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Drug Interactions between Etrafon Forte and Rimactane

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

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Interactions between your drugs

Moderate

amitriptyline perphenazine

Applies to: Etrafon Forte (amitriptyline / perphenazine) and Etrafon Forte (amitriptyline / perphenazine)

MONITOR: Coadministration of a phenothiazine with a tricyclic antidepressant (TCA) may result in elevated plasma concentrations of one or both drugs as well as additive adverse effects. Most phenothiazines and TCAs have been found to undergo metabolism by CYP450 2D6, thus competitive inhibition of the enzyme may occur when more than one of these agents are administered. Although these drugs have been used together clinically, the possibility of increased risk of serious adverse effects such as central nervous system depression, tardive dyskinesia, hypotension, and prolongation of the QT interval should be considered, as many of these agents alone can and have produced these effects. In addition, excessive anticholinergic effects may occur in combination use, which can result in paralytic ileus, hyperthermia, heat stroke, and the anticholinergic intoxication syndrome. Peripheral symptoms of anticholinergic intoxication commonly include mydriasis, blurred vision, flushed face, fever, dry skin and mucous membranes, tachycardia, urinary retention, and constipation. Central symptoms may include memory loss, disorientation, incoherence, hallucinations, psychosis, delirium, hyperactivity, twitching or jerking movements, stereotypy, and seizures.

MANAGEMENT: Concurrent use of phenothiazines and TCAs should be approached with caution, particularly in the elderly and those with underlying organic brain disease, who tend to be more sensitive to the central anticholinergic effects of these drugs and in whom toxicity symptoms may be easily overlooked. Patients should be advised to notify their physician promptly if they experience potential symptoms of anticholinergic intoxication (e.g., abdominal pain, fever, heat intolerance, blurred vision, confusion, hallucinations) or cardiovascular toxicity (e.g., dizziness, palpitations, arrhythmias, syncope). Ambulatory patients should be counseled to avoid activities requiring mental alertness until they know how these agents affect them. A dosage reduction in one or both drugs may be necessary if excessive adverse effects develop.

References

  1. Loga S, Curry S, Lader M "Interaction of chlorpromazine and nortriptyline in patients with schizophrenia." Clin Pharmacokinet 6 (1981): 454-62
  2. Stadnyk AN, Glezos JD "Drug-induced heat stroke." Can Med Assoc J 128 (1983): 957-9
  3. Bock JL, Nelson JC, Gray S, Jatlow PI "Desipramine hydroxylation: variability and effect of antipsychotic drugs." Clin Pharmacol Ther 33 (1983): 322-8
  4. Gram LF, Overo KF "Drug interaction: inhibitory effect of neuroleptics on metabolism of tricyclic antidepressants in man." Br Med J 1 (1972): 463-5
  5. El-Yousef MK, Manier DH "Tricyclic antidepressants and phenothiazines." JAMA 229 (1974): 1419
  6. Hirschowitz J, Bennett JA, Zemlan FP, Garver DL "Thioridazine effect on desipramine plasma levels." J Clin Psychopharmacol 3 (1983): 376-9
  7. Vandel S, Sandoz M, Vandel B, Bonin B, Allers G, Volmat R "Biotransformation of amitriptyline in man: interaction with phenothiazines." Neuropsychobiology 15 (1986): 15-9
  8. Zelman S, Guillan R "Heat stroke in phenothiazine-treated patients: a report of three fatalities." Am J Psychiatry 126 (1970): 1787-90
  9. Mann SC, Boger WP "Psychotropic drugs, summer heat and humidity, and hyperplexia: a danger restated." Am J Psychiatry 135 (1978): 1097-100
  10. Warnes H, Lehmann HE, Ban TA "Adynamic ileus during psychoactive medication: a report of three fatal and five severe cases." Can Med Assoc J 96 (1967): 1112-3
  11. Siris SG, Cooper TB, Rifkin AE, Brenner R, Lieberman JA "Plasma imipramine concentrations in patients receiving concomitant fluphenazine decanoate." Am J Psychiatry 139 (1982): 104-6
  12. Johnson AL, Hollister LE, Berger PA "The anticholinergic intoxication syndrome: diagnosis and treatment." J Clin Psychiatry 42 (1981): 313-7
  13. Lee BS "Possibility of hyperpyrexia with antipsychotic and anticholinergic drugs." J Clin Psychiatry 47 (1986): 571
  14. Moreau A, Jones BD, Banno V "Chronic central anticholinergic toxicity in manic depressive illness mimicking dementia." Can J Psychiatry 31 (1986): 339-41
  15. Hvizdos AJ, Bennett JA, Wells BG, Rappaport KB, Mendel SA "Anticholinergic psychosis in a patient receiving usual doses of haloperidol." Clin Pharm 2 (1983): 174-8
  16. Maynard GL, Soni P "Thioridazine interferences with imipramine metabolism and measurement." Ther Drug Monit 18 (1996): 729-31
View all 16 references

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Minor

rifAMPin amitriptyline

Applies to: Rimactane (rifampin) and Etrafon Forte (amitriptyline / perphenazine)

Rifampin may decrease the serum concentration of tricyclic antidepressants and their therapeutic effects. The proposed mechanism is metabolic induction. The clinical significance is unknown. Dosage adjustments may be required if an interaction is suspected.

References

  1. Bebchuk JM, Stewart DE "Drug interaction between rifampin and nortriptyline: a case report." Int J Psychiatry Med 21 (1991): 183-7

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Drug and food interactions

Moderate

rifAMPin food

Applies to: Rimactane (rifampin)

GENERALLY AVOID: Concurrent use of rifampin in patients who ingest alcohol daily may result in an increased incidence of hepatotoxicity. The increase in hepatotoxicity may be due to an additive risk as both alcohol and rifampin are individually associated with this adverse reaction. However, the exact mechanism has not been established.

ADJUST DOSING INTERVAL: Administration with food may reduce oral rifampin absorption, increasing the risk of therapeutic failure or resistance. In a randomized, four-period crossover phase I study of 14 healthy male and female volunteers, the pharmacokinetics of single dose rifampin 600 mg were evaluated under fasting conditions and with a high-fat meal. Researchers observed that administration of rifampin with a high-fat meal reduced rifampin peak plasma concentration (Cmax) by 36%, nearly doubled the time to reach peak plasma concentration (Tmax) but reduced overall exposure (AUC) by only 6%.

MANAGEMENT: The manufacturer of oral forms of rifampin recommends administration on an empty stomach, 30 minutes before or 2 hours after meals. Patients should be encouraged to avoid alcohol or strictly limit their intake. Patients who use alcohol and rifampin concurrently or have a history of alcohol use disorder may require additional monitoring of their liver function during treatment with rifampin.

References

  1. "Product Information. Rifampin (rifAMPin)." Akorn Inc (2022):
  2. "Product Information. Rifampicin (rifampicin)." Mylan Pharmaceuticals Inc (2022):
  3. "Product Information. Rifadin (rifampicin)." Sanofi (2023):
  4. "Product Information. Rifadin (rifaMPICin)." Sanofi-Aventis Australia Pty Ltd (2024):
  5. Peloquin CA, Namdar R, Singleton MD, Nix DE "Pharmacokinetics of rifampin under fasting conditions, with food, and with antacids https://pubmed.ncbi.nlm.nih.gov/9925057/" (2024):
  6. "Product Information. Rofact (rifampin)." Bausch Health, Canada Inc. (2019):
View all 6 references

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Moderate

amitriptyline food

Applies to: Etrafon Forte (amitriptyline / perphenazine)

GENERALLY AVOID: Concomitant use of ethanol and a tricyclic antidepressant (TCA) may result altered TCA plasma levels and efficacy, and additive impairment of motor skills, especially driving skills. Acute ethanol ingestion may inhibit TCA metabolism, while chronic ingestion of large amounts of ethanol may induce hepatic TCA metabolism.

MANAGEMENT: Patients should be advised to avoid alcohol during TCA therapy. Alcoholics who have undergone detoxification should be monitored for decreased TCA efficacy. Dosage adjustments may be required.

References

  1. Dorian P, Sellers EM, Reed KL, et al. "Amitriptyline and ethanol: pharmacokinetic and pharmacodynamic interaction." Eur J Clin Pharmacol 25 (1983): 325-31
  2. Warrington SJ, Ankier SI, Turner P "Evaluation of possible interactions between ethanol and trazodone or amitriptyline." Neuropsychobiology 15 (1986): 31-7
  3. Sandoz M, Vandel S, Vandel B, Bonin B, Allers G, Volmat R "Biotransformation of amitriptyline in alcoholic depressive patients." Eur J Clin Pharmacol 24 (1983): 615-21
  4. Ciraulo DA, Barnhill JG, Jaffe JH "Clinical pharmacokinetics of imipramine and desipramine in alcoholics and normal volunteers." Clin Pharmacol Ther 43 (1988): 509-18
  5. Seppala T, Linnoila M, Elonen E, Mattila MJ, Makl M "Effect of tricyclic antidepressants and alcohol on psychomotor skills related to driving." Clin Pharmacol Ther 17 (1975): 515-22
  6. Ciraulo DA, Barnhill JG, Jaffe JH, Ciraulo AM, Tarmey MF "Intravenous pharmacokinetics of 2-hydroxyimipramine in alcoholics and normal controls." J Stud Alcohol 51 (1990): 366-72
  7. Ciraulo DA, Alderson LM, Chapron DJ, Jaffe JH, Subbarao B, Kramer PA "Imipramine disposition in alcoholics." J Clin Psychopharmacol 2 (1982): 2-7
View all 7 references

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Moderate

perphenazine food

Applies to: Etrafon Forte (amitriptyline / perphenazine)

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

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