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Drug Interactions between aluminum hydroxide / calcium carbonate / magnesium hydroxide / simethicone and amprenavir

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

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Interactions between your drugs

Moderate

calcium carbonate amprenavir

Applies to: aluminum hydroxide / calcium carbonate / magnesium hydroxide / simethicone and amprenavir

ADJUST DOSING INTERVAL: Concurrent administration of antacids or other agents with acid-neutralizing effects may decrease the oral bioavailability of amprenavir and reduce its concentrations in plasma. Amprenavir solubility decreases with increasing pH, thus reduction in gastric acidity may interfere with dissolution of the drug. Subtherapeutic antiretroviral drug levels may lead to reduced viral susceptibility and development of resistance. In contrast, the prodrug fosamprenavir appears to be less affected by antacids. Administration of a single 1400 mg dose with 30 mL of antacid (Maalox TC) resulted in decreased peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of amprenavir by 35% and 18%, respectively. However, trough plasma concentration (Cmin) increased by 14%.

MANAGEMENT: Amprenavir should be administered at least 1 hour before or after antacids or other oral preparations containing antacids (e.g., didanosine buffered tablets or pediatric oral solution).

References

  1. (2001) "Product Information. Agenerase (amprenavir)." Glaxo Wellcome
  2. (2003) "Product Information. Lexiva (fosamprenavir)." GlaxoSmithKline

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Moderate

aluminum hydroxide amprenavir

Applies to: aluminum hydroxide / calcium carbonate / magnesium hydroxide / simethicone and amprenavir

ADJUST DOSING INTERVAL: Concurrent administration of antacids or other agents with acid-neutralizing effects may decrease the oral bioavailability of amprenavir and reduce its concentrations in plasma. Amprenavir solubility decreases with increasing pH, thus reduction in gastric acidity may interfere with dissolution of the drug. Subtherapeutic antiretroviral drug levels may lead to reduced viral susceptibility and development of resistance. In contrast, the prodrug fosamprenavir appears to be less affected by antacids. Administration of a single 1400 mg dose with 30 mL of antacid (Maalox TC) resulted in decreased peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of amprenavir by 35% and 18%, respectively. However, trough plasma concentration (Cmin) increased by 14%.

MANAGEMENT: Amprenavir should be administered at least 1 hour before or after antacids or other oral preparations containing antacids (e.g., didanosine buffered tablets or pediatric oral solution).

References

  1. (2001) "Product Information. Agenerase (amprenavir)." Glaxo Wellcome
  2. (2003) "Product Information. Lexiva (fosamprenavir)." GlaxoSmithKline

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Moderate

magnesium hydroxide amprenavir

Applies to: aluminum hydroxide / calcium carbonate / magnesium hydroxide / simethicone and amprenavir

ADJUST DOSING INTERVAL: Concurrent administration of antacids or other agents with acid-neutralizing effects may decrease the oral bioavailability of amprenavir and reduce its concentrations in plasma. Amprenavir solubility decreases with increasing pH, thus reduction in gastric acidity may interfere with dissolution of the drug. Subtherapeutic antiretroviral drug levels may lead to reduced viral susceptibility and development of resistance. In contrast, the prodrug fosamprenavir appears to be less affected by antacids. Administration of a single 1400 mg dose with 30 mL of antacid (Maalox TC) resulted in decreased peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of amprenavir by 35% and 18%, respectively. However, trough plasma concentration (Cmin) increased by 14%.

MANAGEMENT: Amprenavir should be administered at least 1 hour before or after antacids or other oral preparations containing antacids (e.g., didanosine buffered tablets or pediatric oral solution).

References

  1. (2001) "Product Information. Agenerase (amprenavir)." Glaxo Wellcome
  2. (2003) "Product Information. Lexiva (fosamprenavir)." GlaxoSmithKline

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Drug and food interactions

Major

aluminum hydroxide food

Applies to: aluminum hydroxide / calcium carbonate / magnesium hydroxide / simethicone

GENERALLY AVOID: The concomitant administration of aluminum-containing products (e.g., antacids and phosphate binders) and citrates may significantly increase serum aluminum concentrations, resulting in toxicity. Citrates or citric acid are contained in numerous soft drinks, citrus fruits, juices, and effervescent and dispersible drug formulations. Citrates enhance the gastrointestinal absorption of aluminum by an unknown mechanism, which may involve the formation of a soluble aluminum-citrate complex. Various studies have reported that citrate increases aluminum absorption by 4.6- to 50-fold in healthy subjects. Patients with renal insufficiency are particularly at risk of developing hyperaluminemia and encephalopathy. Fatalities have been reported. Patients with renal failure or on hemodialysis may also be at risk from soft drinks and effervescent and dispersible drug formulations that contain citrates or citric acid. It is unknown what effect citrus fruits or juices would have on aluminum absorption in healthy patients.

MANAGEMENT: The concomitant use of aluminum- and citrate-containing products and foods should be avoided by renally impaired patients. Hemodialysis patients should especially be cautioned about effervescent and dispersible over-the-counter remedies and soft drinks. Some experts also recommend that healthy patients should separate doses of aluminum-containing antacids and citrates by 2 to 3 hours.

ADJUST DOSING INTERVAL: The administration of aluminum-containing antacids with enteral nutrition may result in precipitation, formation of bezoars, and obstruction of feeding tubes. The proposed mechanism is the formation of an insoluble complex between the aluminum and the protein in the enteral feeding. Several cases of esophageal plugs and nasogastric tube obstructions have been reported in patients receiving high-protein liquids and an aluminum hydroxide-magnesium hydroxide antacid or an aluminum hydroxide antacid.

MANAGEMENT: Some experts recommend that antacids should not be mixed with or given after high protein formulations, that the antacid dose should be separated from the feeding by as much as possible, and that the tube should be thoroughly flushed before administration.

References

  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. Wohlt PD, Zheng L, Gunderson S, Balzar SA, Johnson BD, Fish JT (2009) "Recommendations for the use of medications with continuous enteral nutrition." Am J Health Syst Pharm, 66, p. 1438-67

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Moderate

calcium carbonate food

Applies to: aluminum hydroxide / calcium carbonate / magnesium hydroxide / simethicone

ADJUST DOSING INTERVAL: Administration with food may increase the absorption of calcium. However, foods high in oxalic acid (spinach or rhubarb), or phytic acid (bran and whole grains) may decrease calcium absorption.

MANAGEMENT: Calcium may be administered with food to increase absorption. Consider withholding calcium administration for at least 2 hours before or after consuming foods high in oxalic acid or phytic acid.

References

  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  2. Canadian Pharmacists Association (2006) e-CPS. http://www.pharmacists.ca/function/Subscriptions/ecps.cfm?link=eCPS_quikLink
  3. Cerner Multum, Inc. "Australian Product Information."
  4. Agencia EspaƱola de Medicamentos y Productos Sanitarios Healthcare (2008) Centro de informaciĆ³n online de medicamentos de la AEMPS - CIMA. https://cima.aemps.es/cima/publico/home.html
  5. Mangels AR (2014) "Bone nutrients for vegetarians." Am J Clin Nutr, 100, epub
  6. Davies NT (1979) "Anti-nutrient factors affecting mineral utilization." Proc Nutr Soc, 38, p. 121-8
View all 6 references

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Moderate

amprenavir food

Applies to: amprenavir

GENERALLY AVOID: Administration with a high-fat meal may decrease the oral bioavailability of amprenavir. The mechanism is unknown. In healthy volunteers, consumption of a standardized high-fat meal decreased the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of amprenavir (1200 mg single oral dose) by 36% and 21%, respectively, compared to administration in the fasted state. The time to reach Cmax (Tmax) was increased 44% following a high-fat meal.

Grapefruit juice does not appear to significantly affect the pharmacokinetics of amprenavir. In 12 healthy volunteers, administration with grapefruit juice (200 mL) decreased the mean peak plasma concentration (Cmax) of amprenavir (1200 mg single oral dose) by 22% compared to water. The median time to reach Cmax (Tmax) was prolonged from 0.75 to 1.13 hours. These pharmacokinetic changes are not thought to be clinically significant, since antiretroviral response is more closely associated with systemic exposure (AUC) and trough plasma concentration (Cmin), which were not affected in the study.

MANAGEMENT: Amprenavir may be taken with or without food, but should not be taken with a high-fat meal.

References

  1. (2001) "Product Information. Agenerase (amprenavir)." Glaxo Wellcome
  2. Demarles D, Gillotin C, Bonaventure-Paci S, Vincent I, Fosse S, Taburet AM (2002) "Single-dose pharmacokinetics of amprenavir coadministered with grapefruit juice." Antimicrob Agents Chemother, 46, p. 1589-1590

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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.


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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.