Immune-mediated reactions to althesin (alphaxalone)

Final Report on the Safety Assessment of Peg-30,-33,-35,-36, ANd-40 Castor Oil and Peg-30 and-40 Hydrogenated Castor Oil

PEG Castor Oils and PEG Hydrogenated Castor Oils are a family of polyethylene glycol derivatives of castor oil and hydrogenated castor oil that are used in over 500 formulations representing a wide variety of cosmetic products. They are used as skin conditioning agents and as surfactants (emulsifying and or solubilizing agents). The PEG Castor Oils and PEG Hydrogenated Castor Oils include various chain lengths, depending on the quantity of ethylene oxide used in synthesis. Although not all polymer lengths have been studied, it is considered acceptable to extrapolate the results of the few that have been studied to allingredients in the family. Because a principal noncosmetic use of PEG Castor Oils is as solvents for intravenous drugs, clinical data are available that indicate intravenous exposure can result in cardiovascular changes. Results from animal studies indicate very high LD50 values, with some evidence of acute nephrotoxicity in rats but not in rabbits. Short-term studies with intravenous exposure produced some evidence of toxicity in dogs but not in rabbits. Intramusuclar injection produced no toxicity in several species, including dogs. Subchronic oral studies also were negative. No dermal or ocular irritation was observed in studies in rabbits. Irritation was seen during induction, but no sen-sitization was found on challenge in guinea-pig studies using up to 50% PEG-35 Castor Oil; however, thisingredient was found to be a potent adjuvant in guinea pigs and mice. No evidence of developmental toxicity was seen in mice and rat feeding studies. Theseingredients, tested as vehicle controls, produced no mutagenic or carcinogenic effect. Clinical data are generally negative for irritation and sensitization, although some anaphylactoid reactions have been seen in studies of intravenous drugs in which PEG-35 Castor Oil was used as the vehicle. Because the maximum concentration used in animal sensitization studies was 50% for PEG Castor Oils and 100% for PEG Hydrogenated Castor Oils, it was concluded that PEG Castor Oils are safe for use in cosmetic formulations up to a concentration of 50% and that PEG Hydrogenated Castor Oils are safe as used in cosmetic formulations.

The incidence of anaphylaxis following intravenous phytonadione (vitamin K1): a 5-year retrospective review

BACKGROUND

Phytonadione (vitamin K1) administered intravenously (i.v.) has been associated with anaphylaxis, although the incidence is not known. The anaphylaxis is thought to be attributable to the solubilizing vehicle, polyethoxylated castor oil (Cremophor EL, BASF AG, Ludwingshafen, Germany).

OBJECTIVE

To estimate the incidence of anaphylaxis after i.v. administration of phytonadione.

METHODS

A retrospective review of anaphylaxis after i.v. phytonadione over a 58-month period at a large academic center was performed. During the period of the study a protocol for the administration of i.v. phytonadione was in place. A review of computerized records and survey of staff identified cases of anaphylaxis meeting predefined inclusion criteria. In addition, a literature review was performed for articles concerning anaphylaxis after i.v. phytonadione.

RESULTS

Over the 58 months of the study, a total of 6,572 doses of i.v. phytonadione were administered. Two cases of anaphylaxis after i.v. phytonadione were identified. The incidence of anaphylaxis was 3 per 10,000 doses with 95% confidence intervals of 0.04 to 11 per 10,000 doses. The literature review identified 14 cases meeting inclusion criteria with no reviews of the literature or estimates of incidence.

CONCLUSIONS

The incidence of anaphylaxis after i.v. phytonadione is overall comparable or slightly less than other drugs known to cause anaphylaxis. We do not recommend routine pretreatment with antihistamines or corticosteroids before administration of phytonadione.

Lessons for management of anaphylaxis from a study of fatal reactions

BACKGROUND

The unpredictability of anaphylactic reactions and the need for immediate, often improvised treatment will make controlled trials impracticable; other means must therefore be used to determine optimal management.

OBJECTIVES

This study aimed to investigate the circumstances leading to fatal anaphylaxis.

METHODS

A register was established including all fatal anaphylactic reactions in the UK since 1992 that could be traced from the certified cause of death. Data obtained from other sources suggested that deaths certified as due to anaphylaxis underestimate the true incidence. Details of the previous medical history, the reaction and necropsy were sought for all cases.

RESULTS

Approximately half the 20 fatal reactions recorded each year in the UK were iatrogenic, and a quarter each due to food or insect venom. All fatal reactions thought to have been due to food caused difficulty breathing that in 86% led to respiratory arrest; shock was more common in iatrogenic and venom reactions. The median time to respiratory or cardiac arrest was 30 min for foods, 15 min for venom and 5 min for iatrogenic reactions. Twenty-eight per cent of fatal cases were resuscitated but died 3 h-30 days later, mostly from hypoxic brain damage. Adrenaline (epinephrine) was used in treatment of 62% of fatal reactions but before arrest in only 14%.

CONCLUSIONS

Immediate recognition of anaphylaxis, early use of adrenaline, inhaled beta agonists and other measures are crucial for successful treatment. Nevertheless, a few reactions will be fatal whatever treatment is given; optimal management of anaphylaxis is therefore avoidance of the cause whenever this is possible. Predictable cross-reactivity between the cause of the fatal reaction and that of previous reactions had been overlooked. Adrenaline overdose caused at least three deaths and must be avoided. Kit for self-treatment had proved unhelpful for a variety of reasons; its success depends on selection of appropriate medication, ease of use and good training.

Efficacy evaluation of a novel submicron miconazole emulsion in a murine cryptococcosis model

Submicron emulsions of miconazole were stabilized by using a combination of three emulsifiers comprising phospholipids, poloxamer, and deoxycholic acid (DCA). The presence of DCA was vital for prolonged emulsion stability owing to its contribution to the elevated zeta potential of the emulsion. Further, the results by the phospholipid surface labelling colorimetric technique clearly suggested that poloxamer molecules interacted with phospholipid polar-head groups of the mixed DCA-phospholipid interfacial film, resulting in the stabilization of the emulsion by a steric enthalpic entropic mechanism. The plain emulsion vehicle was well tolerated up to a dose of 0.6 ml injected i.v. to BALB/c mice. The maximum tolerated dose of miconazole was 80 and 250 mg/kg in Daktarin i.v. (a marketed product) and emulsion, respectively, showing an improved safety ratio of 1 to 3 in favor of the emulsion. These results tended to confirm that the adverse effects associated with Daktarin i.v. injection should be associated with the vehicle rather than with the miconazole itself. In a murine cryptococcosis model, only one mouse out of ten remained alive by day 15 in the infected group treated with Daktarin i.v., while in the miconazole emulsion treated group, mice began to die from day 16 up to day 25 post inoculation. Thus, the multiple-dose treatment with the miconazole emulsions improved the protection offered to the infected mice. However, the therapeutic levels of miconazole that were reached in the target organ (brain) were lower than those required for complete eradication of Cryptococcus neoformans, which is known to multiply preferentially in the brain.

Incorporation of alphaxalone into different types of liposomes

The poor solubility of steroid anaesthetics in water has been a serious drawback in the development of clinically acceptable intravenous formulations. The use of Cremophor EL to solubilize steroids such as alphaxalone led to unacceptable hypersensitivity reactions and consequent withdrawal of this anaesthetic. In principle, liposomes can act as a safe solvent for the intravenous administration of alphaxalone. We report the incorporation of [14C]acetylated alphaxalone in both multilamellar vesicles and stable plurilamellar vesicles prepared from a range of amphiphiles including synthetic polyhydroxyl lipids. For both types of preparations, addition of cholesterol to phosphatidylcholine-based lipids caused an increase in encapsulation efficiency. Maximum encapsulation was achieved with the stable plurilamellar vesicle preparation of 1-stearyl-2-myristylglycerate-3, N-methylglucamine:cholesterol:egg phosphatidylcholine (78%). The rate of efflux of this anaesthetic from a range of liposomes was measured in serum. The highest rate (85% after 30 min) was observed with an equimolar egg phosphatidylcholine:cholesterol stable plurilamellar vesicle preparation. From these studies it can be concluded that liposomes offer a suitable alternative for intravenous delivery of steroidal anaesthetics.

Effect of propofol on cerebrospinal fluid pressure and cerebral perfusion pressure in patients undergoing craniotomy

The effects of propofol on cerebrospinal fluid pressure, mean arterial pressure, cerebral perfusion pressure and heart rate were studied during induction, tracheal intubation and skin incision in 23 patients scheduled for elective craniotomy. Premedication consisted of midazolam 0.1 mg/kg intramuscularly and metoprolol 1 mg/kg orally. Measurements were made or derived at time zero and 0.5, 1, 1.5, 2 and 3 minutes after an induction dose of propofol 1.5 mg/kg. A continuous infusion of propofol was started at time zero at a rate of 100 mg/kg/minute. Fentanyl 2 micrograms/kg was added before tracheal intubation, application of the pin head holder and skin incision. Cerebrospinal fluid pressure and mean arterial pressure decreased significantly 2 minutes after propofol alone, by 32% and 10% respectively, while a cerebral perfusion pressure above 70 mmHg was maintained. Heart rate did not change. Propofol combined with moderate dose of fentanyl, obtunded the usual cerebrospinal fluid and arterial pressure responses to intubation and other noxious stimuli. Thus propofol seems to be a suitable intravenous anaesthetic agent for induction and maintenance in neuroanaesthesia.

[Epidemiologic characteristics of 21 peranesthetic anaphylactoid accidents observed in a population of 12,855 surgically treated patients]

A study of anaphylactoid reactions (AR) observed between September 1982 and September 1983 was carried out in the surgical departments of a French regional hospital. The patients who had presented clinical symptoms suggesting an AR (bronchospasm, collapse, tachycardia, with or without skin rash) during a general anaesthesia were included in this study. A precise history of previous anaesthesias and allergy was taken; allergological testing was carried out six to eight weeks after the AR. It included intradermal skin tests (ST) and a human basophil degranulation test (HBDT) with the suspected drugs. Out of 12,855 patients operated on under general anaesthesia in the hospital, 21 AR were seen during the year under study, in 18 women and 3 men, of median age 27 years (extreme values: 11 and 62). The median number of previous anaesthesias was 2 (extreme values: 0--in 4 cases- and 22). Cardiocirculatory abnormalities were the most frequent clinical symptoms of the AR: they consisted of decreased arterial pressure in 13 cases, with 8 cases of vascular collapse. Respiratory symptoms were less frequent but severe bronchospasm was observed in 5 cases. Skin rashes were seen simultaneously in 13 out of the 21 observations. A history of allergy was found in 11 patients. Total IgE serum concentration averaged 134 kU X 1(-1) (extreme values: 32-378). Results of histamine-sensitivity skin tests were not significantly different from those observed in a control group. Calcemia and magnesemia were in the normal range. One to four drugs were tested in each patient: 41 tests combining ST and HBDT were carried out.(ABSTRACT TRUNCATED AT 250 WORDS)

Intravenous sedation for the intubated and spontaneously breathing patient in the intensive care unit

A technique is described for the management of post-operative patients who have undergone major craniofacial surgery. Under supervision on the Intensive Care Unit, the patients breathe humidified, oxygen-enriched air through a naso-tracheal tube. Sedation and analgesia are provided by continuous infusions of etomidate (variable rate) and fentanyl (fixed rate), administered by volumetric infusion pumps (IMED 922). Six patients have been studied in detail and our results are presented. In conjunction with fentanyl, a mean infusion rate of 3.72 micrograms . kg-1 . min-1 of etomidate provided good sedation and analgesia, without clinically significant respiratory depression. The patients found the technique very acceptable and no side-effects were noted.

Hypersensitivity reactions to Althesin infusion: measurement of complement involvement

Two cases of hypersensitivity reactions in the course of slow infusion of Althesin are reported. Serial examination of their complement system showed a marked activation of the alternate pathway which returned almost to normal within 24 hours.

Immunological and non-immunological mechanisms involved in adverse reactions to drugs

This communication reviews the mechanisms involved in anaphylactic and anaphylactoid reactions to intravenous drugs used in anaesthesia. Although the mechanisms involved are pertinent to other drugs and substances used in clinical practice, the use of the intravenous route makes this a particularly worrying problem in anaesthetic practice. Despite the similarity of the clinical manifestations to those expected from immediate immunological hypersensitivity (anaphylaxis), relatively few reactions involve antibodies. Instead, a variety of mechanisms occur where activation of the blood inflammatory response systems, particularly complement, may be either primary or secondary to activation of the coagulation or fibrinolytic cascades of the blood clotting mechanisms. Immediate anaphylactoid reactions, manifest in the release of vasoactive substances such as histamine, may therefore pose very minor problems compared with coagulation problems arising in the peri- and post-operative period. It is important to discover the mechanism of all adverse reactions not only if these are to be avoided in the reactants in the future but also because of the necessity for devising suitable prophylactic and therapeutic measures for general use. The practical problems of such investigations are explored with particular reference to the laboratory investigation of subclinical reactions in terms of plasma histamine release and changes in blood leucocyte distribution.

Epidemiology of adverse reactions in anaesthesia in the United Kingdom

Adverse reactions to intravenous anaesthetics and muscle relaxants are characterised by peripheral vasodilatation with oedema, hypotension, tachycardia, bronchospasm and (more rarely) vomiting and abdominal cramps. The number of published cases in the U.K. is rising yearly. The frequency with all cremophor-containing drugs is about 1 in 1,000 cases but the number recorded following other induction agents is increasing. Most reactions following muscle relaxants have been documented in other countries but this probably reflects local interpretation rather than true geographical differences. The incidence could be reduced by avoiding the use of all cremophor-containing drugs and death from actual incidents could be prevented by having adequate resuscitation measures available.

Histamine release and hypotensive reactions in dogs by solubilizing agents and fatty acids: analysis of various components in cremophor El and development of a compound with reduced toxicity

Anaphylactoid reactions in man following administration of drugs solubilized with cremophor El (polyethylenglycolglycerol riconoleate) are a considerable clinical problem. Since these reactions occur in dogs on first exposure and in pigs on second exposure, the 'dog model' was used in this communication to analyse components and chemical modifications of cremophor El and its components for their clinical effects, their hypotensive actions and their histamine-releasing capacity. Two series of experiments in 1978 and 1980 were performed in 144 adult mongrel dogs of both sexes. In these studies histamine release was not related to the effect of the solubilizing agents as tensides and was elicited by rather low doses (about 10--100 mg/kg i.v.). The effect of these substances on blood pressure and on blood histamine levels was connected with distinct chemical features: the most potent compounds were oxethylated and additionally esterified unsaturated or hydroxylated fatty acids. Several phases in hypotensive reactions were observed, including an immediate response, a delayed blood pressure response and a late response about 15--20 min after injection. Only the delayed response was associated with histamine release. The combination of cardiovascular effects and histamine release was fatal on some occasions indicating that histamine release can be dangerous. Compared to cremophor El, the tenside effect was equal, but the toxicity was reduced in oxethylated 12-hydroxystearic acid. It is recommended that this solubilizer should be used in further extended studies in animals and - if these are successful - in clinical trials.

Suspected anaphylactic reaction to Cremophor EL

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Delayed adverse responses to both methohexitone and Althesin

A patient who reacted to both methohexitone and Althesin on separate occasions is described. On each occasion the reaction was delayed following anaesthesia. Underlying chronic infection had sensitised the patient's complement pathway, allowing it to be activated by two unrelated intravenous anaesthetic agents.

Adverse reactions following fazadinium-thiopentone induction

Three cases of hypersensitivity to an anaesthetic induction with fazadinium and thiopentone are described. One reaction was fatal. Two patients had documented and the third presumptive previous exposure to thiopentone, and all had a history of allergy (skin rash) to penicillin. None of the patients had received fazadinium before. The possibility that fazadinium contributed to the severity of the reactions is conjectural.

Intradermal testing in the diagnosis of acute anaphylaxis during anaesthesia--results of five years experience

Intradermal testing has been used in the diagnosis of acute anaphylactic reactions during anaesthesia in 51 patients. Positive results occurred in 32 patients and confirmation was possible in 26. Only in one case did a combination of history and intradermal testing not give a diagnosis. Nine of the negative results were confirmed. Intradermal testing is of no value in the diagnosis of reactions to local anaesthetics or colloids but has great value in determining the cause of reactions due to induction agents or muscle relaxants if performed under controlled conditions. It is safe, and requires no expertise in performance or interpretation.

Severe bronchospasm in an asthmatic patient following alcuronium and D-tubocurarine

An asthmatic patient developed intense bronchospasm immediately following the administration of alcuronium and d-tubocurarine in the same anaesthetic. Intradermal test was positive for both of these drugs but negative for thiopentone and suxamethonium, both of which were given prior to alcuronium. The differential diagnosis and the possible mechanism of the reaction are discussed.

Physostigmine in open-heart surgery. Reversal of hyoscine supplementation of morphine-oxygen-air-relaxant anaesthesia

The use of physostigmine salicylate to reverse hyoscine supplementation of morphine-oxygen-air relaxant anaesthesia has been studied in twenty open-heart surgery patients and found to be both reliable and innocuous.

Anaphylactic reactions to gallamine triethiodide

Three cases of severe anaphylaxis to gallamine triethiodide are described. All reported cases of anaphylaxis to gallamine have occurred in women, and all the confirmed cases in Australasia. There is evidnece that women may be exposed to some substance which leaves them sensitive to gallamine triethiodide.