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Drug Interactions between dextromethorphan / promethazine and Flagyl ER

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

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Interactions between your drugs

Moderate

metroNIDAZOLE promethazine

Applies to: Flagyl ER (metronidazole) and dextromethorphan / promethazine

MONITOR: QT prolongation has been reported with metronidazole, particularly when administered with drugs that have the potential for prolonging the QT interval. This may increase the risk of ventricular arrhythmias associated with QT prolongation including torsade de pointes and sudden death. According to the manufacturer, flattening of the T-wave has been observed in electrocardiographic tracings. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia). In addition, the extent of drug-induced QT prolongation is dependent on the particular drug(s) involved and dosage(s) of the drug(s).

MANAGEMENT: Caution is recommended when metronidazole is used concomitantly with agents known to cause QT prolongation. Patients should be advised to seek prompt medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitation, irregular heart rhythm, shortness of breath, or syncope.

References

  1. "Product Information. Flagyl (metronidazole)." Searle PROD (2001):
  2. Kounas SP, Letsas KP, Sideris A, Efraimidis M, Kardaras F "QT interval prolongation and torsades de pointes due to a coadministration of metronidazole and amiodarone." Pacing Clin Electrophysiol 28 (2005): 472-3
  3. Cerner Multum, Inc. "Australian Product Information." O 0
  4. "Product Information. Pylera (bismuth subcitrate potassium/metronidazo/TCN)." Aptalis Pharma (2022):
View all 4 references

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Moderate

dextromethorphan promethazine

Applies to: dextromethorphan / promethazine and dextromethorphan / promethazine

MONITOR: Central nervous system- and/or respiratory-depressant effects may be additively or synergistically increased in patients taking multiple drugs that cause these effects, especially in elderly or debilitated patients. Sedation and impairment of attention, judgment, thinking, and psychomotor skills may increase.

MANAGEMENT: During concomitant use of these drugs, patients should be monitored for potentially excessive or prolonged CNS and respiratory depression. Cautious dosage titration may be required, particularly at treatment initiation. Ambulatory patients should be counseled to avoid hazardous activities requiring mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

References

  1. Hamilton MJ, Bush M, Smith P, Peck AW "The effects of bupropion, a new antidepressant drug, and diazepam, and their interaction in man." Br J Clin Pharmacol 14 (1982): 791-7
  2. Stambaugh JE, Lane C "Analgesic efficacy and pharmacokinetic evaluation of meperidine and hydroxyzine, alone and in combination." Cancer Invest 1 (1983): 111-7
  3. Sotaniemi EA, Anttila M, Rautio A, et al. "Propranolol and sotalol metabolism after a drinking party." Clin Pharmacol Ther 29 (1981): 705-10
  4. Grabowski BS, Cady WJ, Young WW, Emery JF "Effects of acute alcohol administration on propranolol absorption." Int J Clin Pharmacol Ther Toxicol 18 (1980): 317-9
  5. Lemberger L, Rowe H, Bosomworth JC, Tenbarge JB, Bergstrom RF "The effect of fluoxetine on the pharmacokinetics and psychomotor responses of diazepam." Clin Pharmacol Ther 43 (1988): 412-9
  6. MacLeod SM, Giles HG, Patzalek G, Thiessen JJ, Sellers EM "Diazepam actions and plasma concentrations following ethanol ingestion." Eur J Clin Pharmacol 11 (1977): 345-9
  7. Divoll M, Greenblatt DJ, Lacasse Y, Shader RI "Benzodiazepine overdosage: plasma concentrations and clinical outcome." Psychopharmacology (Berl) 73 (1981): 381-3
  8. Naylor GJ, McHarg A "Profound hypothermia on combined lithium carbonate and diazepam treatment." Br Med J 2 (1977): 22
  9. Stovner J, Endresen R "Intravenous anaesthesia with diazepam." Acta Anaesthesiol Scand 24 (1965): 223-7
  10. Driessen JJ, Vree TB, Booij LH, van der Pol FM, Crul JF "Effect of some benzodiazepines on peripheral neuromuscular function in the rat in-vitro hemidiaphragm preparation." J Pharm Pharmacol 36 (1984): 244-7
  11. Feldman SA, Crawley BE "Interaction of diazepam with the muscle-relaxant drugs." Br Med J 1 (1970): 336-8
  12. Ochs HR, Greenblatt DJ, Verburg-Ochs B "Propranolol interactions with diazepam, lorazepam and alprazolam." Clin Pharmacol Ther 36 (1984): 451-5
  13. Desager JP, Hulhoven R, Harvengt C, Hermann P, Guillet P, Thiercelin JF "Possible interactions between zolpidem, a new sleep inducer and chlorpromazine, a phenothiazine neuroleptic." Psychopharmacology (Berl) 96 (1988): 63-6
  14. Tverskoy M, Fleyshman G, Ezry J, Bradley EL, Jr Kissin I "Midazolam-morphine sedative interaction in patients." Anesth Analg 68 (1989): 282-5
  15. "Product Information. Iopidine (apraclonidine ophthalmic)." Alcon Laboratories Inc PROD
  16. Greiff JMC, Rowbotham D "Pharmacokinetic drug interactions with gastrointestinal motility modifying agents." Clin Pharmacokinet 27 (1994): 447-61
  17. Greb WH, Buscher G, Dierdorf HD, Koster FE, Wolf D, Mellows G "The effect of liver enzyme inhibition by cimetidine and enzyme induction by phenobarbitone on the pharmacokinetics of paroxetine." Acta Psychiatr Scand 80 Suppl (1989): 95-8
  18. Markowitz JS, Wells BG, Carson WH "Interactions between antipsychotic and antihypertensive drugs." Ann Pharmacother 29 (1995): 603-9
  19. "Product Information. Ultram (tramadol)." McNeil Pharmaceutical PROD (2001):
  20. "Product Information. Artane (trihexyphenidyl)." Lederle Laboratories PROD (2001):
  21. "Product Information. Ultiva (remifentanil)." Mylan Institutional (formally Bioniche Pharma USA Inc) PROD (2001):
  22. "Product Information. Seroquel (quetiapine)." Astra-Zeneca Pharmaceuticals PROD (2001):
  23. "Product Information. Meridia (sibutramine)." Knoll Pharmaceutical Company PROD (2001):
  24. "Product Information. Tasmar (tolcapone)." Valeant Pharmaceuticals PROD (2001):
  25. Miller LG "Herbal medicinals: selected clinical considerations focusing on known or potential drug-herb interactions." Arch Intern Med 158 (1998): 2200-11
  26. "Product Information. Precedex (dexmedetomidine)." Abbott Pharmaceutical PROD (2001):
  27. "Product Information. Trileptal (oxcarbazepine)." Novartis Pharmaceuticals PROD (2001):
  28. Ferslew KE, Hagardorn AN, McCormick WF "A fatal interaction of methocarbamol and ethanol in an accidental poisoning." J Forensic Sci 35 (1990): 477-82
  29. Plushner SL "Valerian: valeriana officinalis." Am J Health Syst Pharm 57 (2000): 328-35
  30. "Product Information. Xatral (alfuzosin)." Sanofi-Synthelabo Canada Inc (2002):
  31. "Product Information. Lexapro (escitalopram)." Forest Pharmaceuticals (2002):
  32. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  33. Cerner Multum, Inc. "Australian Product Information." O 0
  34. "Product Information. Fycompa (perampanel)." Eisai Inc (2012):
  35. "Product Information. Belsomra (suvorexant)." Merck & Co., Inc (2014):
  36. "Product Information. Rexulti (brexpiprazole)." Otsuka American Pharmaceuticals Inc (2015):
View all 36 references

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Drug and food interactions

Major

metroNIDAZOLE food

Applies to: Flagyl ER (metronidazole)

CONTRAINDICATED: Use of alcohol or products containing alcohol during nitroimidazole therapy may result in a disulfiram-like reaction in some patients. There have been a few case reports involving metronidazole, although data overall are not convincing. The presumed mechanism is inhibition of aldehyde dehydrogenase (ALDH) by metronidazole in a manner similar to disulfiram. Following ingestion of alcohol, inhibition of ALDH results in increased concentrations of acetaldehyde, the accumulation of which can produce an unpleasant physiologic response referred to as the 'disulfiram reaction'. Symptoms include flushing, throbbing in head and neck, throbbing headache, respiratory difficulty, nausea, vomiting, sweating, thirst, chest pain, palpitation, dyspnea, hyperventilation, tachycardia, hypotension, syncope, weakness, vertigo, blurred vision, and confusion. Severe reactions may result in respiratory depression, cardiovascular collapse, arrhythmia, myocardial infarction, acute congestive heart failure, unconsciousness, convulsions, and death. However, some investigators have questioned the disulfiram-like properties of metronidazole. One study found neither elevations in blood acetaldehyde nor objective or subjective signs of a disulfiram-like reaction to ethanol in six subjects treated with metronidazole (200 mg three times a day for 5 days) compared to six subjects who received placebo.

MANAGEMENT: Because clear evidence is lacking concerning the safety of ethanol use during nitroimidazole therapy, patients should be apprised of the potential for interaction. Consumption of alcoholic beverages and products containing propylene glycol is specifically contraindicated during and for at least 3 days after completion of metronidazole and benznidazole therapy according to their product labeling.

References

  1. Giannini AJ, DeFrance DT "Metronidazole and alcohol: potential for combinative abuse." J Toxicol Clin Toxicol 20 (1983): 509-15
  2. Alexander I "Alcohol-antabuse syndrome in patients receiving metronidazole during gynaecological treatment." Br J Clin Pract 39 (1985): 292-3
  3. Harries DP, Teale KF, Sunderland G "Metronidazole and alcohol: potential problems." Scott Med J 35 (1990): 179-80
  4. "Product Information. Flagyl (metronidazole)." Searle PROD (2001):
  5. Edwards DL, Fink PC, Van Dyke PO "Disulfiram-like reaction associated with intravenous trimethoprim-sulfamethoxazole and metronidazole." Clin Pharm 5 (1986): 999-1000
  6. Williams CS, Woodcock KR "Do ethanol and metronidazole interact to produce a disulfiram-like reaction?." Ann Pharmacother 34 (2000): 255-7
  7. Visapaa JP, Tillonen JS, Kaihovaara PS, Salaspuro MP "Lack of disulfiram-like reaction with metronidazole and ethanol." Ann Pharmacother 36 (2002): 971-4
  8. Krulewitch CJ "An unexpected adverse drug effect." J Midwifery Womens Health 48 (2003): 67-8
  9. "Product Information. Benznidazole (benznidazole)." Everett Laboratories Inc (2017):
View all 9 references

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Moderate

dextromethorphan food

Applies to: dextromethorphan / promethazine

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

References

  1. Warrington SJ, Ankier SI, Turner P "Evaluation of possible interactions between ethanol and trazodone or amitriptyline." Neuropsychobiology 15 (1986): 31-7
  2. Gilman AG, eds., Nies AS, Rall TW, Taylor P "Goodman and Gilman's the Pharmacological Basis of Therapeutics." New York, NY: Pergamon Press Inc. (1990):
  3. "Product Information. Fycompa (perampanel)." Eisai Inc (2012):
  4. "Product Information. Rexulti (brexpiprazole)." Otsuka American Pharmaceuticals Inc (2015):
View all 4 references

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Moderate

promethazine food

Applies to: dextromethorphan / promethazine

GENERALLY AVOID: Concurrent use of ethanol and phenothiazines may result in additive CNS depression and psychomotor impairment. Also, ethanol may precipitate dystonic reactions in patients who are taking phenothiazines. The two drugs probably act on different sites in the brain, although the exact mechanism of the interaction is not known.

MANAGEMENT: Patients should be advised to avoid alcohol during phenothiazine therapy.

References

  1. Lutz EG "Neuroleptic-induced akathisia and dystonia triggered by alcohol." JAMA 236 (1976): 2422-3
  2. Freed E "Alcohol-triggered-neuroleptic-induced tremor, rigidity and dystonia." Med J Aust 2 (1981): 44-5

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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

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

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