Safety of Sildenafil in Chronic Kidney Disease
Sildenafil can be safely used in patients with chronic kidney disease (CKD) with appropriate dose adjustments and monitoring, but is absolutely contraindicated when used concomitantly with nitrate medications due to risk of severe hypotension.
Dosing Considerations in CKD
- Sildenafil is highly protein-bound and not significantly eliminated by renal dialysis, so standard supportive measures should be adopted in cases of overdose 1
- For patients with CKD, consider starting with a lower dose (25mg) and titrating based on response and tolerability 2, 3
- Medication review should be performed periodically in CKD patients to assess for potential drug interactions, as polypharmacy is common in this population 4
Absolute Contraindications
- Sildenafil must not be used concomitantly with nitrate medications due to risk of severe hypotension 4
- Patients on sildenafil should avoid taking nitroglycerin for at least 24 hours after sildenafil use (48 hours for tadalafil) 4
Cardiovascular Considerations
- Sildenafil causes modest, transient reductions in blood pressure with negligible effects on heart rate at recommended doses 5
- Sexual activity represents moderate physical activity (3-5 metabolic equivalents), so patients should be assessed for ability to perform this level of activity 4
- Patients with known or suspected coronary artery disease may benefit from exercise testing to determine if resumption of sexual activity with sildenafil is likely to increase risk of myocardial ischemia 5
Safety in Advanced CKD and Dialysis
- Studies in patients with end-stage renal disease (ESRD) on dialysis have shown sildenafil to be generally safe and effective for treating erectile dysfunction 2, 3
- In clinical studies of >260 dialysis patients receiving sildenafil, only six discontinuations due to adverse events were reported (primarily headache) 3
- Mild headache (18%) and flushing (30%) are the most commonly reported side effects in ESRD patients 2
Monitoring Recommendations
- Monitor eGFR, electrolytes, and therapeutic medication levels in CKD patients receiving medications with narrow therapeutic windows or potential adverse effects 4
- Consider GFR when dosing medications cleared by the kidneys 4
- For most clinical settings, validated eGFR equations using serum creatinine are appropriate for drug dosing 4
Potential Adverse Effects
- Rare cases of acute kidney injury have been reported with sildenafil overdose, though renal function typically recovers with supportive care 6
- People with CKD may be more susceptible to nephrotoxic effects of medications, so always consider benefits versus potential harms 4
Special Considerations
- Review and limit use of over-the-counter medicines and dietary/herbal remedies that may be harmful for people with CKD 4
- When prescribing to CKD patients of child-bearing potential, review teratogenicity potential and provide reproductive counseling 4
- In patients with extremes of body weight, eGFR non-indexed for body surface area may be indicated, especially for medications with narrow therapeutic ranges 4
By following these guidelines and monitoring recommendations, sildenafil can be safely used in most patients with CKD while minimizing risks of adverse effects.