Lisinopril Overdose and Accidental Excess Dose: Recognition, Risks, and Emergency Management

If you took more lisinopril than prescribed, call U.S. Poison Control at 1-800-222-1222 for instructions based on the amount, timing, symptoms, and your other medicines. Call 911 immediately if the person collapses, has a seizure, has trouble breathing, or cannot be awakened. Do not wait for a blood-pressure reading before getting help for those symptoms. [1,2]

An accidental extra tablet and a large ingestion require different assessments. The number printed on a usual-dose chart cannot tell you whether an overdose is safe to manage at home.

What to do after an accidental extra dose

Have the medication package available when you call. Report:

• The tablet strength and the number that may have been taken.
• The time of the usual dose and the extra dose.
• The person's age, approximate weight, and current symptoms.
• Other medicines taken, including combination blood-pressure tablets.
• Known kidney problems and any recent vomiting, diarrhea, or poor fluid intake.

Poison Control can help determine whether home observation or medical evaluation is appropriate. Do not induce vomiting. Ask specifically when the next prescribed dose should be taken; there is no single restart instruction for every dosing error. [1,2]

If you are told to go to an emergency department, bring the package and remaining medicines. Do not drive yourself if you feel dizzy or unwell. [3]

Is 80 mg the threshold for an overdose?

No. Lisinopril labeling describes a usual adult hypertension range of 20 to 40 mg daily and notes that doses up to 80 mg have been used without appearing to add greater effect. That statement is about treatment dosing. It does not establish 80 mg as a poisoning threshold or make every amount below it safe. [4]

The relevant question is how much was taken compared with the prescription, together with symptoms, kidney function, other medicines, and the time since ingestion. Do not use another person's prescribed dose to decide what is safe for you.

What symptoms can occur?

Excess lisinopril can lower blood pressure too far, causing dizziness, weakness, fainting, or collapse. Kidney problems can also occur. A person who feels well immediately after taking an extra dose can still need assessment. [1]

In a hospital study of 33 ACE-inhibitor overdoses, the median time to the lowest recorded systolic blood pressure was 4.5 hours. Heart rate did not rise substantially in response. A normal pulse therefore does not settle whether blood pressure is affected. This hospital observation study is not a home waiting-period rule. [5]

Why kidney function and other medicines matter

Lisinopril is eliminated through the kidneys. Its label describes increased exposure when kidney function is substantially reduced. Diuretics, other blood-pressure medicines, potassium-raising medicines, and NSAIDs can change the clinical assessment. [4]

Report the complete medication list rather than deciding which medicines seem relevant. If the tablet contains lisinopril plus hydrochlorothiazide, tell the poison specialist both ingredients and their strengths.

What emergency treatment involves

The main treatment goal is to support blood pressure and identify complications. Lisinopril labeling describes intravenous normal saline for overdose-related hypotension and notes that hemodialysis can remove the drug. [4]

Hospital assessment may include repeated blood-pressure measurements, an ECG, and blood tests for kidney function and electrolytes. Treatment and observation depend on the findings and any other substances taken. The published ACE-inhibitor overdose series included patients who needed intravenous fluids and, in one case, blood-pressure support with norepinephrine. [5]

Treatment should not be delayed while trying to calculate a supposedly safe dose from an online table.

Children and intentional ingestion

Call Poison Control promptly if a child may have swallowed lisinopril, even if the amount is uncertain or the child looks well. Use 911 for the emergency symptoms described above. Do not wait until you know whether more than one tablet is missing. [1,2]

For an intentional ingestion or immediate danger of self-harm, seek emergency help. Tell responders about all medicines that may have been taken, including uncertain amounts.

Preventing another dosing error

After the immediate situation is resolved, choose one way to record each dose: a dated medication log, a reminder marked completed after taking it, or an appropriate pill organizer. If someone helps with medicines, agree who records the dose so that two people do not give it separately. Keep medicines out of children's reach. [6]

Frequently asked questions

I took two tablets but feel fine. Should I skip tomorrow's dose?

Call Poison Control or the prescribing team for the next-dose instruction. The tablet strength, timing, symptoms, and health history matter. A universal instruction to skip one day can be wrong for a particular situation.

Does a normal blood-pressure reading mean I am in the clear?

One reading does not replace an assessment of the exposure. Follow the observation instructions you receive and report symptoms that develop afterward. [5]

Should I make myself vomit?

No. Do not induce vomiting after a suspected poisoning. [2]

References

1. National Capital Poison Center. Lisinopril and excess dosing.
2. National Capital Poison Center. First aid for poisonings.
3. NHS. Lisinopril: taking too much and seeking care.
4. DailyMed. Lisinopril prescribing information.
5. Lucas C et al. Rapid onset of haemodynamic effects after ACE-inhibitor overdose. Emergency Medicine Journal, 2006.
6. National Capital Poison Center. Medication errors and double dosing.