Drug-drug interactions happen when two medicines affect each other’s performance when taken together. These interactions can change how well the medicines work, either making them stronger or weaker, or they can cause unexpected side effects. Sometimes, they might even lead to new effects that wouldn’t occur if each medicine was taken on its own.
Here are some common effects of drug-drug interactions:
Increased Drug Effectiveness: Some interactions may enhance the therapeutic effect of a drug. While this can sometimes be beneficial, it can also lead to toxicity if the increased effect exceeds therapeutic goals.
Reduced Drug Effectiveness: An interaction may reduce the effectiveness of a drug, leading to suboptimal treatment outcomes. For example, certain drugs can induce the enzymes that metabolize another drug, leading to its rapid breakdown and insufficient levels to achieve its therapeutic effect.
Increased Side Effects and Toxicity: Drug interactions can lead to higher levels of a drug than intended, increasing the risk of side effects and toxicity. This can happen, for instance, if one drug inhibits the metabolism of another, causing the latter to accumulate in the body.
New or Unexpected Adverse Reactions: Sometimes, drug interactions produce new effects that neither drug alone would cause. This can include unusual side effects or toxicities not typically associated with either medication independently.
Delayed Drug Absorption: Some interactions can delay the absorption of a drug, slowing the onset of its action. This might reduce the drug’s effectiveness, especially if timed action is crucial for the therapeutic outcome.
Accelerated Drug Absorption: Conversely, interactions can also enhance the absorption of a drug, potentially leading to too rapid onset of action or increased risk of side effects.
Alterations in Drug Distribution: Interactions can change how drugs are distributed within the body, affecting how much drug reaches the site of action or other tissues, potentially altering effectiveness and side effect profiles.
Given these potential effects, it’s crucial for healthcare providers to review all medications a patient is taking, including over-the-counter drugs, supplements, and herbal products, to identify and manage possible drug-drug interactions. Monitoring, dosage adjustments, changing medications, or implementing other safety measures can help manage the risks associated with drug interactions.
The exact number of people who die each year from drug interactions can be challenging to determine due to various factors, including underreporting, misdiagnosis, and the complexity of attributing a death specifically to a drug interaction versus other possible causes. However, adverse drug reactions (ADRs), which include deaths from drug interactions, are a significant public health concern.
Estimates from studies suggest that adverse drug reactions are among the leading causes of death in many countries. For instance, a study published in the Journal of the American Medical Association (JAMA) suggested that ADRs could be considered a leading cause of death in the United States, with tens of thousands of deaths annually attributed to this cause. However, it’s important to note that these figures encompass all adverse drug reactions, not just those stemming from drug interactions.
The risk of death from drug interactions can be higher in certain populations, such as the elderly, who often take multiple medications for various health issues, increasing the potential for interactions.
Efforts to improve medication safety, including electronic prescribing systems, medication review processes, and patient education, aim to reduce the incidence of harmful drug interactions and the deaths associated with them.
To minimize the risk of adverse drug interactions:
Always inform healthcare providers about all medications being taken, including over-the-counter drugs, supplements, and herbal products.
Follow the prescription and advice given by healthcare providers closely.
Read medication labels and patient information leaflets for potential interaction warnings.
Consult with healthcare providers or pharmacists before starting new medications or supplements.
Sources:
Insani WN, Whittlesea C, Alwafi H, Man KKC, Chapman S, Wei L. Prevalence of adverse drug reactions in the primary care setting: A systematic review and meta-analysis. PLoS One. 2021 May 26;16(5):e0252161. doi: 10.1371/journal.pone.0252161. PMID: 34038474; PMCID: PMC8153435.









