Ferrous sulfate 325 mg tablet
Pro Research Analysisby 
Searched over 200M research papers
Ferrous Sulfate 325 mg Tablet: Clinical Implications and Drug Interactions
Introduction to Ferrous Sulfate 325 mg Tablets
Ferrous sulfate 325 mg tablets are commonly prescribed for the treatment of iron deficiency anemia. While effective in increasing iron levels, ferrous sulfate can interact with various medications, potentially altering their efficacy and leading to significant clinical implications.
Interaction with Levodopa and Carbidopa
Levodopa Bioavailability Reduction
Ferrous sulfate significantly reduces the bioavailability of levodopa, a medication used in the treatment of Parkinson's disease. A study demonstrated that co-administration of ferrous sulfate with levodopa resulted in a 55% decrease in peak levodopa levels and a 51% decrease in the area under the curve (AUC) for levodopa. This interaction is likely due to the chelation of iron by levodopa, which reduces its absorption.
Sinemet (Levodopa/Carbidopa) Interaction
Similarly, ferrous sulfate affects the bioavailability of Sinemet, a combination of levodopa and carbidopa. The AUC for levodopa decreased by 30%, and for carbidopa by over 75% when taken with ferrous sulfate. Although the reduction in Sinemet's efficacy was not statistically significant, the interaction could be clinically relevant for some patients.
Impact on Methyldopa Absorption and Blood Pressure Control
Ferrous sulfate also affects the absorption and metabolism of methyldopa, a medication used to manage hypertension. Co-administration with methyldopa led to a significant decrease in the proportion of "free" methyldopa excreted and an increase in methyldopa sulfate excretion. This interaction resulted in an 88% reduction in the quantity of "free" methyldopa excreted, leading to increased blood pressure in patients on chronic methyldopa therapy.
Effects on Ciprofloxacin Absorption
The absorption of ciprofloxacin, an antibiotic, is significantly impaired when taken with ferrous sulfate. A study found that the AUC for ciprofloxacin decreased substantially when co-administered with ferrous sulfate, with peak concentrations falling below the minimum inhibitory concentration for many susceptible organisms. This interaction suggests that ferrous sulfate can reduce the efficacy of ciprofloxacin, potentially leading to treatment failures.
Comparison with Other Iron Supplements
Ferric Citrate vs. Ferrous Sulfate in CKD Patients
In patients with chronic kidney disease (CKD) and iron deficiency, ferric citrate was found to be more effective than ferrous sulfate in increasing transferrin saturation (TSAT) and ferritin levels over 12 weeks. This suggests that ferric citrate may be a preferable option for iron supplementation in this patient population.
Intravenous vs. Oral Iron in CKD
A randomized trial comparing intravenous iron sucrose to oral ferrous sulfate in CKD patients with iron deficiency anemia found no significant difference in the decline of glomerular filtration rate (GFR) between the two groups. However, the intravenous iron group had a higher incidence of serious adverse events, including cardiovascular events and infections.
Adverse Effects and Tolerability
Ferrous sulfate can cause gastrointestinal side effects, which may lead to discontinuation of therapy. In a study involving athletes, a patient developed debilitating gastrointestinal side effects from ascorbic acid/ferrous sulfate combination therapy, leading to withdrawal from the study.
Conclusion
Ferrous sulfate 325 mg tablets are effective for treating iron deficiency anemia but can interact with various medications, potentially reducing their efficacy. These interactions are clinically significant and should be carefully managed. Alternative iron supplements, such as ferric citrate, may offer better outcomes in certain patient populations, such as those with CKD. Clinicians should be aware of these interactions and consider them when prescribing ferrous sulfate alongside other medications.
Sources and full results
Most relevant research papers on this topic