monitor for hypotension when coadministered with amlodipine.

Monitor for hypotension when sildenafil is co-administered with amlodipine.

Sildenafil can potentiate the hypotensive effects of anti-hypertensive agents.

Concomitant use decreases sildenafil exposure. Dose up-titration of sildenafil may be needed when initiating treatment.

Deferasirox may induce CYP3A4 resulting in decreased sildenafil concentration. Monitor for reduced effectiveness.

Alpha-blocker causing additive blood pressure lowering effects with sildenafil, with reports of symptomatic postural hypotension including dizziness and light-headedness.

Increased systemic exposure (AUC) of sildenafil reported; dosage reduction should be considered.

CYP3A4 substrate; caution should be exercised when administering paclitaxel concomitantly.

Both sapropterin and PDE-5 inhibitors may induce vasorelaxation, potentially reducing blood pressure.

PDE-5 inhibitor that with sepiapterin may cause additive vasorelaxation and blood pressure reduction. Monitor blood pressure.

Monitor for hypotension when sildenafil is co-administered with Widaplik.

Monitor for hypotension when sildenafil is coadministered with amlodipine.

Monitor for hypotension when sildenafil is co-administered with amlodipine.

Azithromycin had a modest effect on sildenafil pharmacokinetics. No dosage adjustment recommended.