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Drug Interaction Report

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

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Interactions between your drugs

Moderate

acetaminophen interferon beta-1a

Applies to: Theraflu ExpressMax Flu, Cough & Sore Throat (acetaminophen / diphenhydramine / phenylephrine), Rebif (interferon beta-1a)

MONITOR: Coadministration of beta interferons with other agents known to induce hepatotoxicity may potentiate the risk of liver injury. Use of beta interferons has been associated with rare cases of liver injury, including autoimmune hepatitis and severe liver damage leading to hepatic failure, some of which required transplantation. In some cases, these events have occurred in the presence of other drugs that have been associated with hepatic injury. Symptoms of liver dysfunction typically began from 1 to 6 months following the initiation of therapy. Asymptomatic elevation of hepatic transaminases (particularly SGPT) have also been reported but is common with interferon therapy.

MANAGEMENT: The risk of hepatic injury should be considered when beta interferons are used with other potentially hepatotoxic agents (e.g., acetaminophen; alcohol; androgens and anabolic steroids; antituberculous agents; azole antifungal agents; ACE inhibitors; cyclosporine (high dosages); disulfiram; endothelin receptor antagonists; other interferons; ketolide and macrolide antibiotics; kinase inhibitors; minocycline; nonsteroidal anti-inflammatory agents; nucleoside reverse transcriptase inhibitors; proteasome inhibitors; retinoids; sulfonamides; tamoxifen; thiazolidinediones; tolvaptan; vincristine; zileuton; anticonvulsants such as carbamazepine, hydantoins, felbamate, and valproic acid; lipid-lowering medications such as fenofibrate, lomitapide, mipomersen, niacin, and statins; herbals and nutritional supplements such as black cohosh, chaparral, comfrey, DHEA, kava, pennyroyal oil, and red yeast rice). Liver function tests should be monitored at regular intervals and the interferon dosage reduced if SGPT rises above 5 times the upper limit of normal. The dosage may be gradually re-escalated when enzyme levels return to normal. Patients should be advised to seek medical attention if they experience potential signs and symptoms of hepatotoxicity such as fever, rash, itching, anorexia, nausea, vomiting, fatigue, malaise, right upper quadrant pain, dark urine, pale stools, and jaundice. If liver injury is suspected, interferon therapy should be promptly discontinued due to the potential for rapid progression to liver failure.

References

  1. (2002) "Product Information. Betaseron (interferon beta-1b)." Berlex Laboratories
  2. (2001) "Product Information. Avonex (interferon beta-1a)." Biogen
  3. (2002) "Product Information. Rebif (interferon beta-1a)." Serono Laboratories Inc
  4. (2014) "Product Information. Plegridy (peginterferon beta-1a)." Biogen Idec Inc
View all 4 references

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Drug and food interactions

Major

acetaminophen food

Applies to: Theraflu ExpressMax Flu, Cough & Sore Throat (acetaminophen / diphenhydramine / phenylephrine)

GENERALLY AVOID: Chronic, excessive consumption of alcohol may increase the risk of acetaminophen-induced hepatotoxicity, which has included rare cases of fatal hepatitis and frank hepatic failure requiring liver transplantation. The proposed mechanism is induction of hepatic microsomal enzymes during chronic alcohol use, which may result in accelerated metabolism of acetaminophen and increased production of potentially hepatotoxic metabolites.

MANAGEMENT: In general, chronic alcoholics should avoid regular or excessive use of acetaminophen. Alternative analgesic/antipyretic therapy may be appropriate in patients who consume three or more alcoholic drinks per day. However, if acetaminophen is used, these patients should be cautioned not to exceed the recommended dosage (maximum 4 g/day in adults and children 12 years of age or older).

References

  1. Kaysen GA, Pond SM, Roper MH, Menke DJ, Marrama MA (1985) "Combined hepatic and renal injury in alcoholics during therapeutic use of acetaminophen." Arch Intern Med, 145, p. 2019-23
  2. O'Dell JR, Zetterman RK, Burnett DA (1986) "Centrilobular hepatic fibrosis following acetaminophen-induced hepatic necrosis in an alcoholic." JAMA, 255, p. 2636-7
  3. Seeff LB, Cuccherini BA, Zimmerman HJ, Adler E, Benjamin SB (1986) "Acetaminophen hepatotoxicity in alcoholics." Ann Intern Med, 104, p. 399-404
  4. Thummel KE, Slattery JT, Nelson SD (1988) "Mechanism by which ethanol diminishes the hepatotoxicity of acetaminophen." J Pharmacol Exp Ther, 245, p. 129-36
  5. McClain CJ, Kromhout JP, Peterson FJ, Holtzman JL (1980) "Potentiation of acetaminophen hepatotoxicity by alcohol." JAMA, 244, p. 251-3
  6. Kartsonis A, Reddy KR, Schiff ER (1986) "Alcohol, acetaminophen, and hepatic necrosis." Ann Intern Med, 105, p. 138-9
  7. Prescott LF, Critchley JA (1983) "Drug interactions affecting analgesic toxicity." Am J Med, 75, p. 113-6
  8. (2002) "Product Information. Tylenol (acetaminophen)." McNeil Pharmaceutical
  9. Whitcomb DC, Block GD (1994) "Association of acetaminopphen hepatotoxicity with fasting and ethanol use." JAMA, 272, p. 1845-50
  10. Bonkovsky HL (1995) "Acetaminophen hepatotoxicity, fasting, and ethanol." JAMA, 274, p. 301
  11. Nelson EB, Temple AR (1995) "Acetaminophen hepatotoxicity, fasting, and ethanol." JAMA, 274, p. 301
  12. Zimmerman HJ, Maddrey WC (1995) "Acetaminophen (paracetamol) hepatotoxicity with regular intake of alcohol: analysis of instances of therapeutic misadventure." Hepatology, 22, p. 767-73
View all 12 references

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Moderate

diphenhydrAMINE food

Applies to: Theraflu ExpressMax Flu, Cough & Sore Throat (acetaminophen / diphenhydramine / phenylephrine)

GENERALLY AVOID: Use of anticholinergic agents with alcohol may result in sufficient impairment of attention so as to render driving and operating machinery more hazardous. In addition, the potential for abuse may be increased with the combination. The mechanism of interaction is not established but may involve additive depressant effects on the central nervous system. No effect of oral propantheline or atropine on blood alcohol levels was observed in healthy volunteers when administered before ingestion of a standard ethanol load. However, one study found impairment of attention in subjects given atropine 0.5 mg or glycopyrrolate 1 mg in combination with alcohol.

MANAGEMENT: Alcohol should generally be avoided during therapy with anticholinergic agents. Patients should be counseled to avoid activities requiring mental alertness until they know how these agents affect them.

References

  1. Linnoila M (1973) "Drug effects on psychomotor skills related to driving: interaction of atropine, glycopyrrhonium and alcohol." Eur J Clin Pharmacol, 6, p. 107-12

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Moderate

phenylephrine food

Applies to: Theraflu ExpressMax Flu, Cough & Sore Throat (acetaminophen / diphenhydramine / phenylephrine)

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.