Characterizing Baclofen Withdrawal: A National Survey of Physician Experience.

OBJECTIVE: We studied physicians' opinions and experiences concerning clinical concerns, perceived severity, occurrence, and management of baclofen withdrawal due to abrupt discontinuation. METHODS: A nationwide 26-question electronic survey was distributed via e-mail to physicians (N = 952) representing varying specialties who manage spasticity with baclofen. A total of 110 physicians provided responses to the survey (response rate = 11.6%). Results were evaluated using descriptive statistics. RESULTS: Withdrawal from both oral and intrathecal (IT) baclofen was recognized as a significant concern and was observed by most respondents. However, approximately 75% and 35% of respondents or their clinic sites lack established management protocols for managing anticipated interruption of oral or IT baclofen, respectively. CONCLUSIONS: These findings highlight the need for further research on and the development of guidelines for the prevention and treatment of baclofen withdrawal. The results of this survey, along with a systematic literature review and multidisciplinary stakeholder input, may be helpful in establishing guidelines for the treatment and prevention of baclofen withdrawal.

A Randomized Dose Escalation Study of Intravenous Baclofen in Healthy Volunteers: Clinical Tolerance and Pharmacokinetics.

BACKGROUND: Abrupt discontinuation of baclofen can result in a potentially severe withdrawal syndrome. The current treatment for baclofen withdrawal is inadequate, resulting in a critical need to develop an alternative method to prevent or treat this withdrawal syndrome. OBJECTIVE: To evaluate the safety profile and pharmacokinetics of oral (PO) and investigational intravenous (IV) baclofen formulations at clinically relevant doses. DESIGN: Randomized, open-label, dose-escalation, crossover study. SETTING: Contract Research Organization (CRO). METHODS: Three cohorts of 12 healthy adults received single doses of PO baclofen (10 mg, 15 mg or 20 mg) and 10-minute infusions of IV baclofen (7.5 mg, 11.5 mg, or 15 mg) with a minimum 48-hour wash-out period. The third cohort also received a 60-minute infusion of 15 mg IV baclofen after an additional 48-hour wash-out period. MAIN OUTCOME MEASURES: Subjects were observed in a CRO for 24 hours after each dose of baclofen, and were assessed for nystagmus, ataxia, and sedation. Blood samples were collected from 0 to 24 hours and analyzed for baclofen concentration using high-performance liquid chromatography-mass spectroscopy. Noncompartmental pharmacokinetic analyses were performed. Dose linearity and proportionality was assessed using 2-way repeated-measures analysis of variance and a power model analysis. RESULTS: None of the PO or IV doses resulted in significant sedation compared to baseline. All subjects could perform tandem gait after each baclofen dose. The most common side effect, transient mild nystagmus, was noted in 4 of 36 and in 13 of 36 subjects after PO and IV administration, respectively. This was likely related to increased maximum concentrations (Cmax). After the 20 mg PO and 15 mg IV doses, mean Cmax levels were 255 and 722 ng/mL and half-lives were 5.24 and 5.79 hours for PO and IV baclofen, respectively. The mean oral bioavailability for the 20-mg PO dose was approximately 80%. CONCLUSIONS: All PO and IV doses of baclofen were well tolerated clinically. The 80% bioavailability suggests that a 20% reduction in IV dose will produce comparable total drug exposures to that of the PO dose. When PO therapy is interrupted, bridging with IV baclofen may be feasible. LEVEL OF EVIDENCE: II.

A pilot study assessing pharmacokinetics and tolerability of oral and intravenous baclofen in healthy adult volunteers.

Our objective was to characterize baclofen pharmacokinetics and safety given orally and intravenously. Twelve healthy subjects were enrolled in a randomized, open-label, crossover study and received single doses of baclofen: 3 or 5 mg given intravenously and 5 or 10 mg taken orally with a 48-hour washout. Blood samples for baclofen analysis were collected pre-dose and at regular intervals up to 24 hours post-dose. Clinical response was assessed by sedation scores, ataxia, and nystagmus. Mean absolute bioavailability of oral baclofen was 74%. Dose-adjusted areas under the curve between the oral and intravenous arms were statistically different (P = .0024), whereas area under the curve variability was similar (coefficient of variation: 18%-24%). Adverse effects were mild in severity and not related to either dose or route of administration. Three- and 5-mg intravenous doses of baclofen were well tolerated. Seventy-four percent oral bioavailability indicates that smaller doses of intravenous baclofen are needed to attain comparable total drug exposures.

Pharmacokinetics and pharmacodynamics of intravenous baclofen in dogs: a preliminary study.

UNLABELLED: Abrupt discontinuation of baclofen therapy is associated with a clinically serious withdrawal syndrome. Current treatment modalities are often ineffective. Intravenous (IV) baclofen is a potential method for preventing or treating baclofen withdrawal syndrome. OBJECTIVES: To complete a preliminary study of IV baclofen in dogs. METHODS: Single bolus IV doses (0.5, 2 and 3 mg/kg) as well as multiple dose regimens were evaluated. Sedation and clinical tolerability was assessed by modified Glasgow Coma Scale and Discomfort and Behaviour Scale. KEY FINDINGS: Baclofen concentration-time profiles following single IV boluses were best fit by a two-compartment model which was used to predict plasma concentrations for the multiple dose regimens. The mean distribution and elimination half-lives were 11 min and 222 min, respectively. Maximum clinical effect did not occur until approximately 120 min. The discomfort score increased proportionately with increased single IV bolus doses. Multiple dose regimens resulted in greater than proportionate discomfort scores based on total dose and were generally not as well tolerated. CONCLUSIONS: If projected for human use, our data suggests that initial IV baclofen doses will need to be reduced by approximately one-third of the usual oral dose, and clinicians should observe patients for several hours before administering subsequent doses.

A pilot study assessing the bioavailability and pharmacokinetics of diazepam after intranasal and intravenous administration in healthy volunteers.

Diazepam rectal gel (Diastat(®)) is the only FDA-approved product indicated for acute repetitive seizures. Despite its proven efficacy, most older children and adults object to this route of administration. As a result, many patients do not realize the benefit of a therapy that can improve outcomes and decrease healthcare costs. Intranasal administration of benzodiazepines offers a potential alternative. The primary objective of this study was to compare the bioavailability and pharmacokinetics of two novel intranasal (IN) diazepam (DZP) formulations versus intravenous (IV) administration in healthy volunteers. Twenty-four healthy volunteers were randomized into an open-label, three-way crossover study. 10mg doses of two investigational intranasal DZP formulations (solution, suspension) and a 5mg IV dose of commercially available DZP injectable, USP were given. A two-week washout period separated treatments. Plasma samples for DZP analysis were collected pre-dose and at regular intervals up to 240 h post-dose. DZP concentration-time data were analyzed using a non-compartmental pharmacokinetics approach. Exposure following administration of DZP IN solution (absolute bioavailability - 97%) was greater than the IN suspension (absolute bioavailability - 67%). Mean Cmaxvalues for the suspension and solution formulations were 221 ng/mL and 272 ng/mL, respectively. Median time to maximum concentration (Tmax) was 1h and 1.5h for suspension and solution formulation, respectively. Both investigational intranasal formulations were well tolerated. The results of this pilot study indicate that development of an intranasal diazepam formulation with high bioavailability, reasonable variability, and good tolerability is feasible.

Intravenous topiramate: safety and pharmacokinetics following a single dose in patients with epilepsy or migraines taking oral topiramate.

PURPOSE: Although topiramate is widely prescribed for epilepsy and migraine, there is no intravenous product. We have developed an injectable topiramate formulation in which the drug is solubilized in a cyclodextrin matrix, Captisol(®) (Ligand Pharmaceuticals, Inc., La Jolla, CA). Our long-term goal is to evaluate intravenous topiramate for the treatment of neonatal seizures. Prior to studies in newborns, we carried out an investigation of injectable topiramate's safety and pharmacokinetics in adult patients. METHODS: Twenty adult volunteers with epilepsy or migraine on stable, on maintenance topiramate therapy were given 25 mg of a stable-labeled intravenous topiramate over 10 min, followed by their usual oral doses. Vital signs were taken, electrocardiography studies (ECGs) were recorded, and the infusion sites were periodically examined prior to and up to 24 h after dosing. Blood samples were collected prior to administration and serially for 96 h thereafter. Plasma concentrations of both stable-labeled and regular topiramate were measured using liquid chromatography-mass spectrometry (LC-MS). Concentration-time data were analyzed using a noncompartmental approach with WinNonlin 5.2 (Pharsight Corporation, Mountain View, CA, U.S.A.). KEY FINDINGS: Seven patients experienced one or more of the following minor adverse events including nausea and vomiting (1), tingling around the lips (1), paresthesia in the arms and legs (1), and a mild vasovagal response with intravenous catheter placement (1). Included in the adverse events were four patients with epilepsy who had seizures consistent with their histories. There were no changes in heart rate, blood pressure, or ECG results, and there were no infusion site reactions. Pharmacokinetic parameters (mean ± standard deviation [SD]) determined following the intravenous dose included absolute bioavailability: 110 ± 16%, distribution volume: 0.79 ± 0.22 L/kg, clearance: 2.03 ± 1.07 L/h, and elimination half-life: 27.6 ± 9.7 h. Distribution volume, half-life, and clearance were significantly altered by enzyme-inducing drugs. SIGNIFICANCE: A single 25-mg dose of intravenous topiramate caused minimal infusion site or systemic adverse effects in patients taking oral topiramate. Pharmacokinetic results show that oral topiramate is completely absorbed and that its steady-state elimination half-life is longer than previously assumed, which permits once or twice daily dosing even in the presence of enzyme-inducing drugs. The information from this study can inform the design of subsequent studies in adults, older children, and newborns, including controlled clinical trials intended to determine the efficacy and safety of intravenous topiramate for neonatal seizures.

Intravenous topiramate: comparison of pharmacokinetics and safety with the oral formulation in healthy volunteers.

PURPOSE: Although oral topiramate (TPM) products are widely prescribed for migraines and epilepsy, injectable TPM is not available for human use. We have developed a solubilized TPM formulation using a cyclodextrin matrix, Captisol with the long-term goal of evaluating its safety and efficacy in neonatal seizures. This study in healthy adult volunteers was performed as required by the U.S. Food and Drug Administration (FDA) to demonstrate the pharmacokinetics and safety prior to initiation of studies involving children. This study allowed investigation of absolute bioavailability, absolute clearance, and distribution volume of TPM, information that could not be obtained without using an intravenous TPM formulation. METHODS: This study was an open-label, two-way crossover of oral and intravenous TPM in 12 healthy adult volunteers. Initially two subjects received 50 mg, intravenously and orally. Following evidence of safety in the first two subjects, 10 individuals received 100 mg doses of intravenous and oral TPM randomly sequenced 2 weeks apart. Blood samples were taken just prior to drug administration and at intervals up to 120 h afterwards. TPM was measured using a validated liquid chromatography-mass spectrometry method. Concentration-time data were analyzed using a noncompartmental approach with WinNonlin 5.2. KEY FINDINGS: All subjects completed the study. The mean (±standard deviation) absolute oral bioavailability was 109% (±10.8%). For intravenous and oral TPM the mean distribution volumes were 1.06 L/kg (±0.29) and 0.94 L/kg (±0.24). Clearances were 1.33 L/h (±0.26) and 1.22 L/h (±0.26). The half-life values were 42.3 h (±6.2) and 41.2 h (±7.5). No changes in heart rate, blood pressure, electrocardiography, or infusion site reactions were observed. Mild central nervous system cognitive adverse events and ataxia occurred between dosing and 2 h post dose with both intravenous and oral administration. With intravenous TPM, these adverse effects occurred as early as during the 15-min intravenous infusion. SIGNIFICANCE: In healthy adults, oral TPM is bioequivalent to intravenous TPM, and infusion of 50-100 mg over 15 min is safe. Neurologic effects occurred during the infusion, demonstrating that TPM rapidly diffuses into the brain, which supports its evaluation for neonatal seizures. Results from this pilot study will inform the design of subsequent studies in children and newborns, including controlled clinical trials intended to assess the efficacy and safety of intravenous TPM for neonatal seizures. In addition, our results provide support for the further development of intravenous TPM as bridge therapy for older children and adults in whom oral TPM therapy is interrupted.

Clinical tolerance and toxicity of intravenous baclofen: a pilot study in a canine model.

OBJECTIVE: Assess safety and tolerance of intravenous (IV) baclofen using a dog model. DESIGN: Prospective pharmacokinetic study involving 6 adult dogs. Two dogs received baclofen 10 mg oral and IV bolus doses. Subsequent 4 dogs were given IV boluses of 0.5, 1.0 and 1.5 mg/kg followed by constant infusion of baclofen (rates of 0.1, 0.2 and 0.4 mg/kg/hour). Also, dogs were given single IV 2 and 3 mg /kg bolus doses. Outcome measures included clinical observation scales and baclofen levels. RESULTS: Oral bioavailability was 0.66 and 0.69 in 2 dogs. Following IV baclofen, terminal phase half-lives were 3.3 and 3.6 hours. Single bolus doses of 2 and 3 mg/kg caused mild to moderate clinical changes which were delayed at least 2 hours after peak blood levels. Boluses of 0.5 and 1.0 mg/kg with constant infusion between boluses were tolerated, however within 30 minutes of beginning constant infusion of 0.2 mg/kg/hr after the second bolus (1.0 mg/kg), dogs showed progressive sedation and ataxia. Clinical improvement occurred within 7 hours of stopping baclofen. Dogs appeared normal by the next morning. CONCLUSIONS: IV baclofen bolus doses of 0.5 to 3 mg/kg were well tolerated. Maximum clinical effect was delayed for at least 2 hours after peak plasma levels.

Survival of individuals with cerebral palsy receiving continuous intrathecal baclofen treatment: a matched-cohort study.

AIM: To determine whether intrathecal baclofen (ITB) changes mortality risk in persons with cerebral palsy (CP). METHOD: Records were reviewed for all persons with CP who were managed with ITB for hypertonicity at a specialty hospital in Minnesota between May 1993 and August 2007. A comparison cohort was randomly selected from clients of the California Department of Developmental Services who were initially evaluated between 1987 and 1990 and were matched to those with ITB for age, sex, Gross Motor Function Classification System (GMFCS) level, presence or absence of epilepsy, and feeding-tube use. Survival probabilities were estimated using the Kaplan-Meier method, and differences were tested via log-rank. RESULTS: Three hundred and fifty-nine persons with CP (202 males, 157 females) receiving ITB for hypertonicity (mean age 12y 8mo, SD 7y 9mo, range 3y 1mo to 39y 9mo) were matched to 349 persons without ITB pumps (195 males, 154 females; mean age 12y 7mo, SD 8y 4mo, range 2y 7mo to 40y). The proportion of patients at different GMFCS levels in the ITB and in the non-ITB cohorts, respectively, was as follows: level II 3% and 3%, level III 16% and 16%, level IV 38% and 37%, and level V 43% and 44%. Survival at 8 years of follow-up was 92% (SD 1.9%) in the ITB cohort and 82% (SD 2.4%) in the non-ITB cohort (p<0.001). After adjustment to account for recent trends in improved survival in CP, 8-year survival in the non-ITB cohort was 88%, which was not significantly different from the ITB cohort (p=0.073). INTERPRETATION: ITB therapy does not increase mortality in individuals with CP and may suggest an increase in life expectancy.

Pediatric injury prevention: methods of booster seat education.

Sixty elementary schools in Minneapolis were asked to participate in a study to evaluate the most effective education method to increase booster seat knowledge and use in kindergarten-age children. School personnel selected one of the following interventions: (1) written information, (2) parent education class and a free booster seat, or (3) student education and a free booster seat. Twenty schools participated, with 132 parents completing the telephone interview 3 to 6 months post-survey. Providing instructions to parent groups and teaching children in the classroom, along with providing an incentive booster seat, was shown to increase booster seat use. Providing information only was found to be ineffective. Pediatric and school nurses should focus their injury prevention efforts beyond written materials. Results indicate that presentations for children and their parents, along with incentives, can result in changes in behavior.

Bioavailability and tolerability of intranasal diazepam in healthy adult volunteers.

Intranasal therapy has been proposed as an alternative for the management of seizure emergencies. The bioavailability, dose proportionality and tolerability of a supersaturated intranasal formulation of diazepam (DZP) solubilized in a glycofurol-water cosolvent system was investigated. Eight healthy volunteers were randomized into a single-blind, three-way crossover study to compare 5 and 10mg intranasal DZP doses of the investigational formulation with a 5mg dose of a DZP solution (DZP injectable, 5mg/mL) administered intravenously. Treatments were separated by a two-week washout period. Plasma samples for DZP analysis were collected pre-dose and at regular intervals up to 48h post-dose and assayed by HPLC. Visual analog scales (VAS) were used to assess tolerability (1-tolerable; 10-extremely intolerable) and pain (1-no pain; 4-extreme pain) at predefined time points. Following the 5 and 10mg doses, the median t(max) were 20 and 30min and the mean C(max) were 134.3+/-62 and 247.6+/-61ng/mL. Estimated bioavailability was 75% for both doses. Pain scores of 2 and 2.3 were observed following the 5 and 10mg doses; tolerability scores were 4.4 and 4.7. Pain and tolerability scores returned to baseline within 10h. Our formulation provided reasonable bioavailability, but was not well tolerated.

Complex dosing schedules for continuous intrathecal baclofen infusion.

The objective of the present study was to understand the clinical reasons for changes from simple continuous to complex (flex) dosing for tone reduction in individuals receiving intrathecal baclofen. Methodology was a retrospective chart review study of 164 individuals (95 male, 69 female) at a multi-specialty children's hospital who were followed for at least 1 year for intrathecal baclofen management. Eighty-two persons were in the simple continuous only group and 82 also were on complex schedules at least once during the follow-up period. Mean age at most recent follow-up was 18 years and 0 months (median, 15 years and 8 months; standard deviation, 8 years and 0 months; range, 6-45). The top three clinical reasons for switching dosing method were to (1) optimize intrathecal baclofen effect, (2) treat predictable daily tone variation, and (3) manage signs and symptoms of intrathecal baclofen withdrawal or underdelivery. In both groups, 90% of individuals had cerebral palsy, and mean baseline leg Ashworth scores were the same in both groups (mean, 3.7; standard deviation, 0.7). Mean total daily dose at chart review was higher in complex dosing (429.3 vs 211.9 microg/day), as was mean follow-up time (4.8 vs 3.9 years). Case examples are presented.

Relative bioavailability, metabolism and tolerability of rectally administered oxcarbazepine suspension.

BACKGROUND AND OBJECTIVE: Maintenance of effective drug concentrations is essential for adequate treatment of epilepsy. Some antiepileptic drugs can be successfully administered rectally when the oral route of administration is temporarily unavailable. Oxcarbazepine is a newer antiepileptic drug that is rapidly converted to a monohydroxy derivative, the active compound. This study aimed to characterise the bioavailability, metabolism and tolerability of rectally administered oxcarbazepine suspension using a randomised, crossover design in ten healthy volunteers. METHODS: Two subjects received 300 mg doses of oxcarbazepine suspension via rectal and oral routes and eight received 450 mg doses. A washout period of at least 2 weeks elapsed between doses. The rectal dose was diluted 1:1 with water. Blood samples and urine were collected for 72 hours post-dose. Adverse effects were assessed at each blood collection time-point using a self-administered questionnaire. Plasma was assayed for oxcarbazepine and monohydroxy derivative; urine was assayed for monohydroxy derivative and monohydroxy derivative-glucuronide. Maximum plasma concentration (C(max)) and time to reach C(max) (t(max)) were obtained directly from the plasma concentration-time curves. The areas under the concentration-time curve (AUCs) were determined via non-compartmental analysis. Relative bioavailability was calculated and the C(max) and AUCs were compared using Wilcoxon signed-rank tests. RESULTS: Mean relative bioavailability calculated from plasma AUCs was 8.3% (SD 5.5%) for the monohydroxy derivative and 10.8% (SD 7.3%) for oxcarbazepine. Oxcarbazepine and monohydroxy derivative C(max) and AUC values were significantly lower following rectal administration (p < 0.01). The total amount of monohydroxy derivative excreted in the urine following rectal administration was 10 +/- 5% of the amount excreted following oral administration. Oral absorption was consistent with previous studies. The most common adverse effects were headache and fatigue with no discernible differences between routes. CONCLUSIONS: Monohydroxy derivative bioavailability following rectal administration of oxcarbazepine suspension is significantly lower than following oral administration, most likely because of poor oxcarbazepine water solubility. It is unlikely that adequate monohydroxy derivative concentrations can be achieved with rectal administration of diluted oxcarbazepine suspension.

GMFM 1 year after continuous intrathecal baclofen infusion.

The purpose of this study was to assess whether there is an improvement in motor function in persons with cerebral palsy (CP) who have had a reduction of muscle tone by continuous intrathecal baclofen infusion. This was a prospective, open label, non-blinded case series without a control group, conducted at multiple centres. There were 31 subjects, aged 4-29 years. All had a pre-treatment mean lower extremity Ashworth scores of >or= 3 and a significant reduction in tone after a bolus injection of intrathecal baclofen (ITB) and received an implanted pump for continuous delivery of ITB. Motor function was assessed by the Gross Motor Function Measure (GMFM) prior to and 1 year following pump implantation. Significant improvement (p < 0.05) in mean GMFM scores was seen in subjects < 8 years (mean change 4.1) and in those from 8-18 years (mean change 3.7) and in subjects with CP Classes 2 and 5 (mean changes 6.2 and 2.9). There was a statistically significant decrease (p < 0.05) in Ashworth scores in CP classes 2-5. Subjects or their caregivers that completed a survey about perceived changes stated that motor control, positioning and endurance improved.

Hip status in cerebral palsy after one year of continuous intrathecal baclofen infusion.

The purpose of this study was to assess whether reduction of muscle tone by continuous intrathecal baclofen infusion affects the progression of hip subluxation in persons with cerebral palsy. This prospective, open-label, case series was conducted at multiple specialty referral centers. There were 33 subjects, ages 4 to 31 years. All had a pretreatment lower extremity Ashworth score of >/=3; all subjects had a significant reduction in tone after a bolus injection of intrathecal baclofen and received an implanted pump for continuous delivery of intrathecal baclofen. Subjects had hip x-rays before and 1 year after pump implantation. The primary outcome measure was change in absolute hip migration percentage. One third of the hips had an increase of absolute migration percentage of 5% or more; 12% of the hips had a decrease of migration percentage of 5% or more. Change of migration percentage class was used as a second outcome criterion. 90.9% of hips manifested no deterioration or had improvement of their migration percentage class during the year of intrathecal baclofen therapy. The observed changes were not associated with the subject's age or the severity of cerebral palsy.

Rapid infusion of sodium valproate in acutely ill children.

The purpose of this study was to investigate the clinical safety of sodium valproate and total and unbound valproic acid plasma concentrations after rapid infusion in hospitalized, acutely ill children. Four children (5-15 years) completed the study. Sodium valproate doses (8.3-15.4 mg/kg) were administered in

Relative bioavailability of topiramate administered rectally.

OBJECTIVE: To determine the relative bioavailability and tolerability of a topiramate (TPM) suspension after rectal administration. DESIGN/METHOD: Seven healthy men and five healthy non-pregnant women were enrolled. A 100 or 200 mg tablet of TPM was given orally and a 200 mg dose was given rectally in a randomized, open-label, crossover study with at least a 2-week washout period between doses. Plasma samples were collected prior to dosing and the following times after each dose: 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, 16, 24, 48, 72, and 96 h. Relative bioavailability was determined by calculating the ratio of the dose-normalized area under the curve (AUC/D) for the rectal and oral doses. RESULTS: Ten subjects completed the study. Two of the first seven subjects who received a 200 mg initial oral dose, withdrew because of side effects. The remaining subjects received a 100 mg oral dose. Three subjects received a 200 mg dose orally and rectally, and seven subjects received 100 mg orally and 200mg rectally. The average AUC/D was 0.72+/-0.18 h/l for the rectal dose and 0.76+/-0.20 h/l for the oral dose. The relative bioavailability (n=10) for TPM administered rectally was 0.95+/-0.17 with a range of 0.68-1.2. There were no statistically significant differences between the oral or rectal pharmacokinetic parameters. CONCLUSIONS: In healthy adults, rectally administered TPM is absorbed to a similar extent as the oral dosage form. Rectal administration is an acceptable route of administration for TPM, when the oral route is temporarily unavailable.

Administration of Carbatrol to children with feeding tubes.

An extended-release formulation of carbamazepine (Carbatrol) might be suited for administration through feeding tubes because the capsules can be pulled apart to release the small granules. However, after encouraging several parents to use the new formulation, we were informed that the drug occluded some tubes. The purpose of this study was to determine if a protocol could be developed to administer Carbatrol without occlusion of the tubes. We administered the granules through feeding tubes to six children. Ten milliliters of water was used to flush the tube before administration. One capsule of Carbatrol was added to the 15 mL of liquid followed by an additional 10 mL water flush. For four children, 152 of 154 doses were administered without difficulty; however, two children were withdrawn from the study because of frequent tube occlusions. No adverse experiences occurred other than tube occlusion. The two children with frequent tube occlusions had long-standing problems with constipation or rigidity, which may have increased intra-abdominal pressure and slowed the rate of administration. We conclude that the use of Carbatrol granules for children with feeding tubes can be useful. However, some children are prone to frequent occlusion.