Nembutal, also known as pentobarbital, is a barbiturate medication that is primarily used as a short-term treatment for insomnia, as a sedative before surgery, and for the treatment of seizures. It is also used in some countries for euthanasia and assisted suicide for terminally ill patients.

The drug is trademarked and manufactured by the Danish pharmaceutical company Lundbeck, and is the only injectable form of pentobarbital approved for sale in the United States. In high doses, pentobarbital causes death by respiratory arrest. In the United States, the drug has been used for executions of humans. It is also one of the most popular drugs in euthanasia and drug assisted suicide, as it is known for being reliable and swift in its lethal effects.

As Nembutal falls into the barbiturate drug category, it is capable of producing a wide variety of side effects including all levels of CNS mood alteration from mild hypnosis to a deep coma. While in certain doses, the drug has an anesthesia effect, too much of the drug will produce death.

Common side effects include:

• Problems with memory or concentration,
• Excitement,
• Irritability,
• Aggression
• Confusion,
• Loss of balance or coordination,
• Nightmares,
• Nausea,
• Vomiting,
• Constipation,
• Headache,

Serious side effects can include:

• Hallucinations,
• Weak or shallow breathing,
• Slow heart rate,
• Weak pulse,
• Respiratory depression.