Paraldehyde adverse effects

The oldest anti-anxiety agent is undoubtedly alcohol and it is certain that this drug is still routinely self-administered for this purpose. Towards the end of the eighteenth century, bromide salts were used to relieve conditions akin to anxiety despite the risk of a characteristic toxic delirium, known as bromism . Alternative treatments, such as paraldehyde and chloral hydrate, were also widely used but these too had adverse effects the former can cause psychosis but the latter is still used as a sedative and anaesthetic agent. 

Paraldehyde is the cyclic trimer of acetaldehyde, a colorless or slightly yellow-colored liquid. It has been used as an anticonvulsant, but because of its adverse effects and because it is difficult to use it has been replaced by more modern agents. However, it is still sometimes used to treat status epilepticus that is resistant to first-line drugs (1). The usual adult rectal dose is 10-20 ml. 

Paraldehyde is metabolized in the liver to acetaldehyde (22), and the metabohsm of aldehyde by aldehyde dehydrogenase is inhibited by disulfiram, causing aldehyde toxicity. The adverse effects of this have been shown in experimental animals (23) and there have been reports of confusional psychosis in patients given disulfiram and paraldehyde (24). 

Historically, rectal or intravenous paraldehyde has been used for refractory GCSE. Although effective, it is extremely difficult to administer, is associated with serious adverse effects (e.g., hypotension, tachycardia, pulmonary edema, and polyethylene emboli), and is no longer manufactured in the United States. The only available formulation currently licensed is an enteral product that is difficult to obtain in a timely manner. If a rectal dose is given, it should be diluted 1 1 in vegetable oil and given every 20 minutes as needed via a rubber catheter."... 

Cyclic acetals of ketoses are prepared most commonly from acetone or benzaldehyde formaldehyde, acetaldehyde, butanone, and cyclohexanone have been used occasionally. These carbonyl reagents are frequently used directly, although such derivatives as 2,2-di-methoxy- or 2,2-diethoxy -propane (acetone dialkyl acetals), or l,l-dimethoxyethane (acetaldehyde diethyl acetal), are often employed in experiments in which intermediate acetals are of interest,or in which the presence of water in the reaction mixture adversely affects the yield of products. A polymeric form of an aldehyde is the reagent to be preferred whenever the monomer is volatile for example, acetaldehyde is often used in the form of a trimer, paraldehyde, and formaldehyde is employed as formalin solution, as paraformaldehyde, or as polyoxymethylene. An excess of the carbonyl reagent is generally used as the solvent, and the condensation is usually effected at room temperature. 

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