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Drug Interactions between felodipine and itraconazole

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

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Major

itraconazole felodipine

Applies to: itraconazole and felodipine

CONTRAINDICATED: Coadministration with itraconazole or ketoconazole may significantly increase the plasma concentrations of felodipine. The proposed mechanism is decreased first-pass metabolism and hepatic clearance of felodipine due to inhibition of CYP450 3A4. In nine healthy volunteers, administration of a single 5 mg oral dose of felodipine following pretreatment with itraconazole 200 mg once daily for 4 days resulted in average increases of nearly 8-fold in felodipine peak plasma concentration (Cmax), 6-fold in systemic exposure (AUC), and 2-fold in elimination half-life compared to administration with placebo. The decreases in blood pressure and increases in heart rate were also significantly greater with itraconazole. Although not studied, ketoconazole and levoketoconazole are expected to interact similarly, since they are known potent inhibitors of CYP450 3A4.

There have been case reports of leg and ankle edema in patients treated with itraconazole and dihydropyridine calcium channel blockers. Pharmacodynamically, itraconazole exhibits a dose-related negative inotropic effect, which may be additive to those of calcium channel blockers (CCBs). It is conceivable that coadministration may potentiate the risk of ventricular dysfunction, congestive heart failure, and peripheral and pulmonary edema, particularly in patients with preexisting risk factors (e.g., a history of congestive heart failure; cardiac disease such as ischemic and valvular disease; significant pulmonary disease such as chronic obstructive pulmonary disorder; edematous disorders such as renal failure). Itraconazole alone has also been associated with postmarketing reports of congestive heart failure, peripheral edema, and pulmonary edema in patients treated for onychomycosis and/or systemic fungal infections. Heart failure was more frequently reported in patients receiving a dosage of 400 mg/day, although there were also cases reported among those receiving lower daily dosages.

MANAGEMENT: Because the alterations in felodipine pharmacokinetics cannot be feasibly managed by dosage reduction, concomitant use with itraconazole or ketoconazole is considered contraindicated. Some authorities state that coadministration with felodipine is considered contraindicated during and for 2 weeks after treatment with itraconazole (AU).

References (7)
  1. (2001) "Product Information. Nizoral (ketoconazole)." Janssen Pharmaceuticals, 1992
  2. (2002) "Product Information. Sporanox (itraconazole)." Janssen Pharmaceuticals
  3. Rosen T (1994) "Debilitating edema associated with itraconazole therapy." Arch Dermatol, 130, p. 260-1
  4. Neuvonen PJ, Suhonen R (1995) "Itraconazole interacts with felodipine." J Am Acad Dermatol, 33, p. 134-5
  5. Tailor SAN, Gupta AK, Walker SE, Shear NH (1996) "Peripheral edema due to nifedipine-itraconazole interaction: a case report." Arch Dermatol, 132, p. 350-2
  6. Tailor SAN (1996) "Peripheral edema due to nifedipine-itraconazole interaction: a case report." Arch Dermatol, 132, p. 1374
  7. Jalava KM, Olkkola KT, Neuvonen PJ (1997) "Itraconazole greatly increases plasma concentrations and effects of felodipine." Clin Pharmacol Ther, 61, p. 410-5

Drug and food interactions

Moderate

itraconazole food

Applies to: itraconazole

ADJUST DOSING INTERVAL: Food increases the absorption of itraconazole capsules but decreases the absorption of itraconazole oral solution. Cola beverages may increase the bioavailability of itraconazole capsules. Itraconazole capsules require an acidic gastric pH for adequate dissolution and subsequent absorption. Cola beverages help lower gastric pH and improve absorption.

GENERALLY AVOID: Grapefruit juice may impair the absorption of itraconazole capsules, resulting in decreased antifungal effects. In a small, randomized, crossover study, the administration of itraconazole capsules with double-strength grapefruit juice (compared to water) was associated with significantly decreased (43%) plasma concentrations of itraconazole and its pharmacologically active hydroxy metabolite, as well as delayed times to reach peak concentrations of both. The exact mechanism of interaction is unknown but may involve reduced absorption of itraconazole secondary to enhanced activity of intestinal P-glycoprotein drug efflux pumps and delayed gastric emptying induced by certain compounds present in grapefruits. Another study reported no pharmacokinetic changes with single-strength grapefruit juice. Whether or not these observations apply to itraconazole oral solution is unknown.

MANAGEMENT: The manufacturer recommends that the capsules be taken immediately after a full meal and the solution be taken on an empty stomach to ensure maximal absorption. Cola beverages may help increase the bioavailability of itraconazole capsules, particularly in patients with hypochlorhydria or those treated concomitantly with gastric acid suppressants. Until more information is available, it may be advisable to avoid the consumption of grapefruits and grapefruit juice during itraconazole therapy.

References (10)
  1. Van Peer A, Woestenborghs R, Heykants J, et al. (1989) "The effects of food and dose on the oral systemic availability of itraconazole in healthy subjects." Eur J Clin Pharmacol, 36, p. 423-6
  2. Wishart JM (1987) "The influence of food on the pharmacokinetics of itraconazole in patients with superficial fungal infection." J Am Acad Dermatol, 17, p. 220-3
  3. (2002) "Product Information. Sporanox (itraconazole)." Janssen Pharmaceuticals
  4. Barone JA, Koh JG, Bierman RH, Colaizzi JL, Swanson KA, Gaffar MC, Moskovitz BL, Mechlinski W, Van de Velde V (1993) "Food interaction and steady-state pharmacokinetics of itraconazole capsules in healthy male volunteers." Antimicrob Agents Chemother, 37, p. 778-84
  5. Zimmermann T, Yeates RA, Albrecht M, Laufen H, Wildfeuer A (1994) "Influence of concomitant food intake on the gastrointestinal absorption of fluconazole and itraconazole in japanese subjects." Int J Clin Pharmacol Res, 14, p. 87-93
  6. (2022) "Product Information. Sporanox (itraconazole)." Janssen Pharmaceuticals
  7. Kawakami M, Suzuki K, Ishizuka T, Hidaka T, Matsuki Y, Nakamura H (1998) "Effect of grapefruit juice on pharmacokinetics of itraconazole in healthy subjects." Int J Clin Pharmacol Ther, 36, p. 306-8
  8. Barone JA, Moskotitz BL, Guarnieri J, Hassell AE, Colaizzi JL, Bierman RH, Jessen L (1998) "Food interaction and steady-state pharmacokinetics of itraconazole oral solution in healthy volunteers." Pharmacotherapy, 18, p. 295-301
  9. Penzak SR, Gubbins PO, Gurley BJ, Wang PL, Saccente M (1999) "Grapefruit juice decreases the systemic availability of itraconazole capsules in healthy volunteers." Ther Drug Monit, 21, p. 304-9
  10. Katz HI (1999) "Drug interactions of the newer oral antifungal agents." Br J Dermatol, 141, p. 26-32
Moderate

felodipine food

Applies to: felodipine

GENERALLY AVOID: The consumption of grapefruit juice may be associated with significantly increased plasma concentrations of some calcium channel blockers (CCBs) when they are administered orally. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. The interaction has been reported with the dihydropyridine CCBs (in roughly decreasing order of magnitude) felodipine, nisoldipine, nifedipine, and nimodipine, often with a high degree of interindividual variability. Grapefruit juice caused more than twofold increases in felodipine, nifedipine, and nisoldipine AUCs.

MANAGEMENT: The manufacturers of nifedipine and nisoldipine recommend avoiding grapefruit juice. Patients treated orally with other calcium channel blockers should be advised to avoid consumption of large amounts of grapefruits and grapefruit juice to prevent any undue fluctuations in serum drug levels. Increased effects on blood pressure may persist for up to 4 days after the consumption of grapefruit juice. Monitoring for calcium channel blocker adverse effects (e.g., headache, hypotension, syncope, tachycardia, edema) is recommended.

References (19)
  1. Edgar B, Bailey D, Bergstrand R, Johnsson G, Regardh CG (1992) "Acute effects of drinking grapefruit juice on the pharmacokinetics and dynamics of felodipine--and its potential clinical relevance." Eur J Clin Pharmacol, 42, p. 313-7
  2. (2002) "Product Information. Plendil (felodipine)." Merck & Co., Inc
  3. (2002) "Product Information. Procardia (nifedipine)." Pfizer U.S. Pharmaceuticals
  4. Bailey DG, Arnold JM, Munoz C, Spence JD (1993) "Grapefruit juice--felodipine interaction: mechanism, predictability, and effect of naringin." Clin Pharmacol Ther, 53, p. 637-42
  5. Bailey DG, Arnold JMO, Spence JD (1994) "Grapefruit juice and drugs - how significant is the interaction." Clin Pharmacokinet, 26, p. 91-8
  6. Bailey DG, Arnold JM, Strong HA, Munoz C, Spence JD (1993) "Effect of grapefruit juice and naringin on nisoldipine pharmacokinetics." Clin Pharmacol Ther, 54, p. 589-94
  7. Yamreudeewong W, Henann NE, Fazio A, Lower DL, Cassidy TG (1995) "Drug-food interactions in clinical practice." J Fam Pract, 40, p. 376-84
  8. (1995) "Grapefruit juice interactions with drugs." Med Lett Drugs Ther, 37, p. 73-4
  9. (2001) "Product Information. Sular (nisoldipine)." Astra-Zeneca Pharmaceuticals
  10. Josefsson M, Zackrisson AL, Ahlner J (1996) "Effect of grapefruit juice on the pharmacokinetics of amlodipine in healthy volunteers." Eur J Clin Pharmacol, 51, p. 189-93
  11. Bailey DG, Malcolm J, Arnold O, Spence JD (1998) "Grapefruit juice-drug interactions." Br J Clin Pharmacol, 46, p. 101-10
  12. Bailey DG, Kreeft JH, Munoz C, Freeman DJ, Bend JR (1998) "Grapefruit juice felodipine interaction: Effect of naringin and 6',7'-dihydroxybergamottin in humans." Clin Pharmacol Ther, 64, p. 248-56
  13. Fuhr U, Maier-Bruggemann A, Blume H, et al. (1998) "Grapefruit juice increases oral nimodipine bioavailability." Int J Clin Pharmacol Ther, 36, p. 126-32
  14. Gunston GD, Mehta U (2000) "Potentially serious drug interactions with grapefruit juice." S Afr Med J, 90, p. 41
  15. Takanaga H, Ohnishi A, Maatsuo H, et al. (2000) "Pharmacokinetic analysis of felodipine-grapefruit juice interaction based on an irreversible enzyme inhibition model." Br J Clin Pharmacol, 49, p. 49-58
  16. Bailey DG, Dresser GR, Kreeft JH, Munoz C, Freeman DJ, Bend JR (2000) "Grapefruit-felodipine interaction: Effect of unprocessed fruit and probable active ingredients." Clin Pharmacol Ther, 68, p. 468-77
  17. Ho PC, Ghose K, Saville D, Wanwimolruk S (2000) "Effect of grapefruit juice on pharmacokinetics and pharmacodynamics of verapamil enantiomers in healthy volunteers." Eur J Clin Pharmacol, 56, p. 693-8
  18. Fuhr U, Muller-Peltzer H, Kern R, et al. (2002) "Effects of grapefruit juice and smoking on verapamil concentrations in steady state." Eur J Clin Pharmacol, 58, p. 45-53
  19. Cerner Multum, Inc. "UK Summary of Product Characteristics."
Moderate

felodipine food

Applies to: felodipine

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. Patients should also avoid driving or operating hazardous machinery until they know how the medications affect them.

References (10)
  1. Sternbach H (1991) "Fluoxetine-associated potentiation of calcium-channel blockers." J Clin Psychopharmacol, 11, p. 390-1
  2. Shook TL, Kirshenbaum JM, Hundley RF, Shorey JM, Lamas GA (1984) "Ethanol intoxication complicating intravenous nitroglycerin therapy." Ann Intern Med, 101, p. 498-9
  3. Feder R (1991) "Bradycardia and syncope induced by fluoxetine." J Clin Psychiatry, 52, p. 139
  4. Ellison JM, Milofsky JE, Ely E (1990) "Fluoxetine-induced bradycardia and syncope in two patients." J Clin Psychiatry, 51, p. 385-6
  5. Rodriguez de la Torre B, Dreher J, Malevany I, et al. (2001) "Serum levels and cardiovascular effects of tricyclic antidepressants and selective serotonin reuptake inhibitors in depressed patients." Ther Drug Monit, 23, p. 435-40
  6. Cerner Multum, Inc. "Australian Product Information."
  7. Pacher P, Kecskemeti V (2004) "Cardiovascular side effects of new antidepressants and antipsychotics: new drugs, old concerns?" Curr Pharm Des, 10, p. 2463-75
  8. Andrews C, Pinner G (1998) "Postural hypotension induced by paroxetine." BMJ, 316, p. 595
  9. (2023) "Product Information. Buprenorphine (buprenorphine)." G.L. Pharma UK Ltd
  10. (2023) "Product Information. Temgesic (buprenorphine)." Reckitt Benckiser Pty Ltd
Moderate

felodipine food

Applies to: felodipine

MONITOR: Calcium-containing products may decrease the effectiveness of calcium channel blockers by saturating calcium channels with calcium. Calcium chloride has been used to manage acute severe verapamil toxicity.

MANAGEMENT: Management consists of monitoring the effectiveness of calcium channel blocker therapy during coadministration with calcium products.

References (14)
  1. Henry M, Kay MM, Viccellio P (1985) "Cardiogenic shock associated with calcium-channel and beta blockers: reversal with intravenous calcium chloride." Am J Emerg Med, 3, p. 334-6
  2. Moller IW (1987) "Cardiac arrest following intravenous verapamil combined with halothane anaesthesia." Br J Anaesth, 59, p. 522-6
  3. Oszko MA, Klutman NE (1987) "Use of calcium salts during cardiopulmonary resuscitation for reversing verapamil-associated hypotension." Clin Pharm, 6, p. 448-9
  4. Schoen MD, Parker RB, Hoon TJ, et al. (1991) "Evaluation of the pharmacokinetics and electrocardiographic effects of intravenous verapamil with intravenous calcium chloride pretreatment in normal subjects." Am J Cardiol, 67, p. 300-4
  5. O'Quinn SV, Wohns DH, Clarke S, Koch G, Patterson JH, Adams KF (1990) "Influence of calcium on the hemodynamic and anti-ischemic effects of nifedipine observed during treadmill exercise testing." Pharmacotherapy, 10, p. 247
  6. Woie L, Storstein L (1981) "Successful treatment of suicidal verapamil poisoning with calcium gluconate." Eur Heart J, 2, p. 239-42
  7. Morris DL, Goldschlager N (1983) "Calcium infusion for reversal of adverse effects of intravenous verapamil." JAMA, 249, p. 3212-3
  8. Guadagnino V, Greengart A, Hollander G, Solar M, Shani J, Lichstein E (1987) "Treatment of severe left ventricular dysfunction with calcium chloride in patients receiving verapamil." J Clin Pharmacol, 27, p. 407-9
  9. Luscher TF, Noll G, Sturmer T, Huser B, Wenk M (1994) "Calcium gluconate in severe verapamil intoxication." N Engl J Med, 330, p. 718-20
  10. Bar-Or D, Gasiel Y (1981) "Calcium and calciferol antagonise effect of verapamil in atrial fibrillation." Br Med J (Clin Res Ed), 282, p. 1585-6
  11. Lipman J, Jardine I, Roos C, Dreosti L (1982) "Intravenous calcium chloride as an antidote to verapamil-induced hypotension." Intensive Care Med, 8, p. 55-7
  12. McMillan R (1988) "Management of acute severe verapamil intoxication." J Emerg Med, 6, p. 193-6
  13. Perkins CM (1978) "Serious verapamil poisoning: treatment with intravenous calcium gluconate." Br Med J, 2, p. 1127
  14. Moroni F, Mannaioni PF, Dolara A, Ciaccheri M (1980) "Calcium gluconate and hypertonic sodium chloride in a case of massive verapamil poisoning." Clin Toxicol, 17, p. 395-400

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.

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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.

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