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Drug dosage identifier

Paraldehyde

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Dose and administration

See Possible adverse effects

  1. Slow intravenous infusion of DILUTED paraldehyde.
    Administered as a 2 hour infusion2.
    Dose range is 0.2 to 0.4 ml (pure paraldehyde) /kg as 2 hour infusion. This is equivalent to 4 to 8ml (of DILUTED SOLUTION ) /kg.- see Administration. 
    The dose may be repeated to NOT MORE than 0.4ml (pure paraldehyde)/kg in 24 hours.
  2. Rectal enema: 0.2 to 0.3ml (of pure paraldehyde)/kg (this volume of paraldehyde must be diluted before administration)9 - see Administration.

Indications

(For term or near term infants)

  1. Seizure/status epilepticus refractory to initial therapy with phenobarbitone and phenytoin.

Contraindications

  1. Known hypersensitivity to paraldehyde.
  2. Severe hepatic insufficiency, bronchopulmonary disease5, or gastric disease.

Precautions

  1. Hepatic dysfunction.
  2. Cardiovascular disease5.
  3. Use only freshly opened ampoules. Do not use paraldehyde if it is brownish colour or has a sharp penetrating odour of acetic acid - this indicates decomposed paraldehyde which is dangerous if administered5.
  4. Avoid contact between paraldehyde and rubber; avoid use of plastic syringes because of solvent action of paraldehyde.

Drug interactions

Possible concomitant drug therapy

CNS Depressants (e.g. phenobarbitone, phenytoin):  possible potentiation of CNS depression.

Clinical pharmacology

Paraldehyde is a hypnotic and sedative with anticonvulsant effects. Its possible action is to depress parts of the CNS including the ascending reticular activating system to cause an imbalance between inhibitory and facilitatory mechanisms5. The drug is used to control seizures in infants, including those refractory to phenobarbitone and phenytoin, and is as effective as phenobarbitone in the emergency treatment of convulsions in children. Adult metabolism of paraldehyde involves 80% conversion to acetaldehyde, which is oxidised by aldehyde dehydrogenase to acetic acid. Unmetabolised drug is largely excreted unchanged through the lungs with a smaller amount excreted in the urine6. The drug diffuses into the CSF and has a rapid onset of action. At therapeutic doses, paraldehyde has little effect on respiration and blood pressure5.

Possible adverse effects

  1. Intravenous injection may be hazardous and may cause pulmonary oedema and haemorrhage, hypotension and cardiac dilatation, and circulatory collapse 5.
  2. Rectal administration may result in rectal irritation.
  3. Skin rash; trembling; unusual sweating5.
  4. Overdosage manifests as rapid laboured breathing, due to damage to lungs and to acidosis. Respiratory depression and coma; metabolic acidosis, hepatic and renal damage may also occur 6. Diagnosis of paraldehyde overdose may be aided by the characteristic odour of the drug on the breath6.
  5. Gastrointestinal irritation.

Special considerations

Emergency action for overdosage: Supportive measures:

  • Ventilation
  • Correction of hypotension
  • Correction of metabolic acidosis

Management of Paraldehyde administration

Description

  • Paraldehyde injection is a colourless or pale yellow transparent liquid with a strong characteristic odour.
  • It contains hydroquinone as an antioxidant - this is a non-therapeutic additive.
  • It is available in 5 ml ampoules.

NB: The reference for paraldehyde2 gives a dose range of 0.2 to 0.4 g/kg every 24 hours. Paraldehyde injection is NOT a weight/volume preparation i.e. it is pure paraldehyde liquid. We must therefore make an assumption that the researchers for this article used the relative density of paraldehyde as a reference for the g/kg dose. The relative density of paraldehyde is 0.9966 i.e. 1g=1ml and 0.2g=0.2ml.

Prescription

Slow intravenous infusion

Charted under continuous drugs on the Level 3 Infant Drug Administration Record, giving:

  • amount of drug
  • base fluid, type and volume
  • rate in ml/hour
  • total amount to be infused
  • ml/kg/dose

Rectal enema:

Stat dose to be charted on stat page of prescription chart in ml/dose

Administration

Slow Intravenous Infusion over 2 hours (preferred method).

  1. Dilute paraldehyde immediately prior to use.
  2. Make a 5% solution. Using a glass syringe to draw up the paraldehyde:
    1. Add 2.5ml Paraldehyde to
    2. 47.5ml Sodium chloride 0.9%
    3. Giving 50.0ml total volume to an empty McGaw Partial Additive Bag (PAB).
  3. Connect a Gemini Administration Set 2260 (for Nitroglycerin and Fat Emulsions) to the PAB.
  4. Administer through a Gemini PCI Volumetric Infusion Pump over 2 hours (4-8 ml/kg, of diluted paraldehyde i.e. 5% solution) directly into cannula (Do not use minibore extension).
  5. Diluted paraldehyde must be administered via bag and tubing made of polyethylene or polypropylene but not polyvinyl chloride. Never use through a 3-way stopcock. Cover tubing with tinfoil to protect from light.
  6. Incompatible with everything but sodium chloride 0.9%. Do NOT mix with other drugs, IV solutions, blood or blood products.
  7. Flush line with sodium chloride 0.9% before and after infusion of paraldehyde.

Rectal Enema

Dilute before administration with an equal volume of olive oil8.

Observation and documentation

  1. The baby is attached to a continuous cardiac respiratory monitor and managed by a nurse with Neonatal IV Drug Certification.
  2. Document heart rate, respiratory rate, and blood pressure hourly while infusion is in progress.
  3. Observe for and document seizure activity.
  4. Observe for decreased urinary output.

Storage

  • Unopened - store at room temperature <25°C.
  • Discard in a sharps container in a non-clinical area after use (unpleasant odour).

Selected references

  1. Giacoia GP, Gessner PK, Zaleska MM, Boutwel WC. Pharmacokinetics of paraldehyde disposition in the neonate. J Pediatr 1984; 104: 291-296.
  2. Koren G, Butt W, Rachjot P et al. Intravenous paraldehyde for seizure control in newborn infants. Neurology 1986; 36: 108-11.
  3. Bostom B. Paraldehyde toxicity during treatment of status epilepticus. Am J Child 1982; 136: 414-415.
  4. Evans D, Levene M. Neonatal seizures. Arch Dis Child Fetal Neonatal Ed. 1998;78:F70-75
  5. Paraldehyde Data Sheet. DBL Ltd.; 1993: Mulgrave.
  6. Reynolds JEF (Ed.) Martindale: The Extra Pharmacopoeia. (31st ed). Royal Pharmaceutical Society; 1996: London
  7. McEvoy GK (Ed.) AHFS 98 Drug Information. American Society of Health-System Pharmacists; 1998: Bethesda
  8. Loe E. et al. Paediatric Pharmacopoeia, Royal Children's Hospital Melbourne and Leicester Royal Infirmary Children's Hospital. WB Saunders Co. Ltd; 1998: London
  9. Alder Hey Book of Children's Doses (6th ed.) Pharmacy Dept. Royal Liverpool Children's Hospital (Alder Hey); 1994 (with 1996 amendments): Liverpool.

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Document Control

  • Date last published: 31 August 1999
  • Document type: Drug Dosage Guideline
  • Services responsible: ADHB Pharmacy, Neonatology
  • Editor: Sarah Bellhouse
  • Review frequency: 2 years