Liability for Prescription Drug Interactions

What will a jury believe in terms of liability and damages when a patient claims harm against his healthcare provider for a drug interaction? 

Written by Doug Stephan and published in M.D. Update  


According to the law, a healthcare provider must exercise “ordinary” care in delivery of healthcare services.  That means the provider must not engage in conduct that would create an “unreasonable” risk of harm to the patient. When this standard is not met, there is a “breach” of the healthcare provider’s legal duty, and the provider may be liable for damages to the patient.


When a patient sues his/her healthcare provider for injuries arising out of medical treatment, the cause of action is generally one for “medical malpractice.”  The cause of action is the same when a patient complains that he/she has been injured as the result of a prescription drug interaction. 


For the purposes of this article, a “drug interaction” is defined as an adverse reaction that occurs when two drugs chemically overlap.  One example would be an elderly patient with psoriatic arthritis who takes Methotrexate as prescribed by her rheumatologist.  Perhaps she is seen by her family medicine physician for a serious infection and is prescribed an antibiotic.  After taking a couple days’ worth of the antibiotic, the patient becomes very weak and sick.  She reports to the hospital where she is diagnosed with a rare, but serious, drug interaction between the Methotrexate and antibiotic. She files a lawsuit, claiming that her hospitalization resulted from the family medicine physician committed medical malpractice when he prescribed her the antibiotic.


Interactions may also exist between drugs and food as well as drugs and medicinal plants or herbs.  There is increasing evidence that over-the-counter herbal and botanical supplements can interfere with a wide range of prescription medications. 


For a plaintiff to succeed on a medical malpractice claim involving a prescription drug interaction, he/she must prove duty, breach of that duty, causation, and injury. 


The first of these four elements requires the patient to prove that the prescribing physician owed a duty to the patient.  This condition is almost always met where the physician has prescribed one of the drugs involved in the prescription drug interaction.


Once the presence of a duty is established, the patient must demonstrate that the physician did not act with ordinary care when prescribing the drug, and that the provider’s failure to do so was the direct cause of damage to the patient.  In other words, the drug interaction must be caused by the physician’s actions and not some intervening act or condition. 


Finally, the patient must prove that he/she has suffered “damages” as the result of the drug interaction.  While some drug interactions might directly cause minor discomfort or inconvenience to the patient, the law generally confines itself to compensating serious harm, such as serious illness, or incapacitation, lost wages, and medical bills. 


With an ever-growing number of prescription medications available in the marketplace, the courts have seen a rise in medical claims arising from prescription drug interactions.  How can a physician avoid being sued for medical malpractice arising out of prescription drug interactions? The following are some practical tips for keeping yourself out of court:   


1. Conform your prescribing practices to the current standards of medical care.


Providing high-quality medical care is always the best defense against claims of medical malpractice.  With respect to prescribing medications, this means choosing a medication that is tailored to, and takes into account, all of the patient’s clinical conditions.  Maintain an updated list of the patient’s current medications, including those prescribed by other physicians.  This list should also include over-the-counter medications, supplements used by the patient, and alcohol/tobacco/illicit drugs.  Physicians should make sure that lab work is ordered and reviewed prior to starting certain medications.  Also, consider coordinating suspension of a medication used for a chronic condition if necessary to achieve immediate short term relief of an acute condition (e.g. infection).


2.         Maintain accurate and detailed documentation of prescribing practices.


Proper documentation of prescription drug interactions is critical in the defense of malpractice claims.  Physicians must document what service was provided, when and by whom it was provided, and the medications prescribed, including the dose, directions and number of refills provided.  Most physicians are careful to weigh the reasons for choosing one medication over another; unfortunately, they may neglect to document these reasons in the patient’s medical record.  A well-reasoned choice on the part of the physician may tend to prove that he or she acted with ordinary care.


3.         Engage in interactive informed consent discussions that allocate appropriate responsibility to the patient.


All good physicians educate their patients about new treatments and medication, but the depth of that education varies according to several factors.  All patients should be told the common side effects of a drug and the potential for interaction with other drugs the patient is taking.  The patient should also be told if alternative treatments are available.  The patient should also be strongly encouraged to read the package insert and to call the physician or pharmacist with any questions.  Finally, the patient should be advised to seek medical attention if serious side effects occur. In short, the patient must make a knowing, voluntary and competent decision regarding his medical care, and this includes the decision to accept or decline a medication. 


The question may be asked did the physician provide enough information based on the standard of care and was it conveyed to the lay person in a manner in which the lay person would understand it.  The prescribing physician is generally guided to disclose the patient’s diagnosis, the proposed treatment, the consequences of accepting or declining the treatment, and existing alternatives to the treatment proposed.  All discussions should be noted in the patient’s record.


E. Douglas Stephan is a partner with Sturgill, Turner, Barker & Moloney, PLLC.  His practice concentrates in the areas of healthcare and medical malpractice defense.  He can be reached at; (859)255-8581, or visit our website at


This article does not constitute legal advice.