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Drug Interactions between amoxicillin / clarithromycin / vonoprazan and phenobarbital

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

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Interactions between your drugs

Major

PHENobarbital vonoprazan

Applies to: phenobarbital and amoxicillin / clarithromycin / vonoprazan

GENERALLY AVOID: Coadministration with potent inducers of CYP450 3A4 may significantly decrease the plasma concentrations of vonoprazan, which is metabolized by the isoenzyme. When coadministered with potent CYP450 3A4 inducers, vonoprazan systemic exposure (AUC) is predicted to decrease by 80%. Reduced efficacy of vonoprazan may occur.

MANAGEMENT: According to the manufacturer, concomitant use of vonoprazan with potent CYP450 3A4 inducers should be avoided.

References (2)
  1. (2022) "Product Information. Voquezna Dual Pak (amoxicillin-vonoprazan)." Phathom Pharmaceuticals, Inc
  2. (2022) "Product Information. Voquezna Triple Pak (amoxicillin/clarithromycin/vonoprazan)." Phathom Pharmaceuticals, Inc
Minor

amoxicillin clarithromycin

Applies to: amoxicillin / clarithromycin / vonoprazan and amoxicillin / clarithromycin / vonoprazan

Although some in vitro data indicate synergism between macrolide antibiotics and penicillins, other in vitro data indicate antagonism. When these drugs are given together, neither has predictable therapeutic efficacy. Data are available for erythromycin, although theoretically this interaction could occur with any macrolide. Except for monitoring of the effectiveness of antibiotic therapy, no special precautions appear to be necessary.

References (3)
  1. Strom J (1961) "Penicillin and erythromycin singly and in combination in scarlatina therapy and the interference between them." Antibiot Chemother, 11, p. 694-7
  2. Cohn JR, Jungkind DL, Baker JS (1980) "In vitro antagonism by erythromycin of the bactericidal action of antimicrobial agents against common respiratory pathogens." Antimicrob Agents Chemother, 18, p. 872-6
  3. Penn RL, Ward TT, Steigbigel RT (1982) "Effects of erythromycin in combination with penicillin, ampicillin, or gentamicin on the growth of listeria monocytogenes." Antimicrob Agents Chemother, 22, p. 289-94

Drug and food interactions

Major

PHENobarbital food

Applies to: phenobarbital

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 (5)
  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
Minor

clarithromycin food

Applies to: amoxicillin / clarithromycin / vonoprazan

Grapefruit juice may delay the gastrointestinal absorption of clarithromycin but does not appear to affect the overall extent of absorption or inhibit the metabolism of clarithromycin. The mechanism of interaction is unknown but may be related to competition for intestinal CYP450 3A4 and/or absorptive sites. In an open-label, randomized, crossover study consisting of 12 healthy subjects, coadministration with grapefruit juice increased the time to reach peak plasma concentration (Tmax) of both clarithromycin and 14-hydroxyclarithromycin (the active metabolite) by 80% and 104%, respectively, compared to water. Other pharmacokinetic parameters were not significantly altered. This interaction is unlikely to be of clinical significance.

References (1)
  1. Cheng KL, Nafziger AN, Peloquin CA, Amsden GW (1998) "Effect of grapefruit juice on clarithromycin pharmacokinetics." Antimicrob Agents Chemother, 42, p. 927-9

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

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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