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Drug Interactions between aspirin / diphenhydramine / phenylpropanolamine and piroxicam

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

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Interactions between your drugs

Major

aspirin piroxicam

Applies to: aspirin / diphenhydramine / phenylpropanolamine and piroxicam

GENERALLY AVOID: The use of piroxicam in combination with another nonsteroidal anti-inflammatory drug (NSAID) may increase the risk of serious and potentially fatal gastrointestinal (GI) toxicity, including inflammation, bleeding, ulceration, and perforation of the esophagus, stomach, or intestines. These events can occur at any time during NSAID use, with or without warning symptoms, but the incidence may increase with dosage and duration of therapy. Administration of piroxicam at dosages greater than 20 mg per day carries an increased risk of GI side effects, and evidence from observational studies suggests that piroxicam may also be associated with a higher risk of serious GI toxicity relative to other NSAIDs. In clinical trials of several months to two years duration, NSAID-associated upper GI ulcers, gross bleeding, or perforation occurred in approximately 1% of patients treated for 3 to 6 months and in 2% to 4% of patients treated for one year. Patients with a prior history of peptic ulcer disease and/or GI bleeding have a greater than 10-fold increased risk of developing a GI bleed during NSAID use compared to patients without a history. Additional risk factors include advanced age (especially over 70 years), Helicobacter pylori infection, excessive alcohol use, smoking, a history of GI inflammatory conditions, advanced liver disease, coagulopathy, and poor general health status. GI toxicity aside, clinical studies have also failed to demonstrate greater therapeutic benefit from the coadministration of piroxicam with another NSAID than the use of piroxicam alone.

MANAGEMENT: Concomitant use of piroxicam with other NSAIDs, except for low-dose aspirin for cardiovascular prophylaxis, should generally be avoided. Patients treated with a NSAID should be advised to take it with food and to immediately report signs and symptoms of GI ulceration or bleeding such as severe abdominal pain, dizziness, lightheadedness, and the appearance of black, tarry stools. The lowest effective dosage should be used for the shortest possible duration. Selective use of prophylactic anti-ulcer therapy (e.g., misoprostol, proton pump inhibitors) may be considered in high-risk patients.

References (4)
  1. (2023) "Product Information. APO Piroxicam (piroxicam)." Apotex Incorporated
  2. (2024) "Product Information. Feldene (piroxicam)." Pfizer Ltd
  3. (2024) "Product Information. Feldene (piroxicam)." Pfizer U.S. Pharmaceuticals Group, SUPPL-53
  4. (2024) "Product Information. moBILis (piroxicam)." Alphapharm Pty Ltd

Drug and food interactions

Moderate

phenylpropanolamine food

Applies to: aspirin / diphenhydramine / phenylpropanolamine

GENERALLY AVOID: Alcohol may potentiate the central nervous system and cardiovascular effects of centrally-acting appetite suppressants. In one study, concurrent administration of methamphetamine (30 mg intravenously) and ethanol (1 gm/kg orally over 30 minutes) increased heart rate by 24 beats/minute compared to methamphetamine alone. This increases cardiac work and myocardial oxygen consumption, which may lead to more adverse cardiovascular effects than either agent alone. Subjective effects of ethanol were diminished in the eight study subjects, but those of methamphetamine were not affected. The pharmacokinetics of methamphetamine were also unaffected except for a decrease in the apparent volume of distribution at steady state.

MANAGEMENT: Concomitant use of centrally-acting appetite suppressants and alcohol should be avoided if possible, especially in patients with a history of cardiovascular disease. Patients should be counselled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

References (3)
  1. Mendelson J, Jones RT, Upton R, Jacob P 3rd (1995) "Methamphetamine and ethanol interactions in humans." Clin Pharmacol Ther, 57, p. 559-68
  2. (2001) "Product Information. Didrex (benzphetamine)." Pharmacia and Upjohn
  3. (2012) "Product Information. Suprenza (phentermine)." Akrimax Pharmaceuticals
Moderate

aspirin food

Applies to: aspirin / diphenhydramine / phenylpropanolamine

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
Moderate

diphenhydrAMINE food

Applies to: aspirin / diphenhydramine / phenylpropanolamine

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)
  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
Moderate

piroxicam food

Applies to: piroxicam

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
Moderate

phenylpropanolamine food

Applies to: aspirin / diphenhydramine / phenylpropanolamine

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 (7)
  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
Minor

aspirin food

Applies to: aspirin / diphenhydramine / phenylpropanolamine

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

Therapeutic duplication is the use of more than one medicine from the same drug category or therapeutic class to treat the same condition. This can be intentional in cases where drugs with similar actions are used together for demonstrated therapeutic benefit. It can also be unintentional in cases where a patient has been treated by more than one doctor, or had prescriptions filled at more than one pharmacy, and can have potentially adverse consequences.

Duplication

Nonsteroidal anti-inflammatories

Therapeutic duplication

The recommended maximum number of medicines in the 'nonsteroidal anti-inflammatories' category to be taken concurrently is usually one. Your list includes two medicines belonging to the 'nonsteroidal anti-inflammatories' category:

  • aspirin/diphenhydramine/phenylpropanolamine
  • piroxicam

Note: In certain circumstances, the benefits of taking this combination of drugs may outweigh any risks. Always consult your healthcare provider before making changes to your medications or dosage.

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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