Drug interactions
Sepiapterin + Tadalafil
Severity: Moderate
Sepiapterin 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
Sepiapterin increases BH4, which supports nitric oxide synthase activity and may enhance vasodilation. Combined with tadalafil, which prolongs cGMP signalling, this may cause additive blood pressure lowering and symptomatic hypotension.
What this interaction means in plain words
Sepiapterin 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.
Sepiapterin belongs to Miscellaneous; Tadalafil belongs to Genitourinary.
Why it happens
Additive vasodilation through enhanced nitric oxide synthesis (BH4 cofactor) and PDE5 inhibition.
What to do
Monitor blood pressure and symptoms of hypotension such as dizziness or syncope when starting or adjusting either drug. Counsel patients to report lightheadedness, as tadalafil effects are long-lasting.
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 Sepiapterin
- Methotrexate + Sepiapterin Major
- Pemetrexed + Sepiapterin Major
- Sepiapterin + Sulphasalazine Major
- Levodopa + Sepiapterin Moderate
- Sepiapterin + Sildenafil Moderate
- Sepiapterin + Vardenafil Moderate
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
Frequently asked questions
Can I take Sepiapterin with Tadalafil?
MediHelp rates the interaction as moderate. Sepiapterin 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. Sepiapterin increases BH4, which supports nitric oxide synthase activity and may enhance vasodilation. Combined with tadalafil, which prolongs cGMP signalling, this may cause additive blood pressure lowering and symptomatic hypotension.
How serious is the interaction between Sepiapterin 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 and symptoms of hypotension such as dizziness or syncope when starting or adjusting either drug. Counsel patients to report lightheadedness, as tadalafil effects are long-lasting.
What other medicines interact with Sepiapterin?
MediHelp also lists interactions of Sepiapterin with, for example, Methotrexate, Pemetrexed, Sulphasalazine. The full list is on the Sepiapterin page.
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