Is Opdivo (nivolumab) safe to use with sildenafil (Viagra)?

Safety of Opdivo (Nivolumab) with Sildenafil

Opdivo (nivolumab) can be safely used with sildenafil (Viagra), as there are no known significant drug interactions between these medications, but caution is warranted regarding potential hypotensive effects when sildenafil is used.

Understanding the Medications

• Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor that works by blocking the breakdown of cyclic guanosine monophosphate (cGMP), facilitating smooth muscle relaxation in the corpus cavernosum and enhancing erections during sexual stimulation 1
• Opdivo (nivolumab) is an immune checkpoint inhibitor used in cancer treatment that is not known to have specific interactions with PDE5 inhibitors like sildenafil

Safety Considerations for Sildenafil Use

Cardiovascular Effects

• Sildenafil alone can cause mean peak reductions in systolic/diastolic blood pressure of 10/7 mm Hg that are not dose-related, with no significant change in heart rate 2
• The most common cardiovascular adverse events with sildenafil include headache (16%), flushing (10%), and dizziness (2%), with incidences of hypotension, orthostatic hypotension, and syncope being less than 2% 2

Absolute Contraindications

• The only absolute contraindication for sildenafil is concurrent use of nitrates in any form (e.g., nitroglycerin, isosorbide dinitrate) due to risk of severe hypotension 3
• Patients taking sildenafil should avoid nitroglycerine for at least 24 hours after sildenafil use 3, 4

Use with Antihypertensive Medications

• Retrospective analyses show no significant increase in adverse events or hypotensive episodes when sildenafil is used with common antihypertensive medications (beta blockers, alpha blockers, diuretics, ACE inhibitors, and calcium antagonists) 2

Specific Considerations for Cancer Patients on Opdivo

• Before prescribing sildenafil to patients on Opdivo, physicians should perform a cardiovascular risk assessment, especially for those with known cardiac disease or multiple cardiovascular risk factors 4
• For patients with indeterminate cardiovascular risk, additional vascular disease assessment may be warranted 5
• Patients with recent (less than 6 months) myocardial infarction, unstable angina, stroke, or life-threatening arrhythmias should use sildenafil with caution 4

Dosing Recommendations

• Standard sildenafil dosing begins at 50mg taken when needed, approximately 1 hour before sexual activity, no more than once daily 1
• Lower doses (25mg) may be appropriate for elderly patients, those with hepatic or renal impairment, or patients taking cytochrome P450 enzyme CYP3A4 inhibitors 1
• Consider starting with a lower test dose to identify patients who may be highly sensitive to sildenafil's effects 6

Monitoring and Management

• If severe hypotension occurs after sildenafil use, aggressive fluid resuscitation is the first step, followed by administration of vasoactive drugs if necessary 7
• If unstable angina or myocardial infarction occurs after sildenafil use, treat according to guidelines but without using nitrates 7

Conclusion

While there are no specific contraindications for using Opdivo with sildenafil, patients should be assessed for cardiovascular risk factors and monitored for potential hypotensive effects. The primary safety concern remains the absolute contraindication of combining sildenafil with nitrates.