Diastat (diazepam) is a prescription drug used to treat sudden seizure episodes in people with epilepsy. Diastat can cause side effects that range from mild to serious. Examples include sleepiness, dizziness, and headache.

Diastat is prescribed for adults and children ages 2 years and older with epilepsy. Specifically, it’s used to treat sudden and repetitive seizure episodes, also known as seizure clusters or acute repetitive seizures.

The active ingredient in Diastat is diazepam. An active ingredient is what makes a drug work. The drug comes as both Diastat and Diastat AcuDial which are prefilled syringes containing a rectal gel. Diastat AcuDial has a dose display window that Diastat does not.

Keep reading to learn about the common, mild, and serious side effects that Diastat can cause. For a general overview of the drug, including details about its uses, see this article.

Some people may experience mild to serious side effects during Diastat treatment. Examples of the drug’s commonly reported side effects include:

Mild side effects have been reported with Diastat. These include:

  • fatigue (low energy)
  • sleepiness
  • low blood pressure
  • dizziness
  • headache
  • runny nose, congestion
  • diarrhea
  • abdominal pain
  • unsteady or uncoordinated movements
  • euphoria (a state of extreme happiness or excitement)
  • nervousness
  • skin rash
  • mild allergic reaction*†

In most cases, these side effects should be temporary and go away within 6–8 hours. And some may be easily managed until Diastat is cleared from your body. But if you have symptoms that are ongoing or bothersome, talk with your doctor or pharmacist. And do not stop using Diastat unless your doctor recommends it.

Diastat may cause mild side effects other than those listed above. See the drug’s prescribing information for details.

* To learn more about this side effect, see the “Side effects explained” section below.
† An allergic reaction is possible after using Diastat, but this side effect wasn’t reported in studies.

Serious side effects have been reported with Diastat. These include:

If you develop serious side effects while taking Diastat, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

* To learn more about this side effect, see the “Side effects explained” section below.
† To learn more about this side effect, see the “Diastat and misuse” section below.
‡ An allergic reaction is possible after using Diastat, but this side effect wasn’t reported in studies.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Diastat, visit MedWatch.

Diastat is used to help treat sudden seizure episodes in children ages 2 years and older. During drug studies, the side effects reported in children were the same as in adults.

For more information about potential side effects of Diastat in children, talk with your doctor or pharmacist.

Get answers to some frequently asked questions about Diastat’s side effects.

Does Diastat AcuDial have the same side effects as Diastat?

Diastat and Diastat AcuDial both contain the same active ingredient diazepam. While both are applied as a rectal gel, Diastat AcuDial features a user-friendly system that lets the pharmacist set and lock a specific patient dose.

Because they both have the same ingredients, the side effects are the same for both versions of the drug.

How long should I monitor someone for side effects after giving them a Diastat dose?

The Epilepsy Foundation recommends monitoring the person for 4 hours after administering a dose of Diastat. Side effects to look for include paleness, shallow breathing, difficulty waking up, and severe confusion. Call 911 or your local emergency number right away if these side effects occur. These symptoms could be life threatening and require immediate medical care.

Talk with your doctor to learn more about possible side effects of Diastat and how long they may last.

Learn more about some of the side effects Diastat may cause.

Risk of serious harm if taken with opioids

Serious harm when taken with opioids was a common side effect reported in studies of benzodiazepines (the group of drugs Diastat belongs to). Using Diastat while taking opioids may cause:

  • heavy, drug-induced sleep
  • the inability to breathe
  • coma
  • death

As the dose of Diastat or the opioid increases, the risk of serious harm increases. Examples of opioids include:

What might help

You should only take these drugs together when recommended by a doctor and when other treatment options don’t work well enough. Ask your doctor to keep the dosage amount and time using them as low and short as possible. Always follow professional medical advice for specific dosage and duration instructions.

Risk of withdrawal and dependence

Studies show that using a Schedule IV controlled substance, such as Diastat (a benzodiazepine), for too long can cause physical dependence. This is when your body gets used to a drug and needs it for you to function as usual. Suddenly stopping Diastat can cause withdrawal symptoms if you’ve been using it often. Symptoms of withdrawal include:

You may use Diastat for up to five seizure episodes per month but not more than once every 5 days. If you’ve been using more than that, you may need to decrease the amount you use over time. If you’ve been using Diastat more than prescribed, contact your doctor right away so they can give you instructions for safely decreasing your usage.

What might help

Consider keeping a calendar or chart tracking your doses and dates of Diastat use. This will help you see whether you’re reaching the prescribed limits. Contact your doctor right away if your seizures are becoming more frequent or lasting longer.

Allergic reaction

Like most drugs, Diastat can cause an allergic reaction in some people. But this side effect wasn’t reported in studies. Symptoms can be mild to serious and can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin (usually in your eyelids, lips, hands, or feet)
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms. Examples include:

  • an oral antihistamine, such as Benadryl (diphenhydramine)
  • a product you apply to your skin, such as hydrocortisone cream

If your doctor confirms you’ve had a mild allergic reaction to Diastat, they’ll decide if you should continue using it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Diastat, they may have you switch to a different treatment.

Keeping track of side effects

During your Diastat treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start taking a new drug or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of the drug you were taking when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how your symptoms affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help them learn more about how Diastat affects you. They can then use this information to adjust your treatment plan if needed.

Below is important information you should consider before starting Diastat.

Boxed warnings

Diastat has boxed warnings about the risk of withdrawal and dependence, misuse and addiction, and serious harm if taken with opioids. Boxed warnings are the most serious warnings from the Food and Drug Administration (FDA).

Risk of withdrawal and dependence.* People who use Diastat frequently or for a long time may have physical dependence or withdrawal symptoms if they stop using it quickly. Withdrawal symptoms are side effects caused by suddenly stopping a drug. These reactions can be life threatening and require emergency medical care. If you’ve been using Diastat more than recommended, you’ll need to follow a specific plan made for you by your doctor. They’ll have you slowly reduce your usage of the drug over time.

Risk of misuse and addiction.† Diastat use may lead to misuse and addiction. This often involves using too much Diastat, sometimes with other drugs, alcohol, or illegal substances. Using these substances together increases the risk of serious problems such as trouble breathing, overdose, or death.

Risk of serious harm if taken with opioids.* Using Diastat together with opioids can cause extreme sleepiness, breathing problems, coma, and even death. Doctors should only prescribe these drugs together if the patient has no other safe treatment options.

* To learn more about this side effect, see the “Side effects explained” section above.
† To learn more about this side effect, see the “Diastat and misuse” section below.

Other warnings

Diastat can sometimes cause harmful effects in people with certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether Diastat is a good treatment option for you. Talk with your doctor about your health history before starting Diastat. Be sure to tell them if any of the following factors apply to you:

Alcohol and Diastat

You should not use Diastat when consuming alcohol. When the two substances are used at the same time, it increases the risk of severely slowing your brain and nervous system. This can lead to symptoms such as:

  • heavy, drug-induced sleep
  • the inability to breathe

It can also lead to coma and death.

If you have questions about consuming alcohol while using Diastat, talk with your doctor or pharmacist.

Pregnancy and breastfeeding with Diastat

Diastat is usually only prescribed for someone who’s pregnant or breastfeeding if the benefits of treatment outweigh the potential risks to the fetus or breastfeeding child.

Pregnancy

Diastat may not be safe for a fetus. If you’re pregnant or planning to become pregnant, talk with your doctor about your treatment options.

Using Diastat late in pregnancy may make the newborn sleepy or cause them to have breathing issues. It could also cause withdrawal symptoms such as being overly fussy, shaking, crying continuously, and having trouble eating.

If you’re able to become pregnant, your doctor may recommend using an effective form of birth control during your Diastat treatment.

If you use Diastat while pregnant, consider signing up for the North American Antiepileptic Drug Pregnancy Registry by visiting the website or calling 888-233-2334. A pregnancy registry collects information about the safety of certain drugs when used during pregnancy.

Breastfeeding

Diastat may not be safe to use while breastfeeding. This drug passes into breast milk and may cause side effects in a child who’s breastfed. These side effects may include:

  • excessive sleepiness
  • not eating well
  • not gaining weight

If you notice these side effects call your doctor or your child’s pediatrician right away.

To avoid breastfeeding with breastmilk containing Diastat, you may consider pumping and discarding milk as directed by your physician. Replace feedings during this time with doctor-recommended formula or pre-pumped milk.

If your child has difficulty breathing or problems waking up after taking breastmilk containing Diastat, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If you’re breastfeeding or planning to do so, talk with your doctor about your treatment options.

Diastat has a boxed warning for the risk of misuse and addiction. With misuse, a drug is taken in a way or for a reason other than how it was prescribed. Addiction is when a drug is taken even if it’s causing harmful effects.

Diastat is a Schedule IV controlled substance that has a moderate risk of misuse during treatment. Examples of misuse include using the drug more often or at higher doses than your doctor recommends.

Be sure to discuss current or past alcohol or drug misuse with your doctor before starting Diastat.

You should use this drug only as prescribed by your doctor. Misuse increases the risk of overdose, which can lead to trouble breathing, coma, and even death.

Like most drugs, Diastat can cause several side effects ranging from mild to serious. But most are temporary and go away after a few days to weeks. If you have questions about side effects this drug can cause, talk with your doctor. Examples of questions to help get you started include:

  • Based on my health history, are there certain side effects I might be likely to have from Diastat?
  • When using this medication, what symptoms should prompt me to get immediate medical help?
  • How might Diastat affect my mood, alertness, or mental state?

To learn more about Diastat, see these articles:

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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.