Failure of absorption of baclofen after rectal administration.

We wished to determine the degree to which baclofen was absorbed from an aqueous vehicle after rectal administration. A comparison was made to absorption after oral administration. After oral administration, the baclofen half-life was 2.3 to 3.4 hours and peak serum concentrations were achieved from 1 to 2.1 hours after administration. No measurable absorption was observed after rectal administration of the drug in any subject. Rectal administration of baclofen is not a clinically sound treatment option when oral administration of the drug is not possible. For patients receiving chronic baclofen therapy, other medications such as a benzodiazepine should be considered at times when oral administration of medication is not possible.

Failure of absorption of gabapentin after rectal administration.

PURPOSE: We wished to determine the extent of absorption of gabapentin (GBP) after rectal administration to children on maintenance therapy. METHODS: Two children scheduled for extensive surgery received GBP rectally and orally. A pharmacokinetic profile was derived after each route of administration. RESULTS: Serum GBP levels after rectal administration decreased at a rate similar to their rate of decrease after oral administration. However, GBP concentrations were much lower after rectal administration; therefore, we concluded that the aqueous solution was poorly absorbed rectally. The GBP half-life (t1/2) for the 2 children after oral doses were 4.2 and 4.8 h. CONCLUSIONS: Rectal administration of GBP is not satisfactory when oral administration is interrupted. When oral GBP therapy is temporarily discontinued, clinicians should consider administration of alternative antiepileptic drugs (AEDs) that can be administered parenterally or rectally.

Outcome of severe anoxic/ischemic brain injury in children.

The outcome of 25 children who had anoxic or ischemic brain injuries at 2 months to 14 years of age is reported. Follow-up was from 1 to 14 years after injury; causes were near-drowning, 11; suffocation, 7; cardiac arrest, 3; electrocution with cardiac arrest, 2; strangulation, 1; aborted sudden infant death syndrome, 1. All patients were unconscious for at least 24 hours. Of 11 remaining in vegetative states, 5 died. Seven children regained some language skills and are in special education or self-contained classrooms. Seven are profoundly impaired and show only a social smile. Cognitive and motor outcomes were correlated with the severity of injury as indicated by the duration of unconsciousness. All children who regained language skills or the ability to walk were unconscious less than 60 days. Dystonic rigidity was observed in all children who were nonambulatory. Outcome was also correlated with the cause of injury; mortality, cognitive outcome, feeding outcome, and duration of unconsciousness were all worse in children with near-drowning.

Outcome of children with prolonged unconsciousness and vegetative states.

The outcomes of 60 children unconscious for 90 days or longer following acquired brain injury are reported. Eight children who died had remained in persistent vegetative states. As expected, most neurologic improvement occurred within the first year after injury, although some delayed improvements were observed. Outcomes were strongly correlated with causes of brain injury. Better cognitive and motor function was observed with nonanoxic injuries. No child in this report with anoxic brain injury regained functional cognitive or motor skills, although 3 became socially responsive. The remarkable contrast with adults following acquired brain injury is the significantly longer survival of children. The only children who died had remained in persistent vegetative states.

External leakage from feeding gastrostomies in patients receiving valproate sprinkle.

We reviewed the incidence of external leakage from feeding gastrostomies in 8 patients who received valproate sprinkle (VPA-S). We also identified a control group of 31 children with feeding gastrostomies who were also cared for in our clinic, but who did not receive VPA-S. All patients in both groups have had their feeding gastrostomy greater than or equal to 6 months. Four of 8 children who received VPA-S through feeding gastrostomies developed problems with recurrent external leakage. The incidence of external leakage in our control group of children who had not received VPA-S was 2 in 31 (6.4%). We hypothesize that the external leakage is caused by adherence of the undissolved VPA-S particles to the exterior of the tube, preventing close approximation of the tube to the gastrostomy stoma. In most cases, VPA-S could continue to be administered and the problem of leakage reduced if the tubes were more frequently changed and/or a larger size were used. Complications with either leakage or occlusion were noted in all patients with the button feeding tube who had received VPA-S. Because of the especially high complication rate associated with administration of VPA-S in children with the "button" feeding tubes, we discourage VPA-S administration to children with that device.

Comparison of sprinkle versus syrup formulations of valproate for bioavailability, tolerance, and preference.

We compared a new coated-particle formulation of valproate (Depakote Sprinkle) capsules with valproic acid (Depakene) syrup for bioavailability, side effects, and patient and parent preference. Twelve children with epilepsy, aged 5 to 16 years, participated in this randomized, two-period, crossover study. They were assigned to a 7-day regimen with one formulation and then crossed over to the other; the drug was given every 12 hours. On day 7, blood samples collected during a 12-hour period were analyzed for the presence of valproate. At the study's end, parents and children were asked structured questions regarding formulation preference and adverse events. The extent of absorption from sprinkle equaled that from syrup (relative bioavailability = 1.02), but absorption was slower (time to maximum concentration = 4.2 vs 0.9 hour; p less than 0.01). Fluctuations in serum concentrations were less with sprinkle (34.8% vs 62.3%; p less than 0.01). Sprinkle was preferred by 9 of the 12 parents because of east of administration, and by nine of the children because of improved palatability. We conclude that sprinkle may be substituted for syrup without changing the daily dose. Furthermore, sprinkle, because of its prolonged absorption, may be given every 12 hours to children receiving monotherapy. Compliance may be enhanced because of the more convenient dosing schedules and the high degree of patient and parent acceptance.

Home use of rectal diazepam for cluster and prolonged seizures: efficacy, adverse reactions, quality of life, and cost analysis.

From 1982 through 1987, 128 families, who were instructed in the use of rectally administered diazepam (R-DZP) for the treatment of severe epileptic seizures, were surveyed. Sixty-seven families returned questionnaires and met inclusion/exclusion criteria; the results were used to analyze the medical, psychosocial, and economic impact of this program during the first year following instruction. Twenty-six families did not use R-DZP, primarily because of patient improvement. Among families using R-DZP, a total of 428 doses were administered to 41 children. R-DZP was effective in controlling seizures in 85% of patients. Adverse reactions usually were mild, consisting of drowsiness and/or behavioral changes. Compared to the year prior to instruction, emergency room visits decreased in both R-DZP-treated and -nontreated children; however, cost-savings were greater for the R-DZP group ($1,039.00 vs $420.00 per patient per year). Improvements in quality of life associated with the availability of R-DZP were observed by 58% of users and 27% of nonusers which included improved management of their children's seizures, increased flexibility in family activities, and greater peace of mind. R-DZP appears to be a practical method in the effective treatment of severe seizures at home.

Relative bioavailability of rectally administered phenobarbital sodium parenteral solution.

Rectal administration of antiepileptic drugs may be a useful alternative route when oral administration is not possible due to illness, surgery, or status epilepticus. Although parenteral administration often replaces oral administration in these circumstances, there is not always a desirable intravenous line available or repeated intramuscular injections may not be practical. The purpose of this study was to determine the relative bioavailability and time course of absorption of the commercially available parenteral phenobarbital sodium solution administered rectally in comparison with the same preparation given intramuscularly. Seven healthy adult volunteers were given phenobarbital 5 mg/kg intramuscularly and rectally five weeks apart. Eighteen blood samples were drawn over 288 hours. Pharmacokinetic parameters following intramuscular versus rectal administration were the following: area under the curve 5916 vs. 5253 mumol.h/L; half-life 112 vs. 113 h; time to maximum concentration 2.1 vs. 4.4 h; and maximum serum concentration 36.2 vs. 31.4 mumol/L. Mean relative bioavailability for rectal phenobarbital was 90 percent. Therefore, the parenteral phenobarbital sodium solution given rectally is well absorbed and provides a useful alternative route of administration.

Relative bioavailability of rectally administered carbamazepine suspension in humans.

The relative bioavailability of an investigational carbamazepine suspension was studied following rectal administration in human volunteers. Carbamazepine, in doses of approximately 6 mg/kg, was given to nine men. The routes of administration were oral tablet, oral suspension, and rectal suspension. There was no significant difference (p greater than 0.05) in total absorption, maximum serum concentration, and time to achieve maximum serum concentration between the orally-administered tablet and the rectally administered suspension. Orally administered suspension was absorbed more quickly and completely. All volunteers complained of a strong defecatory urge after the suspension was given rectally. The slow absorption after rectal administration precludes the use of this route in status epilepticus; however, it may be a satisfactory alternative for maintenance therapy when administration by the oral route is not possible.