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Drug Interactions between Mepergan Fortis and metronidazole

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

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Interactions between your drugs

Moderate

meperidine promethazine

Applies to: Mepergan Fortis (meperidine / promethazine) and Mepergan Fortis (meperidine / promethazine)

ADJUST DOSE: The central nervous system and respiratory depressant effects of meperidine may be potentiated by concomitant use of other agents with CNS depressant effects. An increased risk of serious adverse reactions such as respiratory depression, hypotension, profound sedation, syncope, coma, and even death should be considered, particularly in elderly or debilitated patients.

MANAGEMENT: Caution and dosage adjustments are advisable when meperidine is used in combination with other narcotic analgesics, general anesthetics, phenothiazines, sedative-hypnotics, tranquilizers, tricyclic antidepressants, or other CNS depressants such as alcohol. A lower dosage of meperidine should be considered initially, then titrated carefully according to pain level and clinical response. Meperidine dosage reductions of 25% to 50% have been recommended for patients receiving phenothiazines and other tranquilizers. Patients should be advised to avoid rising abruptly from a sitting or recumbent position, and to notify their physician if they experience dizziness, lightheadedness, orthostasis, syncope, tachycardia, or excessive CNS effects that interfere with their normal activities. Patients should also avoid driving or operating hazardous machinery until they know how these medications affect them.

References (5)
  1. Lambertsen CJ, Wendel H, Longenhagen JB (1961) "The separate and combined respiratory effects of chlorpromazine and meperidine in normal men controlled at 46 mm Hg alveolar pCO2." J Pharmacol Exp Ther, 131, p. 381-93
  2. Hoffman JC, Smith TC (1970) "The respiratory effects of meperidine and propiomazine in man." Anesthesiology, 32, p. 325-31
  3. Stambaugh JE, Wainer IW (1981) "Drug interaction: meperidine and chlorpromazine, a toxic combination." J Clin Pharmacol, 21, p. 140-6
  4. (2002) "Product Information. Demerol (meperidine)." Sanofi Winthrop Pharmaceuticals
  5. (2022) "Product Information. Meperidine Hydrochloride (meperidine)." Astra-Zeneca Pharmaceuticals
Moderate

metroNIDAZOLE promethazine

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

Drug and food/lifestyle interactions

Major

metroNIDAZOLE food/lifestyle

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

meperidine food/lifestyle

Applies to: Mepergan Fortis (meperidine / promethazine)

GENERALLY AVOID: Ethanol may potentiate the central nervous system (CNS) depressant effects of opioid analgesics. Concomitant use may result in additive CNS depression and impairment of judgment, thinking, and psychomotor skills. In more severe cases, hypotension, respiratory depression, profound sedation, coma, or even death may occur.

MANAGEMENT: Concomitant use of opioid analgesics with ethanol should be avoided.

References (9)
  1. Linnoila M, Hakkinen S (1974) "Effects of diazepam and codeine, alone and in combination with alcohol, on simulated driving." Clin Pharmacol Ther, 15, p. 368-73
  2. Sturner WQ, Garriott JC (1973) "Deaths involving propoxyphene: a study of 41 cases over a two-year period." JAMA, 223, p. 1125-30
  3. Girre C, Hirschhorn M, Bertaux L, et al. (1991) "Enhancement of propoxyphene bioavailability by ethanol: relation to psychomotor and cognitive function in healthy volunteers." Eur J Clin Pharmacol, 41, p. 147-52
  4. Levine B, Saady J, Fierro M, Valentour J (1984) "A hydromorphone and ethanol fatality." J Forensic Sci, 29, p. 655-9
  5. Sellers EM, Hamilton CA, Kaplan HL, Degani NC, Foltz RL (1985) "Pharmacokinetic interaction of propoxyphene with ethanol." Br J Clin Pharmacol, 19, p. 398-401
  6. Carson DJ (1977) "Fatal dextropropoxyphene poisoning in Northern Ireland. Review of 30 cases." Lancet, 1, p. 894-7
  7. Rosser WW (1980) "The interaction of propoxyphene with other drugs." Can Med Assoc J, 122, p. 149-50
  8. Edwards C, Gard PR, Handley SL, Hunter M, Whittington RM (1982) "Distalgesic and ethanol-impaired function." Lancet, 2, p. 384
  9. Kiplinger GF, Sokol G, Rodda BE (1974) "Effect of combined alcohol and propoxyphene on human performance." Arch Int Pharmacodyn Ther, 212, p. 175-80
Moderate

promethazine food/lifestyle

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

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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