Now-a-days mostly plastic syringes are available for use. In an emergency situation, is it safe to use a plastic syringe for administering paraldehyde injection in a child with status epilepticus?

C.R. Dass,
10-3-85/9, East Maredpally,
Secunderabad-26, A.P., India.

Reply

Paraldehyde has been in clinical use since 1882 for the treatment of status epilepticus in children as well as adults. It, however, is unstable, making storage and administration difficult; it also interacts with some plastics, which further complicates administration.

Reports of incompatibility of paraldehyde with disposable plastic syringes have been published as early as 1959 where the authors noted that paraldehyde dissolved a plastic syringe made of polystyrene within a relatively short period of time(1). An experiment involving the exposure of plastic disposable syringes to paraldehyde for a five-minute period showed increased resistance to injection, hairline fractures of the shaft and plunger in two minutes, and breaks in the shaft(2). Some brands of plastic syringes, however, have been reported to be stable in the presence of paraldehyde for upto 3 hours(3).

Plastic syringes are made of polypropylene. The commonly used plasticizer in these syringes is di (2-ethylhexyl) phthalate (DHEP) which can be leached by paraldehyde. DHEP has potential toxicity for the heart, lungs, liver and reproduc-tive organs in experimental animals. No specific defined lesions in humans have been associated with its use though risk remains. A necrotizing dermatitis and a plasticizer-induced hepatitis like syndrome have been described following extensive use of blood tubing. Polyneruopathies have been also described in one series of patients(4).

The rubber portion of the plunger causes leaching of 2-(2 hydroxyethylthio) benzothia-zide (HEB). It is used as a possible accelerator in the vulcanization of rubber. It may cause dermatological reactions in man and can displace bilirubin from albumin and hence increase the risk of kernicterus. In mice, HEB is neuro and hepatotoxic(4).

Thus considering the physical effects of paraldehyde on plastic syringes, paraldehyde should be administered by a glass syringe. In an emergency situation, however, the drug may be administered immediately by a plastic syringe.

Tarun Dua,
Department of Pediatrics,
All India Institute of Medical Sciences,
New Delhi 110 029, India.

1. Autian J, Dhorda CN. Evaluation of disposable plastic syringes as to physical incompatibilties with parenteral products. Am J Hosp Pharm 1959; 16: 176-179.

2. Addy DP, Alesbury P, Winter L. Paraldehyde and plastic syringes. Br Med J 1978; 2: 1434.

3. Lockman LA. Paraldehyde. In: Antiepileptic Drugs. Eds. Levy RH, Mattson RH, Meldrum BS. New York, Raven Press, 1995; pp 963-967.

4. Ellenhorn MJ, Schonwald S, Ordog G, Wasserberger J. Ellenhorn’s Medical Toxico-logy: Diagnosis and Treatment of Human Poisoning, 2nd edn. Baltimore, Williams and Wilkins, 1997; pp 1677-1681.