Paraldehyde

Paraldehyde is a cyclic trimer of acetaldehyde once used as a sedative, hypnotic, and anticonvulsant. Its clinical use declined as safer, more manageable drugs became available.

Acetaldehyde: Acetaldehyde is a volatile aldehyde formed during ethanol metabolism and used as an industrial chemical. Three acetaldehyde molecules combine to form paraldehyde.
Sedative: A sedative is a drug that reduces agitation and promotes calmness or drowsiness. Paraldehyde was administered to calm patients before safer sedatives displaced it.
Benzodiazepine: Benzodiazepines are drugs that enhance GABA-mediated inhibition and are used for anxiety, seizures, and sedation. They largely replaced paraldehyde for acute sedation and seizure treatment.
Respiratory depression: Respiratory depression is abnormally slow or shallow breathing that can impair oxygenation and become fatal. Excessive central nervous system depression from paraldehyde can endanger breathing.
Cyclic oligomer: A cyclic oligomer is a ring-shaped molecule assembled from a small number of repeating molecular units. Paraldehyde is the cyclic trimer of acetaldehyde.
Hypnotic: A hypnotic is a drug used to induce or maintain sleep. Paraldehyde’s stronger depressant effects made it a historical sleep-inducing medicine.
Barbiturate: Barbiturates are central nervous system depressants that enhance inhibitory signaling and can cause profound respiratory depression. They shared paraldehyde’s sedative uses but have distinct pharmacology and toxicity.
Aspiration pneumonitis: Aspiration pneumonitis is chemical lung inflammation caused by inhaling gastric contents or other irritating material. Vomiting or impaired consciousness during paraldehyde treatment can lead to aspiration.
Gamma-aminobutyric acid: Gamma-aminobutyric acid is the principal inhibitory neurotransmitter in the mammalian central nervous system. Paraldehyde’s central nervous system depression is associated with enhanced inhibitory signaling.
Anticonvulsant: An anticonvulsant is a drug that prevents or reduces epileptic seizures. Paraldehyde was used to suppress convulsions, including in urgent care.

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Wacker processRelated: It is one of several downstream products made from Wacker-process acetaldehyde.