Meta Information
ID:daily-low-dose-tadalafil
Name:
Schema Version:2.4_uniform_evidence_2026_06_18
Created
2026-05-10T18:49:08.825488Z
Model
Gemini 3.1 Pro (High)
Interactions
Target id:
/class/pde5-inhibitors
Target name:
PDE5 Inhibitors
Severity:
major
Interaction type:
contraindication
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Using two drugs from the same class is redundant and dangerously increases risk of side effects.
Actionable advice:
This should never be combined with other PDE5 inhibitors.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
( 5.4 ) Concomitant PDE5 inhibitors: Avoid use with CIALIS or other PDE5 inhibitors.
Label source:
FDA label: Tadalafil
Action type:
avoid
Target id:
/dietary/grapefruit-pomelo
Target name:
Grapefruit, Pomelo, and Seville Oranges
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Grapefruit blocks the enzyme that breaks down tadalafil, increasing drug levels and side effects.
Actionable advice:
Grapefruit products should be strictly avoided.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Although specific interactions have not been studied, other CYP3A inhibitors, such as erythromycin, itraconazole, and grapefruit juice, would likely increase tadalafil exposure.
Label source:
FDA label: Tadalafil
Action type:
avoid
Target id:
/intervention/saint-johns-wort
Target name:
Saint John's Wort
Severity:
major
Interaction type:
diminishing
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
St. John's Wort speeds up tadalafil's breakdown, significantly reducing its effectiveness.
Actionable advice:
These should not be taken together.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Potent Inducers of CYP3A For patients chronically taking potent inducers of CYP3A, such as rifampin, avoid use of tadalafil [see Clinical Pharmacology (12.3) ] .
Label source:
FDA label: Tadalafil
Action type:
avoid
Target id:
/class/ace-inhibitors
Target name:
ACE Inhibitors
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Taking with blood pressure medications like ACE inhibitors can cause an excessive drop in blood pressure.
Actionable advice:
Blood pressure should be monitored closely.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
(7.4) • Lithium: Symptoms of lithium toxicity (7.5) • Gold: Nitritoid reactions have been reported (7.6) Initiation of Lisinopril in patients on diuretics may result in excessive reduction of blood pressure.
Label source:
FDA label: Lisinopril (target-side evidence)
Action type:
monitor
Target id:
/intervention/amlodipine
Target name:
Amlodipine
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Taking with blood pressure medications like amlodipine can cause an excessive drop in blood pressure.
Actionable advice:
Blood pressure should be monitored closely.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
When NORVASC and sildenafil were used in combination, each agent independently exerted its own blood pressure lowering effect. 7.6 Atorvastatin Co-administration of multiple 10 mg doses of NORVASC with 80 mg of atorvastatin resulted in no significant change in the steady-state pharmacokinetic parameters of atorvastatin. 7.7 Digoxin Co-administration of NORVASC with digoxin did not change serum dig
Label source:
FDA label: Amlodipine (target-side evidence)
Action type:
monitor
Target id:
/class/arbs
Target name:
Angiotensin Receptor Blockers (ARBs)
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Taking with blood pressure medications like ARBs can cause an excessive drop in blood pressure.
Actionable advice:
Blood pressure should be monitored closely.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
discontinue the drug, taking into account the importance of the drug to the mother. 8.4 Pediatric Use Neonates with a history of in utero exposure to telmisartan tablets USP: If oliguria or hypotension occurs, direct attention toward support of blood pressure and renal perfusion.
Label source:
FDA label: Telmisartan (target-side evidence)
Action type:
monitor
Target id:
/intervention/metoprolol
Target name:
Metoprolol
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Taking with blood pressure medications like metoprolol can cause an excessive drop in blood pressure.
Actionable advice:
Blood pressure should be monitored closely.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
to the attenuation of beta-mediated vasodilatation in skeletal muscle. 5.6 Major Surgery Avoid initiation of a high-dose regimen of extended-release metoprolol in patients undergoing non-cardiac surgery, since such use in patients with cardiovascular risk factors has been associated with bradycardia, hypotension, stroke, and death.
Label source:
FDA label: Metoprolol (target-side evidence)
Action type:
monitor
Target id:
/class/mtor-inhibitors
Target name:
mTOR Inhibitors
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Tadalafil can affect the metabolism of mTOR inhibitors, potentially altering their levels and toxicity risk.
Actionable advice:
Requires specialist dose management.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Metabolism Sirolimus is a substrate for both CYP3A4 and P-gp.
Label source:
FDA label: Sirolimus (target-side evidence)
Action type:
informational_none
Target id:
/intervention/nebivolol
Target name:
Nebivolol
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Taking with blood pressure medications like nebivolol can cause an excessive drop in blood pressure.
Actionable advice:
Blood pressure should be monitored closely.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Abrupt withdrawal of β-blockers may be followed by an exacerbation of the symptoms of hyperthyroidism or may precipitate a thyroid storm. 5.7 Peripheral Vascular Disease β-blockers can precipitate or aggravate symptoms of arterial insufficiency in patients with peripheral vascular disease. 5.8 Non-dihydropyridine Calcium Channel Blockers Because of significant negative inotropic and chronotropic e
Label source:
FDA label: Nebivolol (target-side evidence)
Action type:
monitor
Target id:
/intervention/propranolol
Target name:
Propranolol
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Taking with blood pressure medications like propranolol can cause an excessive drop in blood pressure.
Actionable advice:
Blood pressure should be monitored closely.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
7.3 Antihypertensives PDE5 inhibitors, including tadalafil, are mild systemic vasodilators.
Label source:
FDA label: Tadalafil §7.3 Antihypertensives
Action type:
monitor
Target id:
/intervention/beetroot-juice
Target name:
Beetroot Juice
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Beetroot contains nitrates that, combined with tadalafil, can cause a significant drop in blood pressure.
Actionable advice:
Blood pressure should be monitored carefully.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Tadalafil tablets potentiate the hypotensive effect of nitrates.
Label source:
FDA label: Tadalafil §7.3 Antihypertensives; corroborated by NatMed Pro: Beet Monograph (dietary nitrate)
Action type:
monitor
Target id:
/class/sglt2-inhibitors
Target name:
SGLT2 Inhibitors
Severity:
major
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
These diabetes drugs increase urination and can lower blood pressure, adding to tadalafil's effects.
Actionable advice:
Blood pressure and hydration should be monitored closely.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
ing infection requiring urgent surgical intervention, have been identified in postmarketing surveillance in patients with diabetes mellitus receiving SGLT2 inhibitors, including dapagliflozin tablets.
Label source:
FDA label: Dapagliflozin (target-side evidence)
Action type:
monitor
Target id:
/class/glp-1-receptor-agonists
Target name:
GLP-1 Receptor Agonists
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
These diabetes drugs can lower blood pressure, adding to tadalafil's effect and increasing dizziness risk.
Actionable advice:
Blood pressure should be monitored.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
In patients with type 2 diabetes, the average semaglutide blood concentrations following administration of WEGOVY 25 mg tablets once daily were lower than the average semaglutide blood concentrations following use of WEGOVY 2.4 mg injection once weekly [see Clinical Pharmacology (12.3)].
Label source:
FDA label: Semaglutide (target-side evidence)
Action type:
monitor
Target id:
/dietary/alcohol-acute
Target name:
Alcohol (Acute Consumption)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Alcohol can increase the blood pressure-lowering effects of tadalafil, causing dizziness or fainting.
Actionable advice:
Alcohol intake is best limited.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
in blood pressure occurred following coadministration of tadalafil with these agents compared with placebo [see Clinical Pharmacology (12.2) ] . 7.4 Alcohol Both alcohol and tadalafil, a PDE5 inhibitor, act as mild vasodilators.
Label source:
FDA label: Tadalafil
Action type:
informational_none
Target id:
/intervention/cannabis
Target name:
Cannabis
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Cannabis can also lower blood pressure, potentially leading to dizziness when combined with tadalafil.
Actionable advice:
This is best used with caution.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
The vasodilatory effects of Viagra necessitate caution in its use in patients with cardiovascular disease and it is contraindicated in patients receiving nitrates.
Label source:
PubMed: Clinical cardiology (2002)
Source url:
Exact phrase from label:
Severity of sildenafil-cannabis-related cardiovascular events forces the healthcare professionals to take them into account and considering them in clinical pictures of an ischemic cardiomyopathy hard to classify.
Label source:
PubMed: Revista internacional de andrologia (2020)
Source url:
Exact phrase from label:
This paper reports the case of a young man who presented with a myocardial infarction after taking Viagra in combination with cannabis, a known inhibitor of the cytochrome P450 3A4 isoenzyme.
Label source:
PubMed: Clinical cardiology (2002)
Action type:
informational_none
Target id:
/intervention/milk-thistle
Target name:
Milk Thistle (Silymarin)
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Milk thistle may inhibit tadalafil's breakdown, potentially increasing its levels and side effects.
Actionable advice:
It is worth watching out for increased side effects.
Validation status:
validated_via_pubmed
Evidence tier:
tier_b
Evidence basis:
pubmed_abstract_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Although silymarin does inhibit certain drug-metabolizing enzymes and drug transporters, such effects are unlikely to manifest in clinical settings.
Label source:
PubMed: Molecules (Basel, Switzerland) (2019)
Source url:
Exact phrase from label:
Silibinin, the main component of silymarin (a milk thistle extract used for treatment of liver injury), has been shown to inhibit CYP3A4 in human liver microsomes.
Label source:
PubMed: Planta medica (2007)
Source url:
Exact phrase from label:
Silymarin inhibits the metabolism of losartan to E-3174, with the magnitude of the interaction differing in individuals with different CYP2C9 genotypes.
Label source:
PubMed: European journal of clinical pharmacology (2009)
Action type:
monitor
Target id:
/class/statins
Target name:
Statins
Severity:
moderate
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Some statins and tadalafil use the same enzyme, potentially increasing drug levels and side effects.
Actionable advice:
It is worth watching out for muscle pain or other side effects.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
Potent Inhibitors of CYP3A Tadalafil is metabolized predominantly by CYP3A in the liver.
Label source:
FDA label: Tadalafil (Clinical Pharmacology); corroborated by FDA label: Simvastatin (CYP3A substrate)
Action type:
monitor
Target id:
/intervention/cocoa-flavanols
Target name:
Cocoa Flavanols
Severity:
minor
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Cocoa flavanols can lower blood pressure, which may add to the effects of tadalafil.
Actionable advice:
It is a good idea to check blood pressure if using high doses.
Validation status:
validated_via_primary_literature
Evidence tier:
tier_b
Evidence basis:
primary_literature_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
This review provides moderate-quality evidence that flavanol-rich chocolate and cocoa products cause a small (2 mmHg) blood pressure-lowering effect in mainly healthy adults in the short term.
Label source:
PubMed/primary literature: https://pubmed.ncbi.nlm.nih.gov/28439881/
Action type:
monitor
Target id:
/intervention/niacin
Target name:
Niacin (Vitamin B3)
Severity:
minor
Interaction type:
adverse
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Both can cause flushing (skin redness and warmth); taking them together may worsen this effect.
Actionable advice:
Increased flushing may occur.
Validation status:
unvalidatable
Evidence tier:
tier_e
Evidence basis:
unvalidatable
Evidence anchors:
Source url:
Scientific literature support not found
Exact phrase from label:
Label source:
NatMed Pro: Niacin Monograph
Action type:
informational_none
Target id:
/intervention/theophylline
Target name:
Theophylline
Severity:
minor
Interaction type:
diminishing
Nature:
absolute
Temporal spacing:
Hours before target:
0
Hours after target:
0
Description:
Tadalafil may slightly increase the breakdown of theophylline, potentially reducing its effectiveness.
Actionable advice:
Generally no action needed.
Validation status:
validated_via_fda_label
Evidence tier:
tier_a
Evidence basis:
fda_label_verbatim
Evidence anchors:
Source url:
Exact phrase from label:
owing co-administration with tadalafil are shown in Figure 3. a A small augmentation (increase of 3 beats per minute) in heart rate was observed with theophylline. b Tadalafil (40 mg qd) had no clinically significant effect on exposure (AUC and C max ) of bosentan metabolites. c 95% CI Figure 3: Impact of Tadalafil on the Pharmacokinetics of Other Drugs Figure 2 Figure 3
Label source:
FDA label: Tadalafil
Action type:
informational_none