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Drug Interaction Report

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

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Interactions between your drugs

Major

lidocaine iohexol

Applies to: Xylocaine with Epinephrine Dental Cartridges (epinephrine / lidocaine), Omnipaque 140 (iohexol)

GENERALLY AVOID: Intrathecal administration of iodinated contrast media may induce seizures. Although clinical data are generally lacking, there may be a theoretical risk of increased seizure potential when used with selective serotonin reuptake inhibitors (SSRI antidepressants or anorectics), monoamine oxidase inhibitors, neuroleptic agents, central nervous system stimulants, opioids, tricyclic antidepressants, other tricyclic compounds (e.g., cyclobenzaprine, phenothiazines), and/or any substance that can reduce the seizure threshold (e.g., carbapenems, cholinergic agents, fluoroquinolones, interferons, chloroquine, mefloquine, lindane, theophylline). These agents are often individually epileptogenic and may have additive effects when combined.

MANAGEMENT: Drugs that can lower the seizure threshold should preferably be withheld for at least 48 hours prior to and 24 hours following intrathecal administration of iodinated contrast media, provided that temporary interruption of therapy does not pose an undue risk to the patient. Otherwise, close monitoring is advised during and after contrast administration. The manufacturers typically recommend avoiding concomitant administration of phenothiazines (including those used for their antihistamine properties), monoamine oxidase inhibitors, tricyclic antidepressants, central nervous system stimulants, and psychoactive drugs.

References

  1. Hindmarsh T, Grepe A, Widen L (1975) "Metrizamide-phenothiazine interaction: report of a case with seizures following myelography." Acta Radiol Diagn (Stockh), 16, p. 129-35
  2. (2001) "Product Information. Amipaque (metrizamide)." Nycomed Inc
  3. (2001) "Product Information. Osmovist 240 (iotrolan)." Berlex Canada Inc
  4. (2007) "Product Information. Omnipaque 180 (iohexol)." Amersham Health
  5. (2007) "Product Information. Isovue-M-200 (iopamidol)." Bracco Diagnostics Inc
View all 5 references

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Drug and food interactions

Moderate

lidocaine food

Applies to: Xylocaine with Epinephrine Dental Cartridges (epinephrine / lidocaine)

MONITOR: Grapefruit and grapefruit juice may increase the plasma concentrations of lidocaine, which is primarily metabolized by the CYP450 3A4 and 1A2 isoenzymes to active metabolites (monoethylglycinexylidide (MEGX) and glycinexylidide). The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. Inhibition of hepatic CYP450 3A4 may also contribute. The interaction has not been studied with grapefruit juice but has been reported with oral and/or intravenous lidocaine and potent CYP450 3A4 inhibitor, itraconazole, as well as moderate CYP450 3A4 inhibitor, erythromycin. A pharmacokinetic study of 9 healthy volunteers showed that the administration of lidocaine oral (1 mg/kg single dose) with itraconazole (200 mg daily) increased lidocaine systemic exposure (AUC) and peak plasma concentration (Cmax) by 75% and 55%, respectively. However, no changes were observed in the pharmacokinetics of the active metabolite MEGX. In the same study, when the moderate CYP450 3A4 inhibitor erythromycin (500 mg three times a day) was administered, lidocaine AUC and Cmax increased by 60% and 40%, respectively. By contrast, when intravenous lidocaine (1.5 mg/kg infusion over 60 minutes) was administered on the fourth day of treatment with itraconazole (200 mg once a day) no changes in lidocaine AUC or Cmax were observed. However, when lidocaine (1.5 mg/kg infusion over 60 minutes) was coadministered with erythromycin (500 mg three times a day) in the same study, the AUC and Cmax of the active metabolite MEGX significantly increased by 45-60% and 40%, respectively. The observed differences between oral and intravenous lidocaine when coadministered with CYP450 3A4 inhibitors may be attributed to inhibition of CYP450 3A4 in both the gastrointestinal tract and liver affecting oral lidocaine to a greater extent than intravenous lidocaine. In general, the effects of grapefruit products are concentration-, dose- and preparation-dependent, and can vary widely among brands. Certain preparations of grapefruit (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition. While the clinical significance of this interaction is unknown, increased exposure to lidocaine may lead to serious and/or life-threatening reactions including respiratory depression, convulsions, bradycardia, hypotension, arrhythmias, and cardiovascular collapse.

MONITOR: Certain foods and behaviors that induce CYP450 1A2 may reduce the plasma concentrations of lidocaine. The proposed mechanism is induction of hepatic CYP450 1A2, one of the isoenzymes responsible for the metabolic clearance of lidocaine. Cigarette smoking is known to be a CYP450 1A2 inducer. In one pharmacokinetic study of 4 smokers and 5 non-smokers who received 2 doses of lidocaine (100 mg IV followed by 100 mg orally after a 2-day washout period), the smokers' systemic exposure (AUC) of oral lidocaine was 68% lower than non-smokers. The AUC of IV lidocaine was only 9% lower in smokers compared with non-smokers. Other CYP450 1A2 inducers include cruciferous vegetables (e.g., broccoli, brussels sprouts) and char-grilled meat. Therefore, eating large or variable amounts of these foods could also reduce lidocaine exposure. The clinical impact of smoking and/or the ingestion of foods that induce CYP450 1A2 on lidocaine have not been studied, however, a loss of efficacy may occur.

MANAGEMENT: Caution is recommended if lidocaine is to be used in combination with grapefruit and grapefruit juice. Monitoring for lidocaine toxicity and plasma lidocaine levels may also be advised, and the lidocaine dosage adjusted as necessary. Patients who smoke and/or consume cruciferous vegetables may be monitored for reduced lidocaine efficacy.

References

  1. Huet PM, LeLorier J (1980) "Effects of smoking and chronic hepatitis B on lidocaine and indocyanine green kinetics" Clin Pharmacol Ther, 28, p. 208-15
  2. (2024) "Product Information. Lidocaine Hydrochloride (lidocaine)." Hospira Inc.
  3. (2015) "Product Information. Lidocaine Hydrochloride (lidocaine)." Hospira Healthcare Corporation
  4. (2022) "Product Information. Lidocaine Hydrochloride (lidocaine)." Hameln Pharma Ltd
  5. (2022) "Product Information. Xylocaine HCl (lidocaine)." Aspen Pharmacare Australia Pty Ltd
  6. Isohanni MH, Neuvonen PJ, Olkkola KT (2024) Effect of erythromycin and itraconazole on the pharmacokinetics of oral lignocaine https://pubmed.ncbi.nlm.nih.gov/10193676/
  7. Isohanni MH, Neuvonen PJ, Olkkola KT (2024) Effect of erythromycin and itraconazole on the pharmacokinetics of intravenous lignocaine https://pubmed.ncbi.nlm.nih.gov/9832299/
View all 7 references

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Moderate

EPINEPHrine food

Applies to: Xylocaine with Epinephrine Dental Cartridges (epinephrine / lidocaine)

MONITOR: Coadministration of two or more sympathomimetic agents may increase the risk of adverse effects such as nervousness, irritability, and increased heart rate. Central nervous system (CNS) stimulants, particularly amphetamines, can potentiate the adrenergic response to vasopressors and other sympathomimetic agents. Additive increases in blood pressure and heart rate may occur due to enhanced peripheral sympathetic activity.

MANAGEMENT: Caution is advised if two or more sympathomimetic agents are coadministered. Pulse and blood pressure should be closely monitored.

References

  1. Rosenblatt JE, Lake CR, van Kammen DP, Ziegler MG, Bunney WE Jr (1979) "Interactions of amphetamine, pimozide, and lithium on plasma norepineophrine and dopamine-beta-hydroxylase in schizophrenic patients." Psychiatry Res, 1, p. 45-52
  2. Cavanaugh JH, Griffith JD, Oates JA (1970) "Effect of amphetamine on the pressor response to tyramine: formation of p-hydroxynorephedrine from amphetamine in man." Clin Pharmacol Ther, 11, p. 656
  3. (2001) "Product Information. Adderall (amphetamine-dextroamphetamine)." Shire Richwood Pharmaceutical Company Inc
  4. (2001) "Product Information. Tenuate (diethylpropion)." Aventis Pharmaceuticals
  5. (2001) "Product Information. Sanorex (mazindol)." Novartis Pharmaceuticals
  6. (2001) "Product Information. Focalin (dexmethylphenidate)." Mikart Inc
  7. (2002) "Product Information. Strattera (atomoxetine)." Lilly, Eli and Company
View all 7 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.