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Drug Interaction Report

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

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Interactions between your drugs

Moderate

acetaminophen butalbital

Applies to: Allzital (acetaminophen / butalbital), Allzital (acetaminophen / butalbital)

MONITOR: Barbiturates may increase the hepatotoxic potential of acetaminophen and decrease its therapeutic effects. The mechanism may be related to accelerated CYP450 metabolism of acetaminophen with consequent increase in hepatotoxic metabolites. This interaction is of greatest concern in cases of acetaminophen overdose.

MANAGEMENT: Monitoring for altered efficacy and safety is recommended. Prolonged use or high doses of acetaminophen should be avoided by patients on barbiturate therapy.

References

  1. Pirotte JH (1984) "Apparent potentiation by phenobarbital of hepatotoxicity from small doses of acetaminophen." Ann Intern Med, 101, p. 403
  2. Douidar SM, Ahmed AE (1987) "A novel mechanism for the enhancement of acetaminophen hepatotoxicity by phenobarbital." J Pharmacol Exp Ther, 240, p. 578-83
  3. Wright N, Prescott LF (1973) "Potentiation by previous drug therapy of hepatotoxicity following paracetamol overdose." Scott Med J, 18, p. 56-8
  4. Bock KW, Wiltfang J, Blume R, Ullrich D, Bircher J (1987) "Paracetamol as a test drug to determine glucuronide formation in man: effects of inducers and of smoking." Eur J Clin Pharmacol, 31, p. 677-83
View all 4 references

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Minor

ampicillin probenecid

Applies to: ampicillin / probenecid, ampicillin / probenecid

Probenecid may increase the plasma concentrations and half-lives of penicillins. The mechanism is competitive inhibition by probenecid of the renal tubular secretion of penicillins. While this interaction is often exploited to enhance the antibacterial effect of penicillins, toxicity may occur and should be considered if high penicillin dosages are administered intravenously.

References

  1. Sommers DK, Schoeman HS (1987) "Drug interactions with urate excretion in man?" Eur J Clin Pharmacol, 32, p. 499-502
  2. Waller ES, Sharanevych MA, Yakatan GJ (1982) "The effect of probenecid on nafcillin disposition." J Clin Pharmacol, 22, p. 482-9
  3. Shanson DC, McNabb R, Hajipieris P (1984) "The effect of probenecid on serum amoxycillin concentrations up to 18 hours after a single 3g oral dose of amoxycillin: possible implications for preventing endocarditis." J Antimicrob Chemother, 13, p. 629-32
  4. Sutherland R, Croydon EA, Rolinson GN (1972) "Amoxycillin: a new semi-synthetic penicillin." Br Med J, 3, p. 13-6
  5. Allen MB, Fitzpatrick RW, Barratt A, Cole RB (1990) "The use of probenecid to increase the serum amoxycillin levels in patients with bronchiectasis." Respir Med, 84, p. 143-6
  6. Gibaldi M, Schwartz MA (1968) "Apparent effect of probenecid on the distribution of penicillins in man." Clin Pharmacol Ther, 9, p. 345-9
View all 6 references

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Minor

probenecid acetaminophen

Applies to: ampicillin / probenecid, Allzital (acetaminophen / butalbital)

Probenecid may slightly increase the therapeutic effects of acetaminophen. At usual doses, however, no intervention appears to be necessary.

References

  1. Abernethy DR, Greenblatt DJ, Ameer B, Shader RI (1985) "Probenecid impairment of acetaminophen and lorazepam clearance: direct inhibition of ether glucuronide formation." J Pharmacol Exp Ther, 234, p. 345-9
  2. Kamali F, Fry JR, Bell GD (1987) "Salivary excretion of paracetamol in man." J Pharm Pharmacol, 39, p. 150-2

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Drug and food interactions

Major

acetaminophen food

Applies to: Allzital (acetaminophen / butalbital)

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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Major

butalbital food

Applies to: Allzital (acetaminophen / butalbital)

GENERALLY AVOID: Concurrent acute use of barbiturates and ethanol may result in additive CNS effects, including impaired coordination, sedation, and death. Tolerance of these agents may occur with chronic use. The mechanism is related to inhibition of microsomal enzymes acutely and induction of hepatic microsomal enzymes chronically.

MANAGEMENT: The combination of ethanol and barbiturates should be avoided.

References

  1. Gupta RC, Kofoed J (1966) "Toxological statistics for barbiturates, other sedatives, and tranquilizers in Ontario: a 10-year survey." Can Med Assoc J, 94, p. 863-5
  2. Misra PS, Lefevre A, Ishii H, Rubin E, Lieber CS (1971) "Increase of ethanol, meprobamate and pentobarbital metabolism after chronic ethanol administration in man and in rats." Am J Med, 51, p. 346-51
  3. Saario I, Linnoila M (1976) "Effect of subacute treatment with hypnotics, alone or in combination with alcohol, on psychomotor skills related to driving." Acta Pharmacol Toxicol (Copenh), 38, p. 382-92
  4. Stead AH, Moffat AC (1983) "Quantification of the interaction between barbiturates and alcohol and interpretation of fatal blood concentrations." Hum Toxicol, 2, p. 5-14
  5. Seixas FA (1979) "Drug/alcohol interactions: avert potential dangers." Geriatrics, 34, p. 89-102
View all 5 references

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Moderate

ampicillin food

Applies to: ampicillin / probenecid

ADJUST DOSING INTERVAL: Certain penicillins may exhibit reduced gastrointestinal absorption in the presence of food. The therapeutic effect of the antimicrobial may be reduced.

MANAGEMENT: The interacting penicillin should be administered one hour before or two hours after meals. Penicillin V and amoxicillin are not affected by food and may be given without regard to meals.

References

  1. Neu HC (1974) "Antimicrobial activity and human pharmacology of amoxicillin." J Infect Dis, 129, s123-31
  2. Welling PG, Huang H, Koch PA, Madsen PO (1977) "Bioavailability of ampicillin and amoxicillin in fasted and nonfasted subjects." J Pharm Sci, 66, p. 549-52
  3. McCarthy CG, Finland M (1960) "Absorption and excretion of four penicillins." N Engl J Med, 263, p. 315-26
  4. Cronk GA, Wheatley WB, Fellers GF, Albright H (1960) "The relationship of food intake to the absorption of potassium alpha-phenoxyethyl penicillin and potassium phenoxymethyl penicillin from the gastrointestinal tract." Am J Med Sci, 240, p. 219-25
  5. Klein JO, Sabath LD, Finland M (1963) "Laboratory studies on oxacillin. I: in vitro activity against staphylococci and some other bacterial pathogens. II: absorption and urinary excretion in normal young." Am J Med Sci, 245, p. 399-411
  6. Neuvonen PJ, Elonen E, Pentikainen PJ (1977) "Comparative effect of food on absorption of ampicillin and pivampicillin." J Int Med Res, 5, p. 71-6
View all 6 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.