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Drug Interaction Report

2 potential interactions and/or warnings found for the following 2 drugs:

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Interactions between your drugs

Major

quiNINE sparfloxacin

Applies to: quinine, Zagam (sparfloxacin)

CONTRAINDICATED: Sparfloxacin may cause dose-related prolongation of the QT interval in some patients. Theoretically, coadministration with other agents that can prolong the QT interval may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death. Torsade de pointes has been reported in a few patients receiving sparfloxacin alone and with antiarrhythmic agents like amiodarone and disopyramide.

MANAGEMENT: Coadministration of sparfloxacin with other drugs that can prolong the QT interval is considered contraindicated.

References

  1. Thomas M, Maconochie JG, Fletcher E (1996) "The dilemma of the prolonged QT interval in early drug studies." Br J Clin Pharmacol, 41, p. 77-81
  2. Jaillon P, Morganroth J, Brumpt I, Talbot G (1996) "Overview of electrocardiographic and cardiovascular safety data for sparfloxacin. Sparfloxacin Safety Group." J Antimicrob Chemother, 37(suppl a), p. 161-7
  3. Zix JA, GeerdesFenge HF, Rau M, Vockler J, Borner K, Koeppe P, Lode H (1997) "Pharmacokinetics of sparfloxacin and interaction with cisapride and sucralfate." Antimicrob Agents Chemother, 41, p. 1668-72
  4. (2001) "Product Information. Zagam (sparfloxacin)." Rhone Poulenc Rorer
  5. Demolis JL, Charransol A, Funck-Brentano C, Jaillon P (1996) "Effects of a single oral dose of sparfloxacin on ventricular repolarization in healthy volunteers." Br J Clin Pharmacol, 41, p. 499-503
  6. Dupont H, Timsit JF, Souweine B, Gachot B, Wolff M, Regnier B (1996) "Torsades de pointe probably related to sparfloxacin." Eur J Clin Microbiol Infect Dis, 15, p. 350-1
  7. Lipsky BA, Dorr MB, Magner DJ, Talbot GH (1999) "Safety profile of sparfloxacin, a new fluoroquinolone antibiotic." Clin Ther, 21, p. 148-59
  8. Owens RC (2001) "Risk assessment for antimicrobial agent-induced QTc interval prolongation and torsades de pointes." Pharmacotherapy, 21, p. 301-19
  9. Iannini PB, Doddamani S, Byazrova E, Curciumaru I, Kramer H (2001) "Risk of torsades de pointes with non-cardiac drugs." BMJ, 322, p. 46-7
  10. Ball P (2000) "Quinolone-induced QT interval prolongation: a not-so-unexpected class effect." J Antimicrob Chemother, 45, p. 557-9
  11. Kang J, Wang L, Chen XL, Triggle DJ, Rampe D (2001) "Interactions of a series of fluoroquinolone antibacterial drugs with the human cardiac K+ channel HERG." Mol Pharmacol, 59, p. 122-6
  12. Oliphant CM, Green GM (2002) "Quinolones: a comprehensive review." Am Fam Physician, 65, p. 455-64
  13. Owens RC Jr, Ambrose PG (2002) "Torsades de pointes associated with fluoroquinolones." Pharmacotherapy, 22, 663-8; discussion 668-72
  14. Iannini PB (2002) "Cardiotoxicity of macrolides, ketolides and fluoroquinolones that prolong the QTc interval." Expert Opin Drug Saf, 1, p. 121-8
  15. Owens RC (2004) "QT Prolongation with Antimicrobial Agents : Understanding the Significance." Drugs, 64, p. 1091-124
  16. Katritsis D, Camm AJ (2003) "Quinolones: cardioprotective or cardiotoxic." Pacing Clin Electrophysiol, 26, p. 2317-20
  17. Stahlmann R (2002) "Clinical toxicological aspects of fluoroquinolones." Toxicol Lett, 127, p. 269-77
  18. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  19. Canadian Pharmacists Association (2006) e-CPS. http://www.pharmacists.ca/function/Subscriptions/ecps.cfm?link=eCPS_quikLink
  20. Falagas ME, Rafailidis PI, Rosmarakis ES (2007) "Arrhythmias associated with fluoroquinolone therapy." Int J Antimicrob Agents, 29, p. 374-9
  21. Cerner Multum, Inc. "Australian Product Information."
View all 21 references

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Drug and food interactions

Minor

quiNINE food

Applies to: quinine

Coadministration with grapefruit juice does not appear to affect the pharmacokinetics of quinine in a clinically relevant manner. Although grapefruit juice is an inhibitor of CYP450 3A4 and quinine is metabolized by this pathway to its major metabolite, 3-hydroxyquinine, a study of ten healthy volunteers found no significant differences in quinine peak plasma concentration (Cmax), time to reach Cmax (Tmax), terminal elimination half-life, systemic exposure (AUC), or apparent oral clearance (Cl/F) when a single 600 mg oral dose of quinine sulfate was administered in combination with 200 mL of orange juice (control), half-strength grapefruit juice, and full-strength grapefruit juice twice daily for 6 days each, separated by a 2-week washout period. Relative to the control period, the apparent renal clearance of quinine was markedly increased by 81% during treatment with half-strength grapefruit juice. However, since renal clearance accounts for approximately 6% of the total clearance of quinine, this change would likely have minimal clinical impact. The lack of a significant interaction is probably due to the fact that grapefruit juice primarily inhibits intestinal rather than hepatic CYP450 3A4, and quinine is not known to undergo significant presystemic metabolism as evidenced by its relatively high oral bioavailability (76% to 88%). Nevertheless, excessive consumption of grapefruit juice and tonic water (which contains quinine) was suspected as the cause of torsade de pointes arrhythmia in a patient with a history of asymptomatic long QT syndrome. Treatment with magnesium sulfate and metoprolol had no effect, but the arrhythmia resolved spontaneously 48 hours after discontinuation of the drinks. Based on current data, moderate grapefruit juice consumption is probably safe for the majority of patients taking quinine.

References

  1. Ho PC, Chalcroft SC, Coville PF, Wanwimolruk S (1999) "Grapefruit juice has no effect on quinine pharmacokinetics." Eur J Clin Pharmacol, 55, p. 393-8
  2. Hermans K, Stockman D, Van den Branden F (2003) "Grapefruit and tonic: a deadly combination in a patient with the long QT syndrome." Am J Med, 114, p. 511-2
  3. (2006) "Product Information. Qualaquin (quinine)." AR Scientific Inc
  4. Zhang H, Coville PF, Walker RJ, Miners JO, Birkett DJ, Wanwimolruk S (1997) "Evidence for involvement of human CYP3A in the 3-hydroxylation of quinine." Br J Clin Pharmacol, 43, p. 245-52
  5. Mirghani RA, Yasar U, Zheng T, et al. (2002) "Enzyme kinetics for the formation of 3-hydroxyquinine and three new metabolites of quinine in vitro; 3-hydroxylation by CYP3A4 is indeed the major metabolic pathway." Drug Metab Dispos, 30, p. 1368-71
View all 5 references

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Therapeutic duplication warnings

No duplication 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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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.