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Drug Interactions between Acid Reducer Plus Antacid and Malarone

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

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Interactions between your drugs

Moderate

calcium carbonate proguanil

Applies to: Acid Reducer Plus Antacid (calcium carbonate / famotidine / magnesium hydroxide) and Malarone (atovaquone / proguanil)

ADJUST DOSING INTERVAL: The concomitant administration of magnesium trisilicate may significantly reduce the bioavailability of proguanil by reducing its absorption. Therapeutic failure may result. Other antacids and absorbent antidiarrheals may also interact with proguanil.

MANAGEMENT: Antacids or antidiarrheals and proguanil should be taken at least 2 to 3 hours apart.

References (1)
  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
Moderate

magnesium hydroxide proguanil

Applies to: Acid Reducer Plus Antacid (calcium carbonate / famotidine / magnesium hydroxide) and Malarone (atovaquone / proguanil)

ADJUST DOSING INTERVAL: The concomitant administration of magnesium trisilicate may significantly reduce the bioavailability of proguanil by reducing its absorption. Therapeutic failure may result. Other antacids and absorbent antidiarrheals may also interact with proguanil.

MANAGEMENT: Antacids or antidiarrheals and proguanil should be taken at least 2 to 3 hours apart.

References (1)
  1. Cerner Multum, Inc. "UK Summary of Product Characteristics."
Minor

famotidine calcium carbonate

Applies to: Acid Reducer Plus Antacid (calcium carbonate / famotidine / magnesium hydroxide) and Acid Reducer Plus Antacid (calcium carbonate / famotidine / magnesium hydroxide)

Antacids and some aluminum, calcium, and magnesium salts may decrease the plasma concentrations of H2-receptor antagonists during oral coadministration. The mechanism of interaction is unknown, but may involve reduced oral absorption due to increased gastric pH. Study data vary, with no changes to nearly 60% reductions in systemic exposures (AUCs) reported for cimetidine, famotidine, and ranitidine. The clinical significance has not been established. As a precaution, patients may consider taking H2-receptor antagonists one to two hours before antacids.

References (12)
  1. Donn KH, Eshelman FN, Plachetka JR, et al. (1984) "The effects of antacid and propantheline on the absorption of oral ranitidine." Pharmacotherapy, 4, p. 89-92
  2. Albin H, Vincon G, Demotes-Mainard F, et al. (1984) "Effect of aluminium phosphate on the bioavailability of cimetidine and prednisolone." Eur J Clin Pharmacol, 26, p. 271-3
  3. Lin JH, Chremos AN, Kanovsky SM, Schwartz S, Yeh KC, Kann J (1987) "Effects of antacids and food on absorption of famotidine." Br J Clin Pharmacol, 24, p. 551-3
  4. Bodemar G, Norlander B, Walan A (1979) "Diminished absorption of cimetidine caused by antacids." Lancet, 02/24/79, p. 444-5
  5. Steinberg WM, Lewis JH, Katz DM (1982) "Antacids inhibit absorption of cimetidine." N Engl J Med, 307, p. 400-4
  6. Barzaghi N, Gatti G, Crema F, Perucca E (1989) "Impaired bioavailability of famotidine given concurrently with a potent antacid." J Clin Pharmacol, 29, p. 670-2
  7. Russell WL, Lopez LM, Normann SA, et al. (1984) "Effect of antacids on predicted steady-state cimetidine concentrations." Dig Dis Sci, 29, p. 385-9
  8. Shelly DW, Doering PL, Russell WL, Guild RT, Lopez LM, Perrin J (1986) "Effect of concomitant antacid administration on plasma cimetidine concentrations during repetitive dosing." Drug Intell Clin Pharm, 20, p. 792-5
  9. Albin H, Vincon G, Begaud B, Bistue C, Perez P (1987) "Effect of aluminum phosphate on the bioavailability of ranitidine." Eur J Clin Pharmacol, 32, p. 97-9
  10. Mihaly GW, Marino AT, Webster LK, Jones DB, Louis WJ, Smallwood RA (1982) "High dose of antacid (Mylanta II) reduces bioavailability of ranitidine." Br Med J, 285, p. 998-9
  11. Covington TR, eds., Lawson LC, Young LL (1993) "Handbook of Nonprescription Drugs." Washington, DC: American Pharmaceutical Association
  12. Bachmann KA, Sullivan TJ, Jauregui L, Reese J, Miller K, Levine L (1994) "Drug interactions of h-2-receptor antagonists." Scand J Gastroenterol, 29, p. 14-9
Minor

famotidine magnesium hydroxide

Applies to: Acid Reducer Plus Antacid (calcium carbonate / famotidine / magnesium hydroxide) and Acid Reducer Plus Antacid (calcium carbonate / famotidine / magnesium hydroxide)

Antacids and some aluminum, calcium, and magnesium salts may decrease the plasma concentrations of H2-receptor antagonists during oral coadministration. The mechanism of interaction is unknown, but may involve reduced oral absorption due to increased gastric pH. Study data vary, with no changes to nearly 60% reductions in systemic exposures (AUCs) reported for cimetidine, famotidine, and ranitidine. The clinical significance has not been established. As a precaution, patients may consider taking H2-receptor antagonists one to two hours before antacids.

References (12)
  1. Donn KH, Eshelman FN, Plachetka JR, et al. (1984) "The effects of antacid and propantheline on the absorption of oral ranitidine." Pharmacotherapy, 4, p. 89-92
  2. Albin H, Vincon G, Demotes-Mainard F, et al. (1984) "Effect of aluminium phosphate on the bioavailability of cimetidine and prednisolone." Eur J Clin Pharmacol, 26, p. 271-3
  3. Lin JH, Chremos AN, Kanovsky SM, Schwartz S, Yeh KC, Kann J (1987) "Effects of antacids and food on absorption of famotidine." Br J Clin Pharmacol, 24, p. 551-3
  4. Bodemar G, Norlander B, Walan A (1979) "Diminished absorption of cimetidine caused by antacids." Lancet, 02/24/79, p. 444-5
  5. Steinberg WM, Lewis JH, Katz DM (1982) "Antacids inhibit absorption of cimetidine." N Engl J Med, 307, p. 400-4
  6. Barzaghi N, Gatti G, Crema F, Perucca E (1989) "Impaired bioavailability of famotidine given concurrently with a potent antacid." J Clin Pharmacol, 29, p. 670-2
  7. Russell WL, Lopez LM, Normann SA, et al. (1984) "Effect of antacids on predicted steady-state cimetidine concentrations." Dig Dis Sci, 29, p. 385-9
  8. Shelly DW, Doering PL, Russell WL, Guild RT, Lopez LM, Perrin J (1986) "Effect of concomitant antacid administration on plasma cimetidine concentrations during repetitive dosing." Drug Intell Clin Pharm, 20, p. 792-5
  9. Albin H, Vincon G, Begaud B, Bistue C, Perez P (1987) "Effect of aluminum phosphate on the bioavailability of ranitidine." Eur J Clin Pharmacol, 32, p. 97-9
  10. Mihaly GW, Marino AT, Webster LK, Jones DB, Louis WJ, Smallwood RA (1982) "High dose of antacid (Mylanta II) reduces bioavailability of ranitidine." Br Med J, 285, p. 998-9
  11. Covington TR, eds., Lawson LC, Young LL (1993) "Handbook of Nonprescription Drugs." Washington, DC: American Pharmaceutical Association
  12. Bachmann KA, Sullivan TJ, Jauregui L, Reese J, Miller K, Levine L (1994) "Drug interactions of h-2-receptor antagonists." Scand J Gastroenterol, 29, p. 14-9

Drug and food/lifestyle interactions

Moderate

calcium carbonate food/lifestyle

Applies to: Acid Reducer Plus Antacid (calcium carbonate / famotidine / magnesium hydroxide)

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 (6)
  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 Española de Medicamentos y Productos Sanitarios Healthcare (2008) Centro de información 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
Moderate

atovaquone food/lifestyle

Applies to: Malarone (atovaquone / proguanil)

ADJUST DOSING INTERVAL: Food, particularly high-fat food, significantly enhances the oral absorption and bioavailability of atovaquone. In 16 healthy volunteers, administration of a single 750 mg dose of atovaquone suspension following a standard breakfast (23 g fat: 610 kCal) resulted in an approximately 3.4-fold increase in the mean peak plasma concentration (Cmax) and a 2.5-fold increase in the mean area under the plasma concentration-time curve (AUC) of atovaquone compared to administration following an overnight fast. In a study consisting of 19 HIV-infected volunteers receiving atovaquone suspension 500 mg/day, Cmax and AUC of atovaquone increased by 72% and 66%, respectively, in the fed state relative to the fasting state.

MANAGEMENT: To ensure maximal oral absorption, atovaquone products (suspension, tablet, or in combination with proguanil) should be administered with a meal or milky drink, or enteral nutrition at the same time(s) each day. Because plasma atovaquone concentrations have been shown to correlate with the likelihood of successful treatment and in some cases, survival, alternative therapies may be appropriate for patients who have difficulty taking atovaquone with food.

References (3)
  1. (2001) "Product Information. Mepron (atovaquone)." Glaxo Wellcome
  2. (2001) "Product Information. Malarone (atovaquone-proguanil)." Glaxo Wellcome
  3. 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
Minor

famotidine food/lifestyle

Applies to: Acid Reducer Plus Antacid (calcium carbonate / famotidine / magnesium hydroxide)

H2 antagonists may reduce the clearance of nicotine. Cimetidine, 600 mg given twice a day for two days, reduced clearance of an intravenous nicotine dose by 30%. Ranitidine, 300 mg given twice a day for two days, reduced clearance by 10%. The clinical significance of this interaction is not known. Patients should be monitored for increased nicotine effects when using the patches or gum for smoking cessation and dosage adjustments should be made as appropriate.

References (1)
  1. Bendayan R, Sullivan JT, Shaw C, Frecker RC, Sellers EM (1990) "Effect of cimetidine and ranitidine on the hepatic and renal elimination of nicotine in humans." Eur J Clin Pharmacol, 38, p. 165-9

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.

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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

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