A study conducted by the Institute for Safe Medication Practices (ISMP) found that this error happens about once for every 1,000 prescriptions filled.1 With close to 4 billion prescriptions filled each year, an average of 7 errors happen each month at every pharmacy across the US.
Most people trust that the pharmacist will fill their prescriptions accurately. In fact, Americans have rated pharmacists as one of the most trusted professions for years. Yes, pharmacists deserve the trust we've placed in them. But they are human and could make a mistake, as could the person who rings up the sale.
How errors happen
Giving a correctly filled prescription to the wrong customer can happen for several reasons. First, a mistake can be made when placing the filled prescription in a bag for pick-up. These errors often stem from working on more than one patient's prescription at a time, and then placing the medicine in the wrong bag. Most people pick up their medicine and leave the pharmacy without ever opening the bag. Furthermore, many pharmacies do not require their workers to open the bag prior to ringing up the sale. So, they do not look at each filled prescription in the bag when giving it to the patient to be sure it is for the correct person. People may notice the error once they get home, especially if the medicine looks different than expected. But a government study shows that only about half of patients confirm their name on the prescription label, and only about three-quarters confirm the medicine's name prior to taking the medicine.2 As a result, many people have taken the wrong patient's medicine.
Another way a correctly filled prescription can be given to the wrong customer is when pharmacy workers select the wrong bag of medicines for customers. The process of identifying the customer can be incorrect if both a full name and birthdate are not asked for and provided at the time of sale. Some pharmacy workers believe they know their customers by sight and have not developed the safe habit of always asking customers to state their full name and birthdate. Or, caregivers, friends, and even family members who pick up prescriptions for the patient may not know the patient's birthdate. Thus, the wrong customer's bag may be chosen if there are medicines in the pick-up area for customers with the same or a similar last name. Using an address to identify customers is not ideal, as people with the same last name often live together.
Consequences of errors
There are numerous ways that people can be harmed from this type of error.
Taking a contraindicated medicine. If you do not notice the error and take another patient's medicine, it could be a medicine that should never be taken given your current health condition, other medicines you are taking, or allergies. For example, a pregnant woman who intended to fill a prescription for an antibiotic to treat an infection was accidentally given another woman's prescription for methotrexate instead. Both women had the same last name and very similar first names. The pregnant woman took one tablet of methotrexate before noticing the error. Methotrexate is a medicine used to treat certain cancers or other conditions such as rheumatoid arthritis and psoriasis. The medicine prevents cell growth and should never be taken by a pregnant woman. It can cause birth defects in the brain, bone, and heart, or cause a miscarriage. The pregnant woman was seen in the emergency department, but it was too early to determine if the unborn child had been harmed.
Omission of the correct medicine. Another problem with receiving and taking the wrong patient's medicine is that you may not be taking the correct medicine prescribed for you. This can lead to untreated health conditions that can worsen over time or cause other adverse effects on your health. For example, a patient who had been prescribed an antibiotic for a serious bacterial infection accidentally received another patient's medicine, sertraline (Zoloft), to treat depression, instead. After 10 days, the patient became very ill as the infection raged on untreated. Another patient had been prescribed a pain reliever but instead received another patient's filled prescription for allopurinol, a gout medicine. After days of pain without relief, she noticed the error and called the pharmacy to correct the mistake.
Misuse of the wrong medicine. Customers who are accidentally given the wrong patient's medicines have occasionally misused these medicines for recreational purposes or to harm themselves. In one case, a customer went to the pharmacy to pick up prescriptions for an allergy medicine and oxycodone, a narcotic pain reliever. The pharmacy found that the filled prescriptions had accidentally been given to another customer. When this customer was called, he denied receiving the wrong prescription, presumably because of the oxycodone—a common drug of abuse. In another case, a woman who had picked up a prescription filled for Premarin (estrogen) found another patient's medicine also in the bag when she arrived home. The medicine was amitriptyline (Elavil), a medicine to treat depression. Later, a pharmacist received a call from a local hospital to tell her the woman was in the emergency department after taking 30 amitriptyline tablets filled by the pharmacy for another patient, in what appeared to be a suicide attempt.
Violation of protected health information. Another unfortunate aspect of this type of error is that confidential information is shared with the person who receives another person's medicine. The full name and address of the patient, along with the drug name, are on the pharmacy label. For sensitive medicines, such as psychiatric medicines or medicines that treat human immunodeficiency syndrome (HIV), patients may be deeply troubled that another person is aware of this information.
How to prevent harm
There are several steps people can take to detect this type of error and avoid potential harm from taking the wrong medicine or not taking the correct medicine. First, check the filled prescriptions your pharmacist has given you before you leave the pharmacy. Open the bag at the counter to view the medicine labels to be sure the medicine is for you and looks correct. This simple step can cut the risk in half of taking home the wrong patient's medicine.
Another strategy is to always provide the pharmacy with your full name and birthdate when picking up prescriptions. This is important even if you know your pharmacy workers well, and they know you. This step reduces the risk of taking home the wrong patient's medicine by one-third.1 Talking to the pharmacist about your prescription medicines before you leave the pharmacy also reduces the risk of taking home the wrong medicine by another quarter. Providing your full name and birthdate, opening the bag to view each medicine bottle, and talking to your pharmacist about your medicine can help eliminate the risk of going home with the wrong medicine.
Every time you pick up a filled prescription, whether it is new or a refill, do these things before you leave the pharmacy:
Open the bag. Take the filled prescription out of the bag to view the label. Are your name and your doctor's name correct? Do not assume that any errors are just typing mistakes. A misspelled name could mean you have someone else's prescription medicine.
Read the label. Read the drug name and directions on the label. Make sure it is what your doctor told you, and that you understand how much medicine to take and how many times a day you should take it. See page 4 for tips on how to read a pharmacy label to verify that you have received the correct medicine and know how to take it correctly.
Check the reason. Open the patient information leaflet provided. Read the name of the medicine and what condition the medicine is supposed to treat. This information is usually found at the top of the page. Is the medicine what you expected? Does it treat your condition? If not, it could signal an error, so check with your pharmacist. (Read the full information leaflet once you are home and call the pharmacist if you still have questions.)
Check the appearance of the medicine. If you are getting a refill, open the bottle to make sure the medicine looks the same as it did last time. If it looks different, ask the pharmacist about it. Most likely, the pharmacist has filled your prescription with a generic drug that looks different from what you're used to. But mistakes are possible, so check with the pharmacist to be sure.
Talk to a pharmacist. When picking up a new prescription, ask the pharmacist at least one question about it. Here are some examples:
Is there anything special I should know about taking this medicine?
Does the information sheet you gave me cover everything I should know?
I'm allergic to ______. Should I still take this medicine?
I'm also taking ______, which I got at another pharmacy. Can I take both safely?
1. Cohen MR, Smetzer JL, Westphal JE, Conrow Comden S, Horn DM. Risk models to improve safety of dispensing high-alert medications in community pharmacies. J Am Pharm Assoc. 2012;52(5):584-602.
2. Trettin KW, Narus E. Implementation of a VA patient-centered prescription label. Chapter 47. In: Advances in Human Aspects of Healthcare, ed. Duffy VG, 2012. Boca Raton, FL: CRC Press; p. 429-38.