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Drug Interactions between allopurinol and Synalgos-DC

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

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Interactions between your drugs

Moderate

allopurinol dihydrocodeine

Applies to: allopurinol and Synalgos-DC (aspirin / caffeine / dihydrocodeine)

MONITOR: Coadministration with alcohol or other central nervous system (CNS) depressants may enhance the sedative effects of allopurinol and increase the likelihood and/or severity of central nervous system (CNS) side effects, such as drowsiness, somnolence, vertigo, and ataxia.

MANAGEMENT: Caution for increased CNS adverse effects is advised if allopurinol is coadministered with alcohol, other CNS depressants, or agents that cause dizziness or vertigo. Patients should not drive, operate machinery, or engage in hazardous activities requiring mental alertness and motor coordination until they know how the medications affect them.

References (4)
  1. (2024) "Product Information. Allopurinol (Sandoz) (allopurinol)." Sandoz Pty Ltd
  2. (2021) "Product Information. Zyloric (allopurinol)." Aspen Pharma Trading Ltd
  3. (2021) "Product Information. Zyloprim (allopurinol)." AA Pharma Inc, 248178
  4. (2024) "Product Information. Allopurinol (allopurinol)." Actavis U.S. (Purepac Pharmaceutical Company)
Minor

allopurinol aspirin

Applies to: allopurinol and Synalgos-DC (aspirin / caffeine / dihydrocodeine)

The renal excretion allopurinol's active metabolite, oxypurinol, may be increased when coadministered with probenecid and/or large doses of salicylates (e.g., aspirin). At the same time, both probenecid and large doses of salicylates may have a hypouricemic effect; allopurinol may also inhibit probenecid metabolism. The clinical significance of this interaction is unknown. Patients should be monitored for altered effects of both allopurinol and probenecid.

References (10)
  1. Elion GB, Yu TF, Gutman AB, Hitchings GH (1968) "Renal clearance of oxipurinol, the chief metabolite of allopurinol." Am J Med, 45, p. 69-77
  2. Tjandramaga TB, Cucinell SA, Israili ZH, et al. (1972) "Observations on the disposition of probenecid in patients receiving allopurinol." Pharmacology, 8, p. 259-72
  3. Kelley WN (1976) "Current therapy of gout and hyperuricemia." Hosp Pract, 11, p. 69-76
  4. Stocker S (2011) "Pharmacokinetic and pharmacodynamic interaction between allopurinol and probenecid in patients with gout" J Rheumatol, 38, p. 904-910
  5. Reinders M (2007) "Biochemical effectiveness of allopurinol and allopurinol-probenecid in previously benzbromarone-treated gout patients" Clin Rheumatol, 26, p. 1459-1465
  6. Price GE (1963) "The Effects of Oral Salicylate on Serum Uric Acid Levels" Can Med Assoc J, 88, p. 1065-1067
  7. (2024) "Product Information. Allopurinol (Sandoz) (allopurinol)." Sandoz Pty Ltd
  8. (2021) "Product Information. Zyloric (allopurinol)." Aspen Pharma Trading Ltd
  9. (2021) "Product Information. Zyloprim (allopurinol)." AA Pharma Inc, 248178
  10. (2024) "Product Information. Allopurinol (allopurinol)." Actavis U.S. (Purepac Pharmaceutical Company)
Minor

aspirin caffeine

Applies to: Synalgos-DC (aspirin / caffeine / dihydrocodeine) and Synalgos-DC (aspirin / caffeine / dihydrocodeine)

One study has reported that coadministration of caffeine and aspirin lead to a 25% increase in the rate of appearance and 17% increase in maximum concentration of salicylate in the plasma. A significantly higher area under the plasma concentration time curve of salicylate was also reported when both drugs were administered together. The exact mechanism of this interaction has not been specified. Physicians and patients should be aware that coadministration of aspirin and caffeine may lead to higher salicylate levels faster.

References (1)
  1. Yoovathaworn KC, Sriwatanakul K, Thithapandha A (1986) "Influence of caffeine on aspirin pharmacokinetics." Eur J Drug Metab Pharmacokinet, 11, p. 71-6

Drug and food interactions

Moderate

allopurinol food

Applies to: allopurinol

ADJUST DOSING INTERVAL: The tolerability of allopurinol may be improved by giving it after a meal. Additionally, when the dose is greater than 300 mg, dividing the total daily dose into smaller doses administered more often may be appropriate to help minimize gastrointestinal irritation.

MONITOR: Concomitant use of allopurinol with central nervous system (CNS) depressants, including alcohol, may potentiate adverse effects such as somnolence and sedation.

MANAGEMENT: To improve tolerability, some manufacturers suggest administering allopurinol after a meal. Additionally, if the daily dose is greater than 300 mg, administering allopurinol in divided doses may help reduce gastrointestinal intolerance. Patients should also be counseled to avoid or limit consumption of alcohol and to avoid activities requiring mental alertness such as driving or operating hazardous machinery until they know how the medication affects them.

References (4)
  1. (2024) "Product Information. Allopurinol (Sandoz) (allopurinol)." Sandoz Pty Ltd
  2. (2021) "Product Information. Zyloric (allopurinol)." Aspen Pharma Trading Ltd
  3. (2021) "Product Information. Zyloprim (allopurinol)." AA Pharma Inc, 248178
  4. (2024) "Product Information. Allopurinol (allopurinol)." Actavis U.S. (Purepac Pharmaceutical Company)
Moderate

aspirin food

Applies to: Synalgos-DC (aspirin / caffeine / dihydrocodeine)

GENERALLY AVOID: The concurrent use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) and ethanol may lead to gastrointestinal (GI) blood loss. The mechanism may be due to a combined local effect as well as inhibition of prostaglandins leading to decreased integrity of the GI lining.

MANAGEMENT: Patients should be counseled on this potential interaction and advised to refrain from alcohol consumption while taking aspirin or NSAIDs.

References (1)
  1. (2002) "Product Information. Motrin (ibuprofen)." Pharmacia and Upjohn
Minor

caffeine food

Applies to: Synalgos-DC (aspirin / caffeine / dihydrocodeine)

The effect of grapefruit juice on the pharmacologic activity of caffeine is controversial. One report suggests that grapefruit juice increases the effect of caffeine. The proposed mechanism is inhibition of cytochrome P-450 metabolism of caffeine. However, a well-conducted pharmacokinetic/pharmacodynamic study did not demonstrate this effect. The clinical significance of this potential interaction is unknown.

References (2)
  1. (1995) "Grapefruit juice interactions with drugs." Med Lett Drugs Ther, 37, p. 73-4
  2. Maish WA, Hampton EM, Whitsett TL, Shepard JD, Lovallo WR (1996) "Influence of grapefruit juice on caffeine pharmacokinetics and pharmacodynamics." Pharmacotherapy, 16, p. 1046-52
Minor

aspirin food

Applies to: Synalgos-DC (aspirin / caffeine / dihydrocodeine)

One study has reported that coadministration of caffeine and aspirin lead to a 25% increase in the rate of appearance and 17% increase in maximum concentration of salicylate in the plasma. A significantly higher area under the plasma concentration time curve of salicylate was also reported when both drugs were administered together. The exact mechanism of this interaction has not been specified. Physicians and patients should be aware that coadministration of aspirin and caffeine may lead to higher salicylate levels faster.

References (1)
  1. Yoovathaworn KC, Sriwatanakul K, Thithapandha A (1986) "Influence of caffeine on aspirin pharmacokinetics." Eur J Drug Metab Pharmacokinet, 11, p. 71-6

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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