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Drug Interactions between labetalol and Quinaglute Dura-Tabs

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Moderate

labetalol quiNIDine

Applies to: labetalol and Quinaglute Dura-Tabs (quinidine)

MONITOR: Quinidine may increase serum levels of some oral beta-blockers. The proposed mechanism is inhibition of CYP450 2D6 first-pass metabolism and decreased hepatic clearance of hepatically metabolized beta-blockers. Quinidine and beta-blockers may also have additive negative inotropic effects, which can be beneficial when used to treat atrial fibrillation. However, adverse effects have been reported with quinidine and propranolol.

MANAGEMENT: Patients should be monitored for orthostatic hypotension, cardiac arrhythmias, bradycardia, and heart failure, and beta-blocker dosage should be decreased if necessary.

References

  1. Manolis AS, Estes NA "Orthostatic hypotension due to quinidine and atenolol." Am J Med 82 (1987): 1083-4
  2. Kessler KM, Humphries WC, Black M, Spann JF "Quinidine pharmacokinetics in patients with cirrhosis or receiving propranolol." Am Heart J 96 (1978): 627-35
  3. Loon NR, Wilcox CS, Folger W "Orthostatic hypotension due to quinidine and propranolol." Am J Med 81 (1986): 1101-4
  4. Zhou HH, Wood AJ "Differences in stereoselective disposition of propranolol do not explain sensitivity differences between white and Chinese subjects: correlation between the clearance of (-)- and (+)- propranolol." Clin Pharmacol Ther 47 (1990): 719-23
  5. Dinai Y, Sharir M, Floman NN, Halkin H "Bradycardia induced by interaction between quinidine and ophthalmic timolol." Ann Intern Med 103 (1985): 890-1
  6. Fenster P, Perrier D, Mayersohn M, Marcus FI "Kinetic evaluation of the propranolol-quinidine combination." Clin Pharmacol Ther 27 (1980): 450-3
  7. Zhou HH, Anthony LB, Roden DM, Wood AJ "Quinidine reduces clearance of (+)-propranolol more than (-)-propranolol through marked reduction in 4-hydroxylation." Clin Pharmacol Ther 47 (1990): 686-93
  8. Ochs HR, Greenblatt DJ, Woo E, et al. "Effect of propranolol on pharmacokinetics and acute electrocardiographic changes following intravenous quinidine in humans." Pharmacology 17 (1978): 301-6
  9. Leemann T, Dayer P, Meyer UA "Single-dose quinidine treatment inhibits metoprolol oxidation in extensive metabolizers." Eur J Clin Pharmacol 29 (1986): 739-41
  10. Dorian P, Newman D, Berman N, Hardy J, Mitchell J "Sotalol and type IA drugs in combination prevent recurrence of sustained ventricular tachycardia." J Am Coll Cardiol 22 (1993): 106-13
  11. Edeki TI, He H, Wood AJ "Pharmacogenetic explanation for excessive B-blockade following timolol eye drops." JAMA 274 (1995): 1611-3
View all 11 references

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Drug and food interactions

Moderate

quiNIDine food

Applies to: Quinaglute Dura-Tabs (quinidine)

GENERALLY AVOID: In a small, randomized, crossover study, the administration of quinidine with grapefruit juice (compared to water) to healthy volunteers significantly prolonged the time to reach peak plasma quinidine concentrations and decreased the plasma concentrations of its major metabolite, 3-hydroxyquinidine. These changes were associated pharmacodynamically with both a delay and a reduction in the maximal effect on QTc interval. The proposed mechanism is delay of gastric emptying as well as inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruits.

MANAGEMENT: Given the drug's narrow therapeutic index, patients receiving quinidine therapy should avoid the consumption of grapefruits and grapefruit juice to prevent any undue fluctuations in plasma drug levels.

References

  1. Ace LN, Jaffe JM, Kunka RL "Effect of food and an antacid on quinidine bioavailability." Biopharm Drug Dispos 4 (1983): 183-90
  2. Min DI, Ku YM, Geraets DR, Lee HC "Effect of grapefruit juice on the pharmacokinetics and pharmacodynamics of quinidine in healthy volunteers." J Clin Pharmacol 36 (1996): 469-76
  3. Ha HR, Chen J, Leuenberger PM, Freiburghaus AU, Follah F "In vitro inhibition of midazolam and quinidine metabolism by flavonoids." Eur J Clin Pharmacol 48 (1995): 367-71
  4. Bailey DG, Dresser GR, Kreeft JH, Munoz C, Freeman DJ, Bend JR "Grapefruit-felodipine interaction: Effect of unprocessed fruit and probable active ingredients." Clin Pharmacol Ther 68 (2000): 468-77
View all 4 references

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Moderate

labetalol food

Applies to: labetalol

MONITOR: Many psychotherapeutic and CNS-active agents (e.g., anxiolytics, sedatives, hypnotics, antidepressants, antipsychotics, opioids, alcohol, muscle relaxants) exhibit hypotensive effects, especially during initiation of therapy and dose escalation. Coadministration with antihypertensives and other hypotensive agents, in particular vasodilators and alpha-blockers, may result in additive effects on blood pressure and orthostasis.

MANAGEMENT: Caution and close monitoring for development of hypotension is advised during coadministration of these agents. Some authorities recommend avoiding alcohol in patients receiving vasodilating antihypertensive drugs. Patients should be advised to avoid rising abruptly from a sitting or recumbent position and to notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia.

References

  1. Sternbach H "Fluoxetine-associated potentiation of calcium-channel blockers." J Clin Psychopharmacol 11 (1991): 390-1
  2. Shook TL, Kirshenbaum JM, Hundley RF, Shorey JM, Lamas GA "Ethanol intoxication complicating intravenous nitroglycerin therapy." Ann Intern Med 101 (1984): 498-9
  3. Feder R "Bradycardia and syncope induced by fluoxetine." J Clin Psychiatry 52 (1991): 139
  4. Ellison JM, Milofsky JE, Ely E "Fluoxetine-induced bradycardia and syncope in two patients." J Clin Psychiatry 51 (1990): 385-6
  5. Rodriguez de la Torre B, Dreher J, Malevany I, et al. "Serum levels and cardiovascular effects of tricyclic antidepressants and selective serotonin reuptake inhibitors in depressed patients." Ther Drug Monit 23 (2001): 435-40
  6. Cerner Multum, Inc. "Australian Product Information." O 0
  7. Pacher P, Kecskemeti V "Cardiovascular side effects of new antidepressants and antipsychotics: new drugs, old concerns?" Curr Pharm Des 10 (2004): 2463-75
  8. Andrews C, Pinner G "Postural hypotension induced by paroxetine." BMJ 316 (1998): 595
View all 8 references

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Moderate

labetalol food

Applies to: labetalol

ADJUST DOSING INTERVAL: Concurrent administration with calcium salts may decrease the oral bioavailability of atenolol and possibly other beta-blockers. The exact mechanism of interaction is unknown. In six healthy subjects, calcium 500 mg (as lactate, carbonate, and gluconate) reduced the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of atenolol (100 mg) by 51% and 32%, respectively. The elimination half-life increased by 44%. Twelve hours after the combination, beta-blocking activity (as indicated by inhibition of exercise tachycardia) was reduced compared to that with atenolol alone. However, during a 4-week treatment in six hypertensive patients, there was no difference in blood pressure values between treatments. The investigators suggest that prolongation of the elimination half-life induced by calcium coadministration may have led to atenolol cumulation during long-term dosing, which compensated for the reduced bioavailability.

MANAGEMENT: It may help to separate the administration times of beta-blockers and calcium products by at least 2 hours. Patients should be monitored for potentially diminished beta-blocking effects following the addition of calcium therapy.

References

  1. Kirch W, Schafer-Korting M, Axthelm T, Kohler H, Mutschler E "Interaction of atenolol with furosemide and calcium and aluminum salts." Clin Pharmacol Ther 30 (1981): 429-35

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Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

See also

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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
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 interaction information available.

Further information

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