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Seconal Sodium Side Effects

Generic name: secobarbital

Medically reviewed by Last updated on Sep 4, 2022.

Note: This document contains side effect information about secobarbital. Some dosage forms listed on this page may not apply to the brand name Seconal Sodium.

Applies to secobarbital: oral capsule.

Serious side effects of Seconal Sodium

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • New or worse behavior or mood changes like depression or thoughts of suicide.
  • Feeling confused.
  • Feeling agitated.
  • Feeling nervous and excitable.
  • Hallucinations (seeing or hearing things that are not there).
  • Memory problems or loss.

Other side effects of Seconal Sodium

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at

For Healthcare Professionals

Applies to secobarbital: injectable solution, oral capsule.

Nervous system

Common (1% to 10%): Somnolence

Frequency not reported: Ataxia, central nervous system (CNS) depression, dizziness, headache, hyperkinesia, syncope[Ref]


Frequency not reported: Abnormal thinking, agitation, anxiety, confusion, dependence, excitement, hallucinations, insomnia, nervousness, nightmares, other complex behaviors, psychiatric disturbance, sleep driving[Ref]


Frequency not reported: Fever, tolerance, withdrawal symptoms[Ref]


Frequency not reported: Constipation, nausea, vomiting[Ref]


Frequency not reported: Apnea, hypoventilation[Ref]


Frequency not reported: Angioedema, hypersensitivity reactions[Ref]


Frequency not reported: Exfoliative dermatitis, skin rashes[Ref]


Frequency not reported: Bradycardia, hypotension[Ref]


Frequency not reported: Megaloblastic anemia[Ref]


Frequency not reported: Liver damage[Ref]


Frequency not reported: Injection site reactions[Ref]


1. "Product Information. Seconal Sodium (secobarbital)." Lilly, Eli and Company (2001):

2. "Product Information. Seconal Sodium (secobarbital)." Marathon Pharmaceuticals (2010):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.