how does aspirin interact with metoprolol?

"Regarding ingredient interactions involving Metoprolol (found in Metoprolol Tartrate):

It's important to note that concurrent use with calcium salts might lower the effectiveness of atenolol and potentially other beta-blockers when taken orally. While the exact mechanism of this interaction is not fully understood, studies involving six healthy individuals showed that the presence of 500 mg of calcium (in lactate, carbonate, and gluconate forms) reduced the peak plasma concentration (Cmax) and overall exposure (AUC) of atenolol (100 mg) by approximately 51% and 32%, respectively. Additionally, the elimination half-life of atenolol increased by 44%.

Notably, the beta-blocking activity of atenolol, as indicated by its ability to inhibit exercise-induced tachycardia, was reduced twelve hours after calcium administration compared to atenolol alone. However, in a separate study involving six hypertensive patients over a 4-week period, there were no significant differences in blood pressure readings between treatments. Researchers hypothesized that the prolonged elimination half-life induced by calcium coadministration might have caused atenolol to accumulate over time, offsetting the decrease in bioavailability.

To manage this interaction, it is advisable to administer beta-blockers and calcium products at least 2 hours apart. Patients should also be monitored for any potential decrease in the effectiveness of beta-blockers following the addition of calcium therapy."

Aspirin + Food

"When using aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) concurrently with ethanol, it is advisable to exercise caution due to the potential risk of gastrointestinal (GI) bleeding. This effect may result from a combination of local effects and the inhibition of prostaglandins, which can compromise the integrity of the GI lining.

To manage this interaction, patients should be informed about the potential risks and advised to abstain from consuming alcohol while taking aspirin or NSAIDs."

Aspirin + Food

"A study has indicated that combining caffeine with aspirin results in a 25% acceleration in the appearance rate and a 17% increase in the maximum concentration of salicylate in the bloodstream. Furthermore, the combined administration of these drugs leads to a notably higher area under the plasma concentration-time curve of salicylate. However, the precise mechanism behind this interaction remains unspecified. It's important for both physicians and patients to recognize that the simultaneous use of aspirin and caffeine can elevate salicylate levels more rapidly."

Drug and Pregnancy Interactions

Metoprolol Tartrate + Pregnancy

For the ingredient Metoprolol (found in Metoprolol Tartrate):

In the United States, it's advised to use this medication during pregnancy only if absolutely necessary. In Australia and the UK, its use is generally not recommended unless the benefits clearly outweigh the risks. If it is used during pregnancy in these regions, it's recommended to administer the lowest effective dose and discontinue usage at least 2 to 3 days before the expected delivery date, if possible.

In terms of pregnancy categories:

• In Australia (TGA), Metoprolol is categorized as Category C, indicating potential harmful effects on the human fetus or neonate without causing malformations. These effects might be reversible, and additional information should be consulted for further details.
• In the United States (FDA), it falls under Category C as well, indicating adverse effects observed in animal studies with insufficient human data. However, in some cases, the potential benefits of using the drug during pregnancy might outweigh the risks, as determined by the healthcare provider.

Aspirin + Pregnancy

For the ingredient Aspirin:

• Use of 100 mg/day or less should be approached with caution.
• NSAIDs should be avoided after 20 weeks of pregnancy if the dosage exceeds 100 mg/day.

Pregnancy categories:

• Australia (TGA) categorizes Aspirin as Category C, indicating potential harm to the fetus or neonate without causing malformations.
• The US FDA does not assign a pregnancy category.

Risk Summary:

• NSAID use during the later stages of pregnancy may lead to premature closure of the fetal ductus arteriosus and fetal renal dysfunction, potentially causing oligohydramnios and neonatal renal impairment.

Guidelines and recommendations:

• Low-dose aspirin (e.g., 81 mg/day) may be used for specific pregnancy-related conditions, particularly for preeclampsia prevention, after consultation with healthcare providers.
• If NSAID use is necessary between 20 and 30 weeks of gestation, it should be limited to the lowest effective dose for the shortest duration possible.
• Prolonged NSAID use during pregnancy may lead to complications such as limb contractures and delayed lung maturation.

Advisory:

• Administration of NSAIDs during labor and delivery is not recommended due to potential delays in labor onset and increased bleeding risk.
• A study on the use of low-dose aspirin for preeclampsia prevention did not universally support its routine use, but it may have a role in the treatment of severe early-onset preeclampsia.

In summary, Aspirin use during pregnancy should be carefully considered, weighing potential benefits against risks, and should be used under medical supervision.

Drug and Breastfeeding Interactions

Metoprolol Tartrate + Breastfeeding

For the ingredient Metoprolol (found in Metoprolol Tartrate):

• In Australia and the UK, its use is generally not recommended unless the benefits outweigh the risks.
• In the US, caution is advised, but the drug has been utilized without apparent harmful effects.

Metoprolol is excreted into human milk, albeit in small amounts. However, it has been used without any apparent harmful effects on nursing infants.

For perspective, an infant consuming 1 liter of breast milk per day would receive less than 1 mg of the drug.

Aspirin + Breastfeeding

For the ingredient Aspirin:

• It's recommended that the benefits of using aspirin should outweigh the risks when considering breastfeeding.

Aspirin is excreted into human milk, albeit in small amounts. It's generally considered compatible with breastfeeding for occasional use and in low doses for anti-thrombosis. However, repeated use in normal doses and long-term use, especially in high doses, should be avoided.

Breastfed infants should be monitored for potential adverse effects such as hemolysis, prolonged bleeding time, and metabolic acidosis.

Low-dose aspirin (75 to 162 mg/day) is often deemed safe for breastfeeding by experts. Peak levels of salicylate in breast milk typically occur 2 to 6 hours after nursing, with reported peak milk salicylate levels observed up to 9 hours after maternal dosing.

However, large doses of aspirin may lead to adverse effects in nursing infants, including rashes, platelet abnormalities, and bleeding. Long-term and high-dose maternal use has been associated with metabolic acidosis in breastfed infants.

The risk of Reye's syndrome in infants with viral infections due to aspirin exposure during breastfeeding is unknown.

Conclusion

While aspirin and metoprolol do not exhibit a direct pharmacological interaction, both medications carry important considerations, particularly during pregnancy and breastfeeding.

Aspirin, when used in low doses, is generally deemed compatible with breastfeeding but requires caution for prolonged or high-dose use due to potential adverse effects on nursing infants. Metoprolol usage during pregnancy and breastfeeding should be approached cautiously, with its administration recommended only if the potential benefits outweigh the risks.

Healthcare professionals should carefully evaluate the individual circumstances of each patient, considering the potential risks and benefits associated with the use of aspirin and metoprolol during pregnancy and breastfeeding to ensure the well-being of both the mother and the child.