Results of barbiturate antiepileptic drug discontinuation on antipsychotic medication dose in individuals with intellectual disability.

Hanzel TE, Bauernfeind JD, Kalachnik JE, Harder SR.

Hanzel Consulting, New Prague, Minnesota, USA.

Five individuals with intellectual disability prescribed both a barbiturate antiepileptic drug (AED) and an antipsychotic medication were identified in a public residential facility. It was hypothesized that antipsychotic medication was prescribed at doses higher than necessary as a result of inadvertent barbiturate AED behavioural side-effects thought to be part of the underlying psychiatric or behavioural condition. To test this hypothesis, barbiturate AEDs were gradually reduced, and replaced with either carbamazepine or valproic acid, and antipsychotic medication was gradually reduced as well. Challenging behaviours, such as physical aggression, self-injurious behaviour and property destruction, were measured with a frequency count or partial interval recording, and retrospectively analysed for time periods of approximately 60 days before phenobarbital reduction, after phenobarbital discontinuation and after the lowest antipsychotic medication dose. Challenging behaviour collectively decreased by 81.5% after barbiturate discontinuation, mean antipsychotic medication dose significantly decreased from 146 mg day(-1) (SD = 98) to 106 mg day(-1) (SD = 88) chlorpromazine equivalence, and antipsychotic medication was discontinued in the cases of two individuals. Compared to the prebarbiturate AED reduction period, challenging behaviour collectively decreased by 96.3% after the lowest antipsychotic medication dose, which confirmed that reduced antipsychotic medication was not achieved at the expense of behaviour deterioration. The data supported the hypothesis that discontinuation of barbiturate AEDs results in decreased challenging behaviour and less antipsychotic medication.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10898379&dopt=Abstract barbiturate Butalbital Fioricet





The Brain Trauma Foundation. The American Association of Neurological Surgeons. The Joint Section on Neurotrauma and Critical Care. Use of barbiturates in the control of intracranial hypertension.

[No authors listed]

High-dose barbiturate therapy is efficacious in lowering ICP and decreasing mortality in the setting of uncontrollable ICP refractory to all other conventional medical and surgical ICP-lowering treatments. Utilization of barbiturates for the prophylactic treatment of ICP is not indicated. The potential complications attendant on this form of therapy mandate that its use be limited to critical care providers and that appropriate systemic monitoring be undertaken to avoid or treat any hemodynamic instability. When barbiturate coma is utilized, consideration should also be given to monitoring arteriovenous oxygen saturation as some patients treated in this fashion may develop oligemic cerebral hypoxia.

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Metocurine pharmacokinetics and pharmacodynamics in goats.

Antognini JF, Wood R, Gronert GA.

Department of Anesthesiology, University of California, Davis 95616-8634, USA.

Non-depolarizing muscle relaxants can facilitate surgery and anaesthesia in numerous species. and volatile inhalational anaesthetics such as isoflurane potentiate their action. We studied the effect of isoflurane on the pharmacodynamics and pharmacokinetics of metocurine in six goats. Each was studied twice: once during barbiturate-opiate anaesthesia and once during isoflurane anaesthesia. The evoked response to sciatic nerve stimulation was measured using a force transducer attached to the hoof. Metocurine was infused until approximately 80-90% blockade. Plasma metocurine concentration was determined by high-performance liquid chromatography. Isoflurane increased the potency of metocurine significantly; IC50 (the concentration in the effect compartment at 50% paralysis) was 70 +/- 15 ng/mL during isoflurane anaesthesia and 129 +/- 42 ng/mL during barbiturate-opiate anaesthesia (P < 0.03). Volume of distribution (63 +/- 18 mL/kg), clearance (1.6 +/- 0.4 mL/min.kg) and elimination half-life (99 +/- 9 min) during barbiturate-opiate anaesthesia were not significantly different during isoflurane anaesthesia: 64 +/- 25 mL/kg, 1.5 +/- 0.7 mL/kg.min, 116 +/- 16 min respectively. We conclude that, relative to barbiturate-opiate anaesthesia, isoflurane potentiates metocurine in goats.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8789701&dopt=Abstract barbiturate Butalbital Fioricet





Barbiturates inhibit K(+)-evoked noradrenaline and dopamine release from rat striatal slices--involvement of voltage sensitive Ca(2+) channels.

Hirota K, Kudo M, Kudo T, Kitayama M, Kushikata T, Lambert DG, Matsuki A.

Department of Anesthesiology, University of Hirosaki School of Medicine, 036-8563, Hirosaki, Japan.

The cellular target site(s) for anaesthetic action remain unclear. In rat striatal slices we have previously demonstrated that K(+)-evoked noradrenaline (NA) and dopamine (DA) release is mediated predominantly via P/Q-type voltage sensitive Ca(2+) channels (VSCC). Using this model of Ca(2+) dependent transmitter release we have evaluated the effects of anaesthetic and non-anaesthetic barbiturates. Rat brain striatal slices were incubated in the absence and presence of barbiturate for 10 min at 37 degrees C. The slices were then incubated for 6 min with 40 mM KCl. All anaesthetic barbiturates produced a concentration-dependent inhibition of K(+)-evoked NA and DA release. Non-anaesthetic barbiturate, barbituric acid was ineffective. The pIC(50) for NA and DA release (thiopental: 4.90+/-0.13 and 5.00+/-0.10, pentobarbital: 4.39+/-0.07 and 4.43+/-0.14, phenobarbital: 3.85+/-0.08 and 3.59+/-0.10, respectively) correlated with lipid solubility (NA: r(2)=0.999, DA: r(2)=0.987). We therefore suggest that barbiturates inhibit catecholamine release via an interaction with P/Q VSCC further implicating this channel in anaesthetic action.

Source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10984635&dopt=Abstract barbiturate Butalbital Fioricet