Details of Drug-Drug Interaction
| Drug General Information (ID: DDIUB4HQ02) | |||||||||
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| Drug Name | Alfuzosin | Drug Info | Tadalafil | Drug Info | |||||
| Drug Type | Small molecule | Small molecule | |||||||
| Therapeutic Class | Antihypertensive Agents | Impotence Agents | |||||||
| Structure | |||||||||
| Mechanism of Alfuzosin-Tadalafil Interaction (Severity Level: Moderate) | |||||||||
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| Additive hypotensive effects Click to Show/Hide Mechanism Graph | |||||||||
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| Drug Name | Alfuzosin | Tadalafil | |||||||
| Mechanism |
Antihypertensive agent Alpha-1 adrenergic receptor Antagonist |
Hypotensive effects Prostacyclin receptor Agonist |
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| Key Mechanism Factor 1 | |||||||||
| Factor Name | Adrenergic receptor alpha-1 | Structure Sequence | |||||||
| Protein Family | G-protein coupled receptor 1 family | ||||||||
| Protein Function |
This alpha-adrenergic receptor mediates its action by association with G proteins that activate a phosphatidylinositol-calcium second messenger system. Its effect is mediated by G(q) and G(11) proteins. Nuclear ADRA1A-ADRA1B heterooligomers regulate phenylephrine(PE)-stimulated ERK signaling in cardiac myocytes.
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| Key Mechanism Factor 2 | |||||||||
| Factor Name | Prostacyclin receptor |
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Structure
Sequence
MADSCRNLTYVRGSVGPATSTLMFVAGVVGNGLALGILSARRPARPSAFAVLVTGLAATDLLGTSFLSPAVFVAYARNSSLLGLARGGPALCDAFAFAMTFFGLASMLILFAMAVERCLALSHPYLYAQLDGPRCARLALPAIYAFCVLFCALPLLGLGQHQQYCPGSWCFLRMRWAQPGGAAFSLAYAGLVALLVAAIFLCNGSVTLSLCRMYRQQKRHQGSLGPRPRTGEDEVDHLILLALMTVVMAVCSLPLTIRCFTQAVAPDSSSEMGDLLAFRFYAFNPILDPWVFILFRKAVFQRLKLWVCCLCLGPAHGDSQTPLSQLASGRRDPRAPSAPVGKEGSCVPLSAWGEGQVEPLPPTQQSSGSAVGTSSKAEASVACSLC
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| Gene Name | PTGIR | ||||||||
| Uniprot ID | PI2R_HUMAN | ||||||||
| KEGG Pathway | hsa:5739 | ||||||||
| Protein Family | G-protein coupled receptor 1 family | ||||||||
| Protein Function |
Receptor for prostacyclin (prostaglandin I2 or PGI2). The activity of this receptor is mediated by G(s) proteins which activate adenylate cyclase.
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| Mechanism Description |
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| Recommended Action | |||||||||
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| Management | Caution is advised if tadalafil is used in combination with alpha blockers. Patients who demonstrate hemodynamic instability on alpha blocker therapy alone are at increased risk of symptomatic hypotension with concomitant use of tadalafil. Therefore, patients should be stable on alpha blocker therapy prior to initiating tadalafil, and tadalafil should be initiated at the lowest recommended dosage. In those patients already on an optimized dosage of tadalafil, alpha blocker therapy should be initiated at the lowest dosage. Clinicians should bear in mind that the safety of tadalafil in combination with alpha blockers may also be affected by other variables such as intravascular volume depletion and use of other antihypertensive medications. The combination of tadalafil and alpha blockers is not recommended for the treatment of benign prostatic hyperplasia (BPH) due to the lack of safety and efficacy data. Patients on alpha blocker therapy for BPH should discontinue the alpha blocker at least one day prior to starting tadalafil for once-daily use in the treatment of BPH. | ||||||||