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Drug Interactions between Dilt-XR and quetiapine

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

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Interactions between your drugs

Moderate

dilTIAZem QUEtiapine

Applies to: Dilt-XR (diltiazem) and quetiapine

MONITOR: Coadministration with inhibitors of CYP450 3A4 may increase the plasma concentrations of quetiapine, which is primarily metabolized by the isoenzyme. In 12 healthy volunteers, administration of a single 25 mg dose of quetiapine with the potent CYP450 3A4 inhibitor ketoconazole (200 mg once daily for 4 days) increased mean quetiapine peak plasma concentration (Cmax) and systemic exposure (AUC) by 3.4- and 6.2-fold, respectively, and decreased mean oral clearance by 84% compared to quetiapine administered alone. A case report describes a patient treated with quetiapine 700 mg/day who developed severely impaired consciousness and respiratory depression requiring intensive care surveillance following two 500 mg doses of clarithromycin, another potent CYP450 3A4 inhibitor. Quetiapine plasma level was found to be nearly 5 times the high end of the recommended therapeutic range. The patient recovered a week after quetiapine was withdrawn. The interaction was also suspected in a case report of two patients receiving quetiapine with ritonavir-boosted atazanavir. One patient experienced significant increases in appetite and serum glucose and a weight gain of more than 22 kg over six months. The patient's weight returned to baseline five months after stopping both treatments. The second patient had increased sedation and mental confusion, which resolved several days following self-discontinuation of quetiapine.

MANAGEMENT: Pharmacologic response to quetiapine should be monitored more closely whenever a CYP450 3A4 inhibitor is added to or withdrawn from therapy, and the quetiapine dosage adjusted as necessary. Patients should be monitored for potentially increased adverse effects such as dizziness, drowsiness, dry mouth, constipation, increased appetite, weight gain, extrapyramidal symptoms, tardive dyskinesia, hyperglycemia, dyslipidemia, hyperprolactinemia (galactorrhea, amenorrhea, gynecomastia), orthostatic hypotension, blood pressure increases (in children and adolescents), QT prolongation, cognitive and motor impairment, dysphagia, and heat-related illnesses due to disruption of body temperature regulation.

References

  1. (2001) "Product Information. Seroquel (quetiapine)." Astra-Zeneca Pharmaceuticals
  2. (1997) "Quetiapine for schizophrenia." Med Lett Drugs Ther, 39, p. 117-8
  3. DeVane CL, Nemeroff CB (2001) "Clinical pharmacokinetics of quetiapine - An atypical antipsychotic." Clin Pharmacokinet, 40, p. 509-22
  4. Spina E, Scordo MG, D'Arrigo C (2003) "Metabolic drug interactions with new psychotropic agents." Fundam Clin Pharmacol, 17, p. 517-38
  5. Grimm SW, Richtand NM, Winter HR, Stams KR, Reele SB (2006) "Effects of cytochrome P450 3A modulators ketoconazole and carbamazepine on quetiapine pharmacokinetics." Br J Clin Pharmacol, 61, p. 58-69
  6. Spina E, de Leon J (2007) "Metabolic drug interactions with newer antipsychotics: a comparative review." Basic Clin Pharmacol Toxicol, 100, p. 4-22
  7. Urichuk L, Prior TI, Dursun S, Baker G (2008) "Metabolism of atypical antipsychotics: involvement of cytochrome p450 enzymes and relevance for drug-drug interactions." Curr Drug Metab, 9, p. 410-8
  8. Schulz-Du Bois C, Schulz-Du Bois AC, Bewig B, et al. (2008) "Major increase of quetiapine steady-state plasma concentration following co-administration of clarithromycin: confirmation of the pharmacokinetic interaction potential of quetiapine." Pharmacopsychiatry, 41, p. 258-9
  9. Hantson P, Di Fazio V, Wallemacq P (2010) "Toxicokinetic interaction between quetiapine and antiretroviral therapy following quetiapine overdose." Drug Metab Lett, 4, p. 7-8
View all 9 references

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Drug and food interactions

Moderate

dilTIAZem food

Applies to: Dilt-XR (diltiazem)

MONITOR: Like many CNS-active agents, alcohol can exhibit hypotensive effects. Coadministration with antihypertensive agents including diltiazem may result in additive effects on blood pressure and orthostasis.

MONITOR: Grapefruit juice may increase the plasma concentrations of orally administered diltiazem in some patients. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. In a study of ten healthy male volunteers, administration of a single 120 mg oral dose of immediate-release diltiazem in combination with 250 mL of grapefruit juice increased the diltiazem peak plasma concentration (Cmax) and systemic exposure (AUC) by an average of 22% and 20%, respectively, compared to administration with water. The time to reach Cmax (Tmax) and the terminal half-life were not affected, and no statistically significant differences in blood pressure and heart rate were observed during administration with grapefruit juice relative to water. In a different study, repeated administration of 200 mL of grapefruit juice at 0, 2, 4, 8 and 12 hours had no significant effect on the Cmax or AUC of a single 120 mg oral dose of diltiazem, but increased its half-life from 4.1 to 5.1 hours. The ratios for the N-demethyl and deacetyl metabolites to diltiazem were also not affected by grapefruit juice. However, because pharmacokinetic interactions involving grapefruit juice are often subject to a high degree of interpatient variability, the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: Patients should be advised that alcohol may potentiate the hypotensive effects of diltiazem, especially during the initiation of therapy and following a dosage increase. Caution should be exercised when rising from a sitting or recumbent position, and patients should notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia. Patients who regularly consume grapefruit or grapefruit juice should be monitored for increased adverse effects of diltiazem such as such as headache, irregular heartbeat, edema, unexplained weight gain, and chest pain. Grapefruit and grapefruit juice should be avoided if an interaction is suspected.

References

  1. Bailey DG, Arnold JMO, Spence JD (1994) "Grapefruit juice and drugs - how significant is the interaction." Clin Pharmacokinet, 26, p. 91-8
  2. Sigusch H, Henschel L, Kraul H, Merkel U, Hoffmann A (1994) "Lack of effect of grapefruit juice on diltiazem bioavailability in normal subjects." Pharmazie, 49, p. 675-9
  3. Bailey DG, Malcolm J, Arnold O, Spence JD (1998) "Grapefruit juice-drug interactions." Br J Clin Pharmacol, 46, p. 101-10
  4. Christensen H, Asberg A, Holmboe AB, Berg KJ (2002) "Coadministration of grapefruit juice increases systemic exposure of diltiazem in healthy volunteers." Eur J Clin Pharmacol, 58, p. 515-520
  5. Cerner Multum, Inc. "UK Summary of Product Characteristics."
View all 5 references

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Moderate

dilTIAZem food

Applies to: Dilt-XR (diltiazem)

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

  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
View all 14 references

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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.

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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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