Medication Errors: What to Do and How to Prevent Them

What to do right now

1. Stay calm and check exactly what was taken: the name, strength, number of pills or amount of liquid, and the time. Keep the bottle or packet.
2. Call 911 if the person is unconscious, has trouble breathing or is having a seizure.
3. Otherwise call Poison Control at 1-800-222-1222 (US). It is free, confidential and staffed by nurses, pharmacists and doctors. Most medicine mistakes can be managed safely at home with their advice. You can also use the webPOISONCONTROL online tool.
4. Do not make the person vomit and do not give anything to "counteract" the medicine unless advised.
5. Do not take the next dose of the same medicine until you have been told whether to skip it.

Types of medication errors

Errors can happen at any stage:

The FDA receives more than 100,000 reports of suspected medication errors each year, and many more go unreported.

Common medication mistakes at home

• Double dosing: forgetting a dose was already taken, or two caregivers each giving the same dose.
• Liquid medicine errors: using kitchen spoons, or confusing teaspoons (tsp), tablespoons (tbsp) and milliliters (mL). This is a leading cause of dosing errors in children.
• Doubling an ingredient: taking a cold remedy and a pain reliever that both contain acetaminophen, or two NSAIDs.
• Mixing up pills: similar-looking tablets, pills moved to unlabeled containers, or taking a spouse's medicine.
• Wrong frequency: most dangerously, taking weekly methotrexate every day, which can be fatal.
• Wrong route or form: swallowing a medicine meant for the skin, eye or ear, or crushing or chewing extended-release tablets, which releases the whole dose at once.
• Insulin errors: confusing long-acting and rapid-acting insulin, or wrong units with a pen or syringe.
• Stopping or restarting medicines after a hospital stay without a clear updated list.

High-alert medications

Some medicines cause serious harm even with small errors. The Institute for Safe Medication Practices calls them high-alert medications:

• Insulin and sulfonylureas: risk of severe hypoglycemia. See insulin overdose.
• Blood thinners such as warfarin, apixaban and heparin: bleeding. See warfarin toxicity.
• Opioids, especially long-acting forms and fentanyl patches: slowed breathing. See opioid overdose.
• Methotrexate: bone marrow suppression, mouth ulcers and organ damage.
• Digoxin, lithium and some heart rhythm and seizure medicines: narrow margin between a helpful and a toxic dose. See drug toxicity.
• Concentrated potassium and some chemotherapy drugs in hospital.

Who is most at risk

• Children: doses depend on weight, and liquid measuring mistakes are easy. Young children may also find and swallow adult medicines.
• Older adults: many take five or more medicines (polypharmacy), may see several prescribers and may have memory or vision problems.
• People moving between care settings: hospital discharge and transfers are common points for errors.
• People with limited health literacy or language barriers.

Symptoms after a medication error

Symptoms depend on the drug. Many mistakes cause none. Possible signs include:

• drowsiness, confusion or unusual behavior
• dizziness, fainting or a slow, fast or irregular heartbeat
• nausea, vomiting or stomach pain
• slow or shallow breathing
• shakiness, sweating and hunger (low blood sugar)
• unusual bruising or bleeding
• a rash, hives or swelling (an allergic reaction)

Some effects are delayed. Acetaminophen overdose, for example, may cause no symptoms for a day while liver damage develops, which is why prompt advice matters even if the person feels well.

How doctors manage medication errors

Treatment depends on the medicine, amount, timing and the person's health. It may include observation, blood levels of the drug, activated charcoal in selected cases within a short time window, specific antidotes (such as naloxone for opioids, glucose for insulin, vitamin K or reversal agents for blood thinners, and acetylcysteine for acetaminophen), and heart monitoring.

How to prevent medication errors

• Keep an up-to-date list of every medicine, including over-the-counter drugs, vitamins and supplements, with doses and reasons. Carry it and share it at every visit.
• Use one pharmacy so interactions are checked.
• Ask questions: what it is for, how much, how often, for how long, what to avoid and what side effects to watch for.
• Read the label every time, and check that refills look the same. Ask if they do not.
• Use the dosing device that comes with liquid medicines, preferably an oral syringe marked in mL.
• Check active ingredients on over-the-counter products to avoid doubling up.
• Use a pill organizer or a phone reminder, and a shared log when several people give a child medicine.
• Store medicines up and away in original, child-resistant containers.
• Do a "brown bag" review: bring all your medicines to your doctor or pharmacist once a year.
• Report errors to your pharmacy or provider, and to the FDA MedWatch program or the ISMP reporting program. Reports help prevent the same mistake happening to others.

Frequently asked questions

What should I do if I accidentally took a double dose of my medication?

Call Poison Control at 1-800-222-1222 or your pharmacist with the medicine name, strength and time. For many everyday medicines a single extra dose causes no harm, but for insulin, blood thinners, opioids, heart medicines and some others it can. Skip or delay the next dose only if advised.

What are the most common medication errors?

Common errors include wrong doses, especially with children's liquid medicines, taking a dose twice, mixing up similar pills or names, taking two products with the same ingredient, wrong timing such as daily instead of weekly methotrexate, and omissions or duplicates after hospital discharge.

What happens if you take the wrong medication by mistake?

Often nothing serious happens, especially with a single dose of a low-risk medicine. Some medicines, such as blood pressure, diabetes, heart rhythm and opioid drugs, can cause dangerous effects even after one dose. Call Poison Control for advice specific to the medicine and the person who took it.

I gave my child the wrong dose of medicine. What should I do?

Call Poison Control at 1-800-222-1222 with your child's weight, the medicine and the amount given. Most extra doses of common children's medicines are not dangerous, but the specialists will tell you whether to watch at home or seek care. Call 911 if your child is very drowsy, has trouble breathing or has a seizure.

How do I report a medication error?

Tell the pharmacist, doctor or hospital involved so they can review it. You can also report to the FDA MedWatch program online or by phone, or to the Institute for Safe Medication Practices reporting program. Reports are used to change labels, packaging and safety practices.