What to Know Before Taking a Substitute Medicine: 3 Key Things to Consider

Substitute medicines, commonly known as generic drugs, are alternatives to brand-name drugs. They contain the same active ingredients and are expected to provide similar therapeutic effects. Before switching to a substitute medicine, it’s important to understand how it works, why it may cost less, and what factors to consider to ensure your treatment remains safe and effective.

What Are Substitute Medicines?

Generic medicines are required by regulatory bodies like the U.S. Food and Drug Administration (FDA) in the US and the Central Drugs Standard Control Organisation (CDSCO) in India to be bioequivalent to their branded counterparts [1], [2]. This means they must have the same active ingredient, strength, dosage form, and route of administration. However, they are often sold at significantly lower prices because they skip the costly process of original drug development, clinical trials, and extensive marketing that is typically funded by the original patent holder [1].

Did You Know? The cost of generic medicines can be up to 80-85% lower due to savings on original research and marketing, offering a significant financial benefit to patients and healthcare systems [1]. This substantial reduction is a primary driver for healthcare cost-saving initiatives globally [3].

How Substitute Medicines Are Regulated

1. The FDA Action Plan (United States)

Substitute medications are generally considered to have the same risks and advantages as brand-name drugs once approved. The U.S. Food and Drug Administration (FDA) Generic Drugs Program conducts an exhaustive review of generic drug applications to ensure that they meet predetermined standards for quality, manufacturing, and bioequivalence and performs regular facility inspections [1].

The FDA announced the Drug Competition Action Plan in 2017 to accelerate market competition for generic medications, enhance the efficiency and transparency of the generic drug review process, and maintain the rigorous scientific standards of the generic drug program [4]. This plan aims to streamline the approval process for generics, particularly those facing complex hurdles, to bring more cost-effective options to patients faster.

2. The Indian Medical Association (IMA) Initiative (India)

Following the Prime Minister’s statement that physicians should prescribe generic medications, the Indian Medical Association (IMA) has reaffirmed its backing of the initiative.

However, the IMA has stressed that the government must guarantee the availability of generic medicines from stores like Jan Aushadhi Kendra and ensure their quality through adequate regulation and regular testing [5]. This highlights a crucial concern: the need for robust quality control mechanisms across the entire supply chain to maintain public trust in generic alternatives.

Essential Considerations Before Opting for a Substitute Medicine

You should consider the following three factors before opting for a substitute medicine.

1. Therapeutic Equivalence and Bioequivalence

The foundational requirement for a substitute medicine is bioequivalence. Bioequivalence means the generic version releases its active ingredient into the bloodstream at the same rate and extent as the brand-name drug. However, the inactive ingredients (excipients), such as binders, fillers, and coloring agents, can differ.

• Potential for Differences: In rare cases, these differences in inactive ingredients or the manufacturing process can affect the stability, absorption, or even cause allergic reactions in sensitive patients [6].
• Safety Precaution: It is essential to discuss any known allergies or sensitivities with your pharmacist or doctor before switching, as they can screen for potential issues with the excipients in the generic formulation.

2. Importance of Patient-Provider Communication and Safety

At your healthcare facility, or any pharmacy, the most prevalent justification for medication substitution is the lack of access or the prohibitive cost of the prescribed brand-name medication. While substitution is a viable option for continuity of care, it must be a collaborative decision.

• The Pharmacist’s Role: At the drug dispensary, with medical approval, a practitioner other than the one who initially prescribed the medicine may authorise the change. Given the impracticality of approaching the prescribing physician every time a change is requested, therapeutic substitution is a viable alternative that can provide better therapeutic outcomes and help prevent harm to the patient [6]. It is the pharmacist’s clinical responsibility to verify bioequivalence and screen for potential interactions or contraindications.
• Informed Consent: Patients should be informed about the substitution, the reasons for it, and have their questions answered. This transparency fosters patient trust and adherence to the new regimen, which is crucial for achieving better health outcomes.

3. Cost-Effectiveness and Supply Management

Opting for substitute medications instead of branded ones offers a considerable financial benefit without compromising the results for the vast majority of patients [3].

To ensure the systematic implementation of therapeutic substitution policies in institutional settings, it is essential to consult a Drug and Therapeutic Committee and all relevant stakeholders. This effort can not only bring a variety of general advantages, but it can also result in a better-managed inventory of necessary medicines.

• Beyond Cost: Sometimes, opting for therapeutic substitutions may not be the most economical option; however, it can be a time-efficient solution that ensures the patient receives necessary treatment without delay due to supply chain issues [6].

Steps to Use Substitute Medicines Safely and Effectively

Always consult your doctor or pharmacist before switching medicines, even if you believe they are identical. Some substitutions require careful consideration and potential dose adjustments based on individual health conditions and the specific drug class.

For example, in the diabetes drug class “gliptins,” most options require dose modification in patients with kidney disease, except for linagliptin. In such cases, a personalized selection by a pharmacist or physician is critical to prevent adverse effects like drug accumulation [7].

When advised by your healthcare provider and backed by regulatory standards, substitute medicines are a safe and effective alternative to brand-name drugs. Whether you’re managing chronic conditions or seeking to reduce treatment costs, informed substitution ensures your health remains a priority.

Disclaimer: This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. As a Licensed Pharmacist, I strongly advise you to always seek the direct guidance of a qualified healthcare professional, such as your physician or pharmacist, regarding any medical condition or before making any changes to your medication regimen. Reliance on any information provided in this article is solely at your own risk.

Expert Quote

“Substitute medicines are clinically equivalent to branded ones—as long as the right formulation is chosen for the patient’s condition and the patient is counselled on the change.”

-Dr. Sachin Singh

References

[1] U.S. Food and Drug Administration (FDA). (2021, March 16). Generic drugs: Questions & answers. https://www.fda.gov/drugs/frequently-asked-questions-popular-topics/generic-drugs-questions-answers#q1

[2] Central Drugs Standard Control Organisation (CDSCO). (n.d.). Indian pharmacopoeia (IP). Retrieved November 2, 2025, from https://cdsco.gov.in/opencms/opencms/en/Pharmacopoeia/

[3] Dylst, P., Vulto, A., & Simoens, S. (2015). The impact of generic and biosimilar medicines on the cost of healthcare: A review of the literature. Value in Health, 18(2), 207–213. https://doi.org/10.1016/j.jval.2014.12.002

[4] U.S. Food and Drug Administration (FDA). (2025, January 15). FDA Drug Competition Action Plan. https://www.fda.gov/drugs/guidance-compliance-regulatory-information/fda-drug-competition-action-plan

[5] Kairi, J. K., & Sharma, A. K. (2017). Substitutes of prescription medicines – A review of concerns relevant to doctors and patients. Journal of Clinical and Diagnostic Research, 11(8), IE01–IE04. https://doi.org/10.7860/jcdr/2017/28552.10439

[6] Kairi, J. K., & Sharma, A. K. (2017). Substitutes of prescription medicines – A review of concerns relevant to doctors and patients. Journal of Clinical and Diagnostic Research, 11(8), IE01–IE04. https://doi.org/10.7860/jcdr/2017/28552.10439

[7] Guedes, E. P., Hohl, A., De Melo, T. G., & Lauand, F. (2013). Linagliptin: Pharmacology, efficacy and safety in type 2 diabetes treatment. Diabetology & Metabolic Syndrome, 5(1), 25. https://doi.org/10.1186/1758-5996-5-25