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Drug interactions between amlodipine and Cialis

Results for the following 2 drugs:
amlodipine
Cialis (tadalafil)

Interactions between your drugs

Minor

amlodipine ↔ tadalafil

Applies to:amlodipine and Cialis (tadalafil)

Based on their pharmacology, phosphodiesterase-5 (PDE5) inhibitors may conceivably potentiate the hypotensive effect of antihypertensive medications. These agents inhibit PDE5-mediated degradation of cyclic guanosine monophosphate (cGMP), which in vascular smooth muscles can cause peripheral vasodilation. However, clinical pharmacology studies of tadalafil (administered as a 10 mg dose except in studies with angiotensin II receptor (AR) blockers and amlodipine, which used a dose of 20 mg) have demonstrated no clinically significant interaction with various antihypertensive drugs from major classes including calcium channel blockers, ACE inhibitors, beta blockers, thiazide diuretics, and AR blockers. Tadalafil 10 mg and 20 mg also had no clinically significant effect on blood pressure changes due to tamsulosin, an alpha-1a blocker. In addition, analysis of data from Phase 3 clinical trials showed no difference in adverse events in patients taking tadalafil with or without antihypertensive medications. In patients receiving concomitant antihypertensive medications, tadalafil 20 mg may induce a blood pressure decrease that is, in general, minor and not likely to be clinically relevant. In a clinical study of healthy male subjects 45 to 78 years of age, administration of silodosin with a single 20 mg dose of tadalafil resulted in increased frequency of positive orthostatic test results during a 12-hour period following concomitant dosing compared to administration with placebo. No events of symptomatic orthostasis or dizziness were reported in subjects receiving silodosin with tadalafil. Nevertheless, patients should be advised of the potential for interaction and to contact their doctor if they experience symptoms of hypotension such as dizziness, lightheadedness, or fainting.

References

  1. "Product Information. Cialis (tadalafil)." Lilly, Eli and Company, Indianapolis, IN.
  2. "Product Information. Rapaflo (silodosin)." Watson Pharmaceuticals, Corona, CA.

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Drug and food interactions

Moderate

tadalafil food

Applies to: Cialis (tadalafil)

GENERALLY AVOID: Additive hypotensive effects may occur when phosphodiesterase-5 (PDE5) inhibitors such as tadalafil are used with alcohol, as both are mild systemic vasodilators. In clinical pharmacology studies, more subjects administered alcohol at a dose of 0.7 g/kg (equivalent to approximately 6 ounces of 80-proof vodka in an 80-kg male; consumed within 10 minutes in study subjects, providing blood alcohol levels of 0.08%) in combination with tadalafil 10 or 20 mg single doses had clinically significant decreases in blood pressure than with alcohol alone. There were reports of postural dizziness, and orthostatic hypotension was observed in some. When tadalafil 20 mg was administered with alcohol at a lower dose of 0.6 g/kg (equivalent to approximately 4 ounces of 80-proof vodka in an 80-kg male), orthostatic hypotension was not observed, dizziness occurred with similar frequency relative to alcohol alone, and the hypotensive effects of alcohol were not potentiated. Neither tadalafil nor alcohol affected the plasma concentrations of the other.

GENERALLY AVOID: Coadministration with grapefruit juice is likely to increase the plasma concentrations of tadalafil, which is primarily metabolized by CYP450 3A4. However, the interaction has not been studied. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit.

MANAGEMENT: Patients taking tadalafil should avoid consuming large amounts of alcohol, which may increase the potential for orthostatic signs and symptoms including increase in heart rate, decrease in standing blood pressure, dizziness, and headache. It may also be appropriate to avoid consuming large amounts of grapefruit juice.

References

  1. "Product Information. Cialis (tadalafil)." Lilly, Eli and Company, Indianapolis, IN.
  2. "Product Information. Adcirca (tadalafil)." United Therapeutics Corporation, Silver Spring, MD.

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Minor

amlodipine food

Applies to: amlodipine

The consumption of grapefruit juice may slightly increase plasma concentrations of amlodipine. The mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. Data have been conflicting and the clinical significance is unknown. Monitoring for calcium channel blocker adverse effects (e.g., headache, hypotension, syncope, tachycardia, edema) is recommended.

References

  1. Kane GC, Lipsky JJ "Drug-grapefruit juice interactions." Mayo Clin Proc 75 (2000): 933-42
  2. Josefsson M, Zackrisson AL, Ahlner J "Effect of grapefruit juice on the pharmacokinetics of amlodipine in healthy volunteers." Eur J Clin Pharmacol 51 (1996): 189-93
  3. Bailey DG, Arnold JMO, Spence JD "Grapefruit juice and drugs - how significant is the interaction." Clin Pharmacokinet 26 (1994): 91-8
  4. Vincent J, Harris SI, Foulds G, Dogolo LC, Willavize S, Friedman HL "Lack of effect of grapefruit juice on the pharmacokinetics and pharmacodynamics of amlodipine." Br J Clin Pharmacol 50 (2000): 455-63
  5. Bailey DG, Malcolm J, Arnold O, Spence JD "Grapefruit juice-drug interactions." Br J Clin Pharmacol 46 (1998): 101-10
  6. Josefsson M, Ahlner J "Amlodipine and grapefruit juice." Br J Clin Pharmacol 53 (2002): 405; discussion 406
View all 6 references

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Therapeutic duplication warnings

No therapeutic duplications were found for your selected drugs.

Drug Interaction Classification

The classifications below are a guideline only. The relevance of a particular drug interaction to a specific patient is difficult to determine using this tool alone given the large number of variables that may apply.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No information available.

Do not stop taking any medications without consulting your healthcare provider.

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