Skip to main content

Drug Interactions between Cerebyx and Metro

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

Edit list (add/remove drugs)

Interactions between your drugs

Moderate

metroNIDAZOLE fosphenytoin

Applies to: Metro (metronidazole) and Cerebyx (fosphenytoin)

MONITOR: Coadministration with a nitroimidazole may increase the serum concentrations of phenytoin. The interaction has been reported with metronidazole, and the proposed mechanism is inhibition of phenytoin metabolism via CYP450 2C9. In one study, metronidazole (250 mg orally three times a day for 4 days) increased the half life of phenytoin (300 mg single intravenous dose) in healthy volunteers by 44% and reduced its clearance by 15% compared to control values. However, another study found no effect of metronidazole (400 mg orally twice a day) on the pharmacokinetics of orally administered phenytoin (300 mg single dose). No data are available for tinidazole.

MANAGEMENT: Pharmacologic response and serum phenytoin levels should be monitored more closely whenever metronidazole is added to or withdrawn from therapy, and the phenytoin (or fosphenytoin) dosage adjusted as necessary. Patients should be advised to notify their physician if they experience potential symptoms of phenytoin toxicity such as nausea, vomiting, nystagmus, slurred speech, lethargy, tremor, ataxia, hyperreflexia, and dysarthria. Given its structural similarities to metronidazole, the same precaution may be applicable during therapy with tinidazole, although clinical data are lacking.

References

  1. Jensen JC, Gugler R (1985) "Interaction between metronidazole and drugs eliminated by oxidative metabolism." Clin Pharmacol Ther, 37, p. 407-10
  2. Blyden GT, Scavone JM, Greenblatt DJ (1988) "Metronidazole impairs clearance of phenytoin but not of alprazolam or lorazepam." J Clin Pharmacol, 28, p. 240-5
  3. (2001) "Product Information. Flagyl (metronidazole)." Searle
  4. (2004) "Product Information. Tindamax (tinidazole)." Presutti Laboratories Inc
View all 4 references

Switch to consumer interaction data

Drug and food interactions

Major

metroNIDAZOLE food

Applies to: Metro (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 (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
View all 9 references

Switch to consumer interaction data

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.


Report options

Loading...
QR code containing a link to this page

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.