Drug interactions
Sapropterin + Tadalafil
Severity: Moderate
Sapropterin and Tadalafil: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Sapropterin is a cofactor for nitric oxide synthase and may increase nitric oxide production. Combined with a PDE5 inhibitor this could cause additive vasodilation and low blood pressure.
What this interaction means in plain words
Sapropterin and Tadalafil can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Sapropterin belongs to Miscellaneous; Tadalafil belongs to Genitourinary.
Why it happens
Sapropterin may enhance nitric oxide synthesis while tadalafil prolongs cGMP signalling, a theoretical additive vasodilatory effect.
What to do
Monitor blood pressure when the drugs are started together or doses changed. Counsel patients to report dizziness or fainting.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Tadalafil
- Amyl nitrite + Tadalafil Contraindicated
- Isosorbide dinitrate + Tadalafil Contraindicated
- Isosorbide mononitrate + Tadalafil Contraindicated
- Nitroglycerin po + Tadalafil Contraindicated
- Nitroglycerin rectal + Tadalafil Contraindicated
- Nitroglycerin sublingual + Tadalafil Contraindicated
Other interactions of Sapropterin
- Avanafil + Sapropterin Moderate
- Carbidopa-entacapone-levodopa + Sapropterin Moderate
- Carbidopa-levodopa + Sapropterin Moderate
- Levodopa + Sapropterin Moderate
- Methotrexate + Sapropterin Moderate
- Phenobarbitone + Sapropterin Moderate
Frequently asked questions
Can I take Sapropterin with Tadalafil?
MediHelp rates the interaction as moderate. Sapropterin and Tadalafil can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Sapropterin is a cofactor for nitric oxide synthase and may increase nitric oxide production. Combined with a PDE5 inhibitor this could cause additive vasodilation and low blood pressure.
How serious is the interaction between Sapropterin and Tadalafil?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure when the drugs are started together or doses changed. Counsel patients to report dizziness or fainting.
What other medicines interact with Tadalafil?
MediHelp also lists interactions of Tadalafil with, for example, Amyl nitrite, Isosorbide dinitrate, Isosorbide mononitrate. The full list is on the Tadalafil page.
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