Diastat (dye-ah-stat) is the brand name used in the United States and Canada for the seizure medicine with the generic name diazepam in the form of a gel that is inserted into the patient's rectum to stop a cluster of repeated seizures. Similar products are available in the UK and elsewhere.

Diazepam was first used in the United States in 1968. The pill form (best known by the brand name Valium, but also available in many generic forms) is too slowly absorbed when taken by mouth to be used to stop a seizure, and is only moderately effective against epilepsy. If diazepam pills are used daily, they become less effective as tolerance develops, and dependence also becomes a problem. Emergency personnel sometimes give diazepam by injection to stop prolonged or repeated seizures. Diastat, the first at-home alternative, was approved by the United States Food and Drug Administration (FDA) in 1997.


Diastat (DYE-ah-stat) is the brand name used in the United States and Canada for the seizure medicine with the generic name diazepam (dye-az-eh-pam). It is available in a gel form that is inserted into the patient’s rectum to stop a cluster of repeated seizures. Similar products are available in the UK and other countries. It was approved by the United States Food and Drug Administration (FDA) in 1997 as the first at-home alternative to treat clusters of seizures.

Liquid Injection
Diastat Rectal Delivery System

"Quick-Dose" rectal delivery system (resembling a syringe with a flexible, molded tip):

  • Pediatric: 2.5 mg, 5 mg
  • "Universal": 10 mg
  • Adult: 15 mg, 20 mg
2mg diazepam

2mg diazepam

2mg diazepam

2mg diazepam

2mg diazepam

2mg diazepam

5mg diazepam

5mg diazepam

5mg diazepam

5mg diazepam

10mg diazepam

10mg diazepam

10mg diazepam

10mg diazepam

10mg diazepam

10mg diazepam

2mg valium

2mg valium

5mg valium

5mg valium

10mg valium

10mg valium


Diastat is a gel formulation of diazepam intended for rectal administration in the management of selected patients with refractory epilepsy, on stable regimens of antiepileptic drugs, who require intermittent use of diazepam to control bouts of increased seizure activity.

Bouts of increased seizure activity are often called seizure clusters.


Diastat is distributed in the United States by Valeant. The name or appearance may differ in other places. The dose will usually be the same. These descriptions apply to the U.S. versions:

How to take and store Diazepam?

When they filled their prescription, patients or their caregivers should have received written instructions with pictures showing how to give Diastat. Caregivers should be encouraged to study these instructions carefully right away, so they are not trying to learn the steps during a medical emergency. They should understand the procedure and be comfortable with their role in administering the Diastat.

It is also important for the physician to explicitly state in writing the circumstances under which Diastat should be given to a particular patient, and to give these written instructions to all caregivers who may be administering Diastat to that patient. The instructions should also include what caregivers should look for after Diastat has been given and what to do if the patient condition does not improve as expected.

As shown above, Diastat is packaged in plastic applicators of various sizes, which contain different doses of diazepam. Each "Twin Pack" package contains devices for giving the medication two times. Diastat should be stored at room temperature and has a shelf life up to 3 years.

Missed Doses

In general, tell patients that if they forget a dose, they should take it as soon as they remember. If it is almost time for the next dose, they should delay that dose for a few hours instead of taking two doses very close together.

Patients who often forget doses may benefit from using a special pillbox or watch with an alarm.

Mechanisms of actions of Diazepam

Although the precise mechanism of action of diazepam is unknown, it appears to suppress seizures through enhancement of the actions of gamma-aminobutyric acid, the major inhibitory neurotransmitter in the central nervous system.

Please see package insert.

Clinical Pharmacology of Diazepam

Diastat is well absorbed following rectal administration and reaches peak plasma concentrations in 1.5 hours. The half-life in adults is approximately 46 hours. Diazepam and its major active metabolite desmethyldiazepam are over 95% protein-bound.

Diazepam is metabolized in the liver by the CYP3A4 and CYP2C19 isoenzymes to one major active metabolite (desmethyldiazepam) and two minor active metabolites.

Efficacy of Diazepam

Two randomized, double-blind studies compared Diastat to placebo. The first study enrolled 91 patients (47 children, 44 adults), who received the first dose of Diastat at the onset of an identified seizure episode. Children were given a second dose four hours later whereas adults were dosed four and 12 hours after the first dose. The median seizure frequency for the Diastat treated group was zero seizures per hour, compared to a median seizure frequency of 0.3 seizures per hour for the placebo group (p < 0.0001). In addition, 62% of patients treated with Diastat were seizure-free during the observation period (12 hours for children, 24 hours for adults) compared to 20% of placebo patients.

The second study enrolled 114 patients (53 children, 61 adults). The dose was given at the onset of the identified episode. The median seizure frequency for the Diastat-treated group was zero seizures per 12 hours, compared to 2.0 seizures per 12 hours for the placebo group (p < 0.03). Patients treated with Diastat also had prolonged time-to-next-seizure compared to placebo (p = 0.0072).

Common side effects of Diazepam

In clinical trials, the most frequent adverse event reported was somnolence (23%). Less frequent adverse events reported were dizziness, headache, pain, abdominal pain, nervousness, vasodilation, diarrhea, ataxia, euphoria, incoordination, asthma, rhinitis, and rash (2% - 5%).

Serious Side effects of Diazepam

Serious problems are rare. Respiratory suppression is possible if more than one dose is given, especially if the first dose was near the upper limit of what the patient can tolerate. Caregivers should be alert for signs of problems with breathing (including a marked decrease in the rate of breathing or a change in the color of the skin) and should summon help if necessary. If the seizure has stopped but no breathing can be seen for more than 8 to 10 seconds, they should call emergency medical personnel.

Caution is warranted when prescribing Diastat to seniors or patients with liver or kidney dysfunction, because their clearance of Diastat is reduced. Diastat should also be used with caution in patients with respiratory diseases, such as asthma.

Following a dosage of Diastat, patients should avoid activities that require coordination or sustained vigilance until they feel alert.

On July 10, 2008, an advisory panel was convened by the Food and Drug Administration (FDA) to review data that the FDA had previously collected from drug studies showing an association between many of the antiepileptic drugs (AEDs) and suicidal ideation and behavior, which together are called suicidality. According to the FDA’s Alert, among the patients with epilepsy in these drug studies, 1 out of 1000 people taking the placebo (inactive substance) showed suicidality compared to approximately 3.5 out of 1000 people who took an AED. The FDA advisory panel voted to accept the FDA's data at its meeting on July 10.

Taking antiepileptic medicines may increase the risk of having suicidal thoughts or actions;

  • Do not make any changes to the medication regimen without first talking with the responsible healthcare professional;
  • Pay close attention to any day-to-day changes in mood, behavior and actions. These changes can happen very quickly so it is important to be mindful of any sudden differences.

Be aware of common warning signs that might be a signal for risk of suicide. Some of these are:

  •  Talking or thinking about wanting to hurt yourself or end your life
  •  Withdrawing from friends and family
  •  Becoming depressed or having your depression get worse
  •  Becoming preoccupied with death and dying
  •  Giving away prized possessions

We again urge patients and families to contact their doctor before stopping an epilepsy medication because this may possibly lead to seizures and worsening of mood.

Impact of Diazepam on bone health

Please see package insert. 

Other Uses of Diazepam

Some physicians have recommended the use of Diastat in children with a history of febrile seizures in the event they develop a high fever in order to prophylax against febrile seizures.

Diazepam Contraindications

Diastat is contraindicated in patients with a known hypersensitivity to diazepam and in patients with acute narrow angle glaucoma.

Diazepam Interactions with other medications

See package insert.

Diazepam effects on Children

Read package insert.

Diazepam and Pregnancy

Read package insert.

Diazepam effects on Seniors

Read package insert.

Diazepam Dosing and titration

The following information is adapted from the package insert for Diastat.

Calculating Prescribed Dose

The Diastat dose should be individualized for maximum beneficial effect. The recommended dose of Diastat is 0.2-0.5 mg/kg depending on age.

Age (years) Recommended Dose
2 through 5: 0.5 mg/kg
6 through 11: 0.3 mg/kg
12 and older: 0.2 mg/kg

Because Diastat is provided in fixed, unit-doses of 5, 10, 15 and 20 mg, the prescribed dose is obtained by rounding upward to the next available dose. The following table provides acceptable weight ranges for each dose and age category, such that patients will receive between 90% and 180% of the calculated recommended dose. The safety of this strategy has been established in clinical trials.

The rectal delivery system includes a plastic applicator with a flexible, molded tip available in two lengths, designated for convenience as “Pediatric”, “Universal” and “Adult”. The 2.5 and 5 mg dosages are available with a 4.4 cm Pediatric tip, the 10 mg dosage is available with a 4.4 cm Universal tip and the 15 and 20 mg dosages are available with a 6.0 cm Adult tip. It is important to note that if a 15 mg dose is to be administered to a pediatric patient utilizing the plastic applicator with a pediatric tip, prescriptions must be written for 2 different twin packs, one for the 5 mg dosage and one for the 10 mg dosage.

The prescribed dose of Diastat should be adjusted by the physician periodically to reflect changes in the patient’s age or weight. It is recommended that dosage be reviewed at six month intervals.

A 2.5 mg dose is available for use as a supplemental dose. This dose may be prescribed at the discretion of the physician for patients who require more precise dose titration than is achieved using one of the four standard doses provided. The 2.5 mg dose may also be used as a partial replacement dose for patients who may expel a portion of the first dose.

Additional Dose

The prescriber may wish to prescribe a second dose of Diastat. A second dose, when required, may be given 4-12 hours after the first dose.

Treatment Frequency

It is recommended that Diastat be used to treat no more than five episodes per month and no more than one episode every five days.

Diazepam Package insert

In the United States, companies that manufacture medicines are required to publish certain kinds of information about each product. This document is commonly known as a “package insert” because it is usually included with each package of the medicine.

You can also read these documents (also called "prescribing information") online. The U.S. package insert for Diastat (diazepam) is found at:

Some of the information may differ in other countries.

To learn how to read and understand a package insert, see "How to read a package insert."

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