Sildenafil and Tadalafil Interaction

Avoid
Researched 95% confidence

Sildenafil and Tadalafil have a potentially harmful interaction with 95% confidence. Do not combine PDE5 inhibitors. Additive pharmacological effect on cGMP accumulation increases risk of severe hypotension, priapism, and other adverse events with no additional therapeutic benefit. Both compounds affect the blood vessels and gonads, so monitoring these systems is recommended.

Compound Profiles

Sildenafil

PDE5 Inhibitor | Erectile Function & Pulmonary Hypertension

Sildenafil selectively inhibits phosphodiesterase type 5 (PDE5), the enzyme responsible for the hydrolysis and degradation of cyclic guanosine monophosphate (cGMP) in vascular smooth muscle. During sexual arousal, nitric oxide (NO) is released from nerve terminals and endothelial cells in the corpus cavernosum, activating soluble guanylate cyclase and increasing intracellular cGMP concentrations.

Half-life: ~3-5 hours Typical dose: 50mg as-needed (range 25-100mg) pde5, sexual health
epo receptorpde5 blood pressure lowering
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Tadalafil

PDE5 Inhibitor | Erectile Function & Blood Flow

Tadalafil selectively inhibits phosphodiesterase type 5 (PDE5), the enzyme responsible for degrading cyclic guanosine monophosphate (cGMP) in smooth muscle tissue. During sexual stimulation, nitric oxide (NO) is released in the corpus cavernosum, activating guanylate cyclase and increasing cGMP levels.

Half-life: ~17.5 hours Typical dose: 5mg daily or 10-20mg as-needed pde5, sexual health
pde5 blood pressure lowering
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Combined Organ Load

Blood Vessels
low
Gonads
low

Shared Safety Flags

2x 2 compounds share the blood-pressure-lowering safety flag (Sildenafil, Tadalafil). Monitor accordingly.

Frequently Asked Questions

Can I take Sildenafil with Tadalafil?

Combining Sildenafil with Tadalafil is not recommended. Do not combine PDE5 inhibitors. Additive pharmacological effect on cGMP accumulation increases risk of severe hypotension, priapism, and other adverse events with no additional therapeutic benefit.

Is Sildenafil and Tadalafil safe together?

This combination carries significant risk. Do not combine PDE5 inhibitors. Additive pharmacological effect on cGMP accumulation increases risk of severe hypotension, priapism, and other adverse events with no additional therapeutic benefit. Consult a healthcare professional before combining.

What are the interactions between Sildenafil and Tadalafil?

Do not combine PDE5 inhibitors. Additive pharmacological effect on cGMP accumulation increases risk of severe hypotension, priapism, and other adverse events with no additional therapeutic benefit. This assessment has 95% confidence and is based on documented research data.

How should I time Sildenafil and Tadalafil?

Sildenafil has a half-life of ~3-5 hours and Tadalafil has a half-life of ~17.5 hours. No specific timing requirements identified for this combination, but separating administration can help monitor individual effects.

Check this pair in the full Interaction Checker Full comparison: Sildenafil vs Tadalafil

This interaction analysis is compiled from research literature and pharmacological mechanism data. Always consult a healthcare professional before combining compounds.