Zestril (lisinopril) is a prescription drug that’s used to treat high blood pressure and certain other conditions. The drug comes as a tablet you swallow. It’s usually taken once per day.

Zestril is used to:

The active ingredient in Zestril is lisinopril. (An active ingredient is what makes a drug work.) Zestril belongs to a group of drugs called angiotensin-converting enzyme (ACE) inhibitors

This article describes the dosages of Zestril, as well as its strengths and how to take it. To learn more about Zestril, see this in-depth article.

This section describes the usual dosages of Zestril. Keep reading to learn more.

What is Zestril’s form?

Zestril is available as a tablet that you swallow.

What strengths does Zestril come in?

Zestril comes in several strengths:

  • 2.5 milligrams (mg)
  • 5 mg
  • 10 mg
  • 20 mg
  • 30 mg
  • 40 mg

What are the usual dosages of Zestril?

Your doctor will likely start you on a low dosage and adjust it over time to reach the right amount for you. They’ll ultimately prescribe the smallest dosage that provides the desired effect. The maximum dose of Zestril depends on the condition the drug is being used to treat.

The information below describes dosages that are commonly used or recommended. But be sure to take the dosage your doctor prescribes for you. They’ll determine the best dosage to fit your needs.

Dosage for high blood pressure

The typical starting dosage of Zestril for high blood pressure in adults is 10 mg taken once per day. Your dose may be adjusted based on how you respond to treatment. The usual dosage range is 20–40 mg taken once per day. The maximum dosage of Zestril is 80 mg taken once per day.

In some cases, if Zestril alone is not working to manage your blood pressure, your doctor may prescribe Zestril with a diuretic (water pill), such as hydrochlorothiazide (Microzide). In this case, the starting dosage of Zestril is usually 5 mg taken once per day.

Your doctor will adjust your dose of Zestril or the diuretic medication to reach the right amount that provides the desired effect to manage your high blood pressure.

Dosage for heart failure

Zestril is typically used as an add-on treatment with certain other medications in adults with heart failure. These other medications include a diuretic and another heart medication, digoxin. The usual starting dosage of Zestril is 5 mg taken once per day.

If someone has hyponatremia (low blood sodium levels), the usual starting dose of Zestril is 2.5 mg taken once per day.

The maximum dose of Zestril for heart failure is 40 mg taken once per day.

Dosage for heart attack

Zestril is used to lower the risk of death in adults who have had a heart attack. The first dose of Zestril is typically 5 mg taken within 24 hours after the first signs of a heart attack. This is followed by another 5-mg dose 24 hours after the first dose, then a 10-mg dose 24 hours after the second dose. After this, you will take 10 mg once per day for at least 6 weeks. You may receive the first doses of Zestril for a heart attack in the hospital.

If you have low blood pressure, your doctor will start you on a low dose of 2.5 mg during the first 3 days after a heart attack.

Your doctor will monitor your blood pressure and adjust your dose based on how you do with Zestril treatment. If your blood pressure becomes too low, they’ll likely stop Zestril and discuss other treatment options that may be more suitable for you.

What’s the dosage of Zestril for children?

Zestril is used to help treat high blood pressure in children ages 6 years and older.

The dosage used in children is based on their body weight.

The starting dosage is typically 0.07 mg per kilogram (kg) of body weight up to a total of 5 mg taken once per day.

One kg equals about 2.2 pounds (lb). For example, if your child weighs 20 kg (44 lb), their starting dosage would be 1.4 mg taken once per day.

Your child’s doctor will adjust the dosage based on how your child responds to Zestril. The dosage may be increased to 0.61 mg/kg or up to a maximum dosage of 40 mg once per day.

For more information about Zestril’s dosage for children, talk with your child’s doctor or a pharmacist.

Is Zestril used long term?

Yes, Zestril is usually used as a long-term treatment. If you and your doctor determine that it’s safe and effective for your condition, you’ll likely take it long term.

Dosage adjustments

In certain cases, you may need dosage adjustments for Zestril.

If you have kidney problems such as severe kidney disease or are undergoing hemodialysis, your doctor may lower your starting dosage of Zestril.

Usually, you’ll start with half of the recommended dosage for the condition the drug is being used to manage. Your doctor will adjust your dosage based on your response to Zestril up to a maximum dosage of 40 mg taken once per day.

If you have questions about dosage adjustments you may need for Zestril, talk with your doctor.

The dosage of Zestril you’re prescribed may depend on several factors. These include:

  • the type and severity of the condition you’re using the drug to treat
  • body weight (in children)
  • race
  • age
  • other medications you may be taking
  • other conditions you may have (see the “Dosage adjustments” section above)

Zestril is available as an oral tablet that you swallow once per day. Try to take it around the same time every day to keep steady levels of the medication in your body to treat your condition. You can take Zestril with or without food.

It is possible to crush or cut Zestril tablets to make it easier for you to swallow the medication.

If you have trouble swallowing tablets, you can also see this article for tips on how to take this form of medication.

For information on the expiration, storage, and disposal of Zestril, talk with your doctor or pharmacist.

Accessible drug containers and labels

Some pharmacies provide medication labels that:

  • have large print
  • use braille
  • feature a code you can scan with a smartphone to change the text to audio

Your doctor or pharmacist may be able to recommend pharmacies that offer these accessibility features if your current pharmacy doesn’t.

Let your pharmacist know if you have trouble opening medication bottles. They may have tips to help, or they may be able to supply Zestril in an easy-open container.

If you miss a dose of Zestril, take it as soon as you remember. But if it’s almost time for your next dose, skip the missed dose and take your next dose at its usual time. Don’t take two doses of Zestril to catch up on a missed dose. This can increase your risk for side effects of the medication.

If you’re not sure whether you should take a missed dose, talk with your doctor or pharmacist.

If you need help remembering to take your dose of Zestril on time, try using a medication reminder. This can include setting an alarm or downloading a reminder app on your phone.

Do not take more Zestril than your doctor prescribes, as this can lead to harmful effects.

What to do in case you take too much Zestril

Call your doctor right away if you think you’ve taken too much Zestril. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 (or your local emergency number) or go to the nearest emergency room.

Below are answers to some commonly asked questions about Zestril’s dosage.

What is considered a high dose of Zestril?

There is no high dose of Zestril. The dosage of Zestril your doctor prescribes depends on the condition the drug is being used to treat and any other medications you may be taking.

Your doctor will typically start you on a low dosage of Zestril and slowly increase your dosage to manage your condition.

The maximum dosage of Zestril depends on the condition the drug is being used to treat. For example, the maximum dose of Zestril for high blood pressure is 80 mg taken once per day, but the maximum dosage for heart failure is 40 mg taken once per day. (To learn more about Zestril’s dosage, see the “What is Zestril’s dosage?” section above.)

If you have questions or concerns about your Zestril dosage, talk with your doctor.

How long does it take for Zestril to start working?

How long it takes Zestril to work depends on your Zestril dosage and the severity of your condition. For example, if you’re taking Zestril for high blood pressure, the medication may start to lower your blood pressure 1–6 hours after you take your first dose. But keep in mind that you may not notice any physical changes as Zestril starts working. Your doctor may adjust your dosage based on how you respond to treatment.

Your doctor will monitor you during treatment with Zestril to check whether the drug is working to treat your condition. They may adjust your dosage based on how you respond to treatment.

If you have other questions about what to expect from your Zestril treatment, talk with your doctor.

The sections above describe the usual dosages provided by the manufacturer. If your doctor recommends Zestril for you, they’ll prescribe the dosage that’s right for you.

Remember, you should not change your dosage of Zestril without your doctor’s recommendation. Only take Zestril exactly as prescribed. Talk with your doctor if you have questions or concerns about your current dosage.

Here are some examples of questions you may want to ask your doctor:

  • Can I remain on the starting dosage of Zestril if it’s managing my blood pressure?
  • Does taking the maximum dose of Zestril increase my risk for side effects?
  • How does the dose of Zestril compare with Altace (ramipril)?

To learn more about Zestril, see this article:

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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.