pentobarbital
Pentobarbital (also known by its brand name Nembutal) is a medication belonging to the barbiturate drug class. It's given by injection in the hospital to help people relax and to control seizures in certain emergency situations. Pentobarbital (Nembutal) a schedule II controlled substance because of its risk of being habit-forming and causing dependence. The most common side effect is sleepiness.
What is Pentobarbital (Nembutal)?
What is Pentobarbital (Nembutal) used for?
How Pentobarbital (Nembutal) works
Pentobarbital (Nembutal) is a barbiturate. It works by slowing down your brain activity. This is thought to help relax your body and treat seizures.
Drug Facts
What are the risks and warnings for Pentobarbital (Nembutal)?
Pentobarbital (Nembutal) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Habit-forming
Pentobarbital (Nembutal) is a schedule II controlled medication because it has a risk of dependence and tolerance. Dependence can occur when you take a medication for a certain period of time and you start to rely on it to function normally. Over time, you might need greater amounts or higher strengths of the medication to get the effect you need to treat your condition.
With dependence, you can experience bothersome withdrawal symptoms if you stop taking the medication suddenly. These symptoms include anxiety, muscle twitching, weakness, dizziness, changes in vision, nausea, vomiting, trouble sleeping, and seizures. Your provider will monitor your dose and slowly lower it before completely stopping the medication, if needed. Since pentobarbital (Nembutal) is given in the hospital, your provider will check on you often to help make sure the risk that the medication becomes habit-forming is low.
Breathing problems and low blood pressure
Giving pentobarbital (Nembutal) too fast into the vein can cause serious side effects, such as low blood pressure and slowed breathing. Your providers will give you the medication at a speed that's safe for you. They'll monitor you while you're receiving the medication to make sure you aren't having any serious side effects. Your providers will help you right away if they see you're having trouble breathing while you're receiving pentobarbital (Nembutal).
Paradoxical (opposite) reactions
Risk factors: Older adults | Very weak people | Having sudden pain | Long-term pain
In certain people, pentobarbital (Nembutal) can cause paradoxical reactions (opposite effects from what you'd expect). This medication can sometimes cause people to feel distressed, excited, or confused rather than sleepy or calm. This can happen in older adults, very weak people, or people with short- or long-term pain. Tell your provider if you have short- or long-term pain so they can monitor you more closely.
Harm to unborn babies
Pentobarbital (Nembutal) can cause harm to unborn babies when the medication is given to pregnant women. Newborn babies can experience withdrawal symptoms if their mother received this medication in the third trimester. Your provider should be informed whether you're pregnant before they give you pentobarbital (Nembutal) so they can see whether there are safer alternatives.
Sleepiness and slowed breathing
Risk factors: Taking pentobarbital (Nembutal) with medications that cause sleepiness or slowed breathing | Alcohol use
Pentobarbital (Nembutal) can make you sleepy. The sleepiness can be more intense if you receive pentobarbital (Nembutal) after you've recently drank alcohol or taken other medications that can slow your body down, such as sedatives and opioids. In addition, the combination with alcohol, these medications, and pentobarbital (Nembutal) can lead to slowed breathing, which can be life-threatening. Let your provider know about all of the medications you're taking so they can check for potentially dangerous interactions.
What are the side effects of Pentobarbital (Nembutal)?
Common Side Effects
- Sleepiness
Other Side Effects
- Confusion
- Dizziness
- Headache
- Fever
- Irregular breathing
- Nausea
- Low blood pressure
Serious Side Effects
- Dangerously slow breathing: shortness of breath; bluish-colored lips, fingers, or toes
- Serious allergic reactions: rash, hives, painful blisters
Source: DailyMed
The following side effects have also been reported
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
- CNS depression—slow or shallow breathing, shortness of breath, feeling faint, dizziness, confusion, trouble staying awake
Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):
- Confusion
- Dizziness
- Drowsiness
- Headache
- Nausea
- Vomiting
Pros and cons of Pentobarbital (Nembutal)
Pros
Works well as a sedative, hypnotic (for sleeping), and emergency antiseizure medication
Starts to work almost immediately when it's given through the vein (IV)
Cons
Only available as an injection given in the hospital
Can lead to withdrawal effects if stopped too suddenly
Pharmacist tips for Pentobarbital (Nembutal)
Make sure your healthcare team has a complete and up-to-date list of all the medications you're taking. They'll review your medications to prevent dangerous drug interactions with pentobarbital (Nembutal). Some common medications that interact with pentobarbital (Nembutal) include phenytoin (Dilantin), doxycycline, warfarin (Coumadin), and antihistamines.
Depending on how long you've received pentobarbital (Nembutal) for in the hospital, your provider will slowly lower the dose to avoid withdrawal symptoms like seizures, anxiety, and sleeping problems.
Pentobarbital (Nembutal) can make you sleepy and dizzy, even after you've left the hospital. Avoid drinking alcohol, driving, or doing anything that requires concentration after receiving pentobarbital (Nembutal) until you know how this medication affects you and you feel its effects are wearing off.
Frequently asked questions about Pentobarbital (Nembutal)
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Pentobarbital (Nembutal) dosage forms
Typical dosing for Pentobarbital (Nembutal)
Injection into the muscle (intramuscular, IM)
Adults: The typical dose is 150 mg to 200 mg as a single dose.
Children: The dose will depend on your child's body weight. The typical dose is 2 mg/kg to 6 mg/kg of weight (up to 100 mg) as a single dose.
Injection into the veins (intravenous, IV)
The typical dose varies from one person to another. It depends on your body weight, your age, your medical conditions, and why you need to receive pentobarbital (Nembutal). Your provider will calculate the right dose to give to you.
Pentobarbital (Nembutal) contraindications
Allergy to barbiturates
History of porphyria (rare medical condition that mainly affects the skin or nervous system)
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References
Best studies we foundAnbalagan, S., et al. (2023). Neonatal abstinence syndrome. StatPearls.
Battaglini, D., et al. (2020). Escalate and de-escalate therapies for intracranial pressure control in traumatic brain injury. Frontiers in Neurology.
Benzoni, T., et al. (2023). Procedural sedation. StatPearls.
BPI Labs LLC. (2023). Phenobarbital sodium injection [package insert]. DailyMed.
Centers for Disease Control and Prevention. (2020). Types of seizures.
Department of Justice/Drug Enforcement Administration. (2020). Narcotics.
Hikma Pharmaceuticals USA Inc. (dba Leucadia Pharmaceuticals). (2023). Pentobarbital sodium- pentobarbital sodium injection, solution [package insert]. DailyMed.
Johnson, A. B., et al. (2022). Pentobarbital. StatPearls.
Kim, D., et al. (2021). Antiepileptic drug therapy for status epilepticus. Journal of Clinical Neurology.
Lee, D.C. (2015). Sedative-hypnotics. Goldfrank's Toxicologic Emergencies, 10e. McGraw-Hill Education.
National Institute of Diabetes and Digestive and Kidney Diseases. (2020). Porphyria.
Pugin, D., et al. (2014). Is pentobarbital safe and efficacious in the treatment of super-refractory status epilepticus: A cohort study. Critical Care.
Smith, S. W., et al. (2012). Paradoxical and bidirectional drug effects. Drug Safety.
Straw, R. N., et al. (1967). A comparison of the effects of phenobarbital and pentobarbital on motor cortical threshold and righting reflex response in the cat. Journal of Pharmacology and Experimental Therapeutics.
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