Ketamine in acute intermittent porphyria--dangerous or safe?

Clinical practice guideline for emergency department ketamine dissociative sedation in children

We present an evidence-based clinical practice guideline for the administration of the dissociative agent ketamine for emergency department pediatric procedural sedation and analgesia. Substantial research in recent years has necessitated updates and revisions to the widely disseminated 1990 recommendations. We critically discuss indications, contraindications, personnel requirements, monitoring, dosing, coadministered medications, recovery issues, and future research questions for dissociative sedation.

Ketamine sedation for pediatric procedures: Part 2, Review and implications

Ketamine produces rapid and consistent pediatric sedation with a predictable onset and recovery time. A wide margin of safety is afforded without the respiratory and cardiovascular depression commonly seen with alternative agents. The efficacy of ketamine is well established in anesthesia and dentistry and has extensive applications in other specialties. Ketamine sedation facilitates superior technical and cosmetic results while minimizing emotional trauma to distraught children. The much-feared complications of aspiration and laryngospasm are extremely rare when ketamine is used with proper precautions. Ketamine deserves increased use in the ED, and we advocate additional clinical investigation in this setting.

[Anesthesia and hepatic porphyria]

Three of the acute hepatic porphyrias, acute intermittent porphyria, variegata porphyria and hereditary coproporphyria, are characterized by an idiosyncratic reaction to many common drugs; the resulting excessive excretion of porphyrin precursors is responsible for episodes of acute neurological dysfunction. This review aimed to focus the attention of the anaesthesiologist on the porphyrinogenic properties of all the drugs used in anaesthesia and intensive care. An outline of the chemistry of porphyrins and the enzymatic pathways were recalled, so as to place the acute porphyrias in their proper perspective. There follows a reminder of the clinical aspect of acute porphyric crises. The part played by drugs is then assessed from clinical and laboratory data concerning their porphyrinogenicity. Those drugs for which there is conflicting evidence regarding their safe use in porphyric patients are discussed: propofol, ketamine, benzodiazepines, etomidate, local anaesthetics. Recommendations supported by clinical and experimental data are given, especially the results obtained with the chick embryo liver model. Treatment of the acute crisis is provided, with particular emphasis on the use of haematin. The anaesthetic management of hepatic porphyric patients is described. Those drugs which are well-known porphyrinogenic compounds in the chick embryo liver must be excluded from use for anaesthesia in the porphyric patients, even if they have been observed to be innocuous in rare cases of asymptomatic patients. Finally, recommendations for anaesthesia in symptomatic cutanea porphyria are given.

Is propofol a safe agent in porphyria?

A case is presented of the use of a propofol infusion for anaesthesia in a patient with known variegate porphyria. Urinary screening for porphyrins demonstrated a marked increase after this anaesthetic, but there were no clinical symptoms.

Induction of anaesthesia with ketamine during an acute crisis of hereditary coproporphyria

An appendectomy operation was undertaken in a 29-year-old patient with signs of an acute crisis of hereditary coproporphyria. Anaesthetic induction with ketamine 75 mg IV was uneventful. The safety of ketamine in patients with coproporphyria is discussed.

[Peridural anesthesia with procaine and fentanyl in a parturient with acute intermittent porphyria]

Acute intermittent porphyria is one of three severe hepatic porphyrias. Clinical manifestations include intermittent acute attacks of abdominal pain and neuropathy with an occasionally outcome. These attacks are often precipitated by endogenous (menstrual cycle and pregnancy in women) or exogenous factors (porphyrinogenic drugs). An epidural analgesia was performed during the labour of a pregnant woman with acute intermittent porphyria just after an acute attack of abdominal pain. Analgesia was obtained using procaine and fentanyl. The choice of drugs was based on available clinical reports and experimental studies of the porphyrinogenicity of drugs in animal models (rat in vivo and chick embryo in ovo).