Formulation and stability of naltrexone oral liquid for rapid withdrawal from methadone

Efficacy and Safety of Low Dose Naltrexone for Chronic Pain

Naltrexone is a mu-opioid receptor antagonist increasingly used as an analgesic for chronic pain at low doses. This retrospective, observational cohort study was conducted at an academic medical center to evaluate low-dose naltrexone (LDN) efficacy and describe its use in routine clinical practice. Adults receiving LDN, doses <10 mg for ≥1 month, seen at an outpatient pain clinic from January 1, 2014 to April 1, 2022 were included. The primary outcome was change in the Pain, Enjoyment of Life, and General Activity (PEG) score after LDN. Thirty-one patients were included. Median age was 50 years and 71% were female. Median duration of pain at baseline was 5 years. Mean PEG scores were 7.27 ± 1.39 and 6.62 ± 2.04 at baseline and follow-up, respectively. Mean difference was 0.66 (95% CI [0.10-1.21], p = 0.022). Eighty-seven percent (27) of patients discontinued LDN, 52% (16) for lack of benefit, 23% (7) for loss of benefit, 10% (3) for side effects, and 3% (1) for other reasons. Seven (23%) reported side effects. LDN was associated with a statistically significant reduction in PEG in adult chronic pain patients, however the clinical significance is unclear as over 75% of patients discontinued LDN due to lack of benefit.

Developmental Considerations for the Use of Naltrexone in Children and Adolescents

Naltrexone (NTX) is a well-tolerated drug with a wide safety margin and mechanism of action that affords use across a wide variety of indications in adults and children. By antagonizing the opioid reward system, NTX can modulate behaviors that involve compulsivity or impulsivity, such as substance use, obesity, and eating disorders. Evidence regarding the disposition and efficacy of NTX is mainly derived from adult studies of substance use disorders and considerable variability exists. Developmental changes, plausible disease-specific alterations and genetic polymorphisms in NTX disposition, and pharmacodynamic pathways should be taken into consideration when optimizing the use of NTX in the pediatric population. This review highlights the current state of the evidence and gaps in knowledge regarding NTX to facilitate evidence-based pharmacotherapy of mental health conditions, for which few pharmacologic options exist.

Low-Dose Naltrexone-Induced Remission in Hailey-Hailey Disease Maintained in Remission with Topical Combination of Ketamine and Diphenhydramine

Recent anecdotal evidence suggests that oral low-dose naltrexone (LDN) is effective for Hailey–Hailey disease (HHD) but suffers the limitation of immediate relapse following cessation of the medication. With lack of safety data on long-term administration of LDN, we explored the utility of a topical diphenhydramine/ketamine (DK) cream in maintaining the remission achieved with LDN. A 42-year-old male with treatment-refractory HHD remitted with 5 mg naltrexone/day but relapsed on stopping the drug. Symptoms abated after restarting LDN. The impact of regular twice-a-day application of a specially formulated DK cream containing diphenhydramine (2% w/w) and ketamine (1% w/w) over the affected areas on maintenance of remission was explored till the next relapse. Our approach enabled dose reduction of naltrexone to 3 mg/day without loss of treatment benefit. After 3-month overlap of naltrexone and DK cream, withdrawal of naltrexone maintained remission with only the topical regime with no adverse effects till 4 months of follow-up. The use of topical agents with anti-inflammatory, antipruritic, antinociceptive, and naltrexone-mimicking properties merits exploration as an option to provide short but significant period of naltrexone-free maintenance of remission to patients with HHD.

Pediatrics Efficacy and Safety of Naltrexone Use in Pediatric Patients with Autistic Disorder

Objective:

To review the efficacy and safety of naltrexone in pediatric patients with autistic disorder (AD).

Data Sources:

Using the terms pediatric, child, naltrexone, autism, and autistic disorder, a literature search was performed using MEDLINE (1966–May 18, 2006) and the International Pharmaceutical Abstracts (1971–May 18, 2006) database. The references of these articles were scanned for additional relevant literature.

Study Selection and Data Extraction:

All articles describing or evaluating the efficacy and/or safety of naltrexone in pediatric patients with AD were included in this review. Three case reports, 8 case series, and 14 clinical studies were identified as pertinent.

Data Synthesis:

Naltrexone has been used most commonly at doses ranging from 0.5 to 2 mg/kg/day and found to be predominantly effective in decreasing self-injurious behavior. Naltrexone may also attenuate hyperactivity, agitation, irritability, temper tantrums, social withdrawal, and stereotyped behaviors. Patients may also exhibit improved attention and eye contact. Transient sedation was the most commonly reported adverse event. Small sample size, short duration, and inconsistent evaluative methods characterize the available research.

Conclusions:

A child affected by AD may benefit from a trial of naltrexone therapy, particularly if the child exhibits self-injurious behavior and other attempted therapies have failed. Serious adverse effects have not been reported in short-term studies.

Characterization of a potential medium for ‘biorelevant’ in vitro release testing of a naltrexone implant, employing a validated stability-indicating HPLC method

A variety of factors have been recognized that influence media optimization for drug release studies of implant dosage forms. Of primary importance is selection of a medium that physiologically mimics the milieu at the site of administration (a condition termed 'biorelevance'). We describe in this paper, the characterization of Hanks' balanced salts solution, with necessary modification, for application as a 'biorelevant' medium for in vitro release studies of a biodegradable, subcutaneous implant of naltrexone. A detailed investigation of changes in pH, osmolality and ultraviolet (UV) spectrum as a function of time and temperature was conducted. Variation in the parameters evaluated was found to be within acceptable limits. Validation of a simple and selective, high performance liquid chromatography (HPLC) assay method for naltrexone was carried out to evaluate stability. The calibration curves were linear from 0.16 to 20.00 microg ml(-1). Imprecision and inaccuracy were less than 2% and no interference was observed from degradation peaks. Stability studies of naltrexone indicated the media should be replaced every 7-8 days for real-time testing. This was applied to an investigation of in vitro drug release. The method has been proven to be suitable for investigation of naltrexone released from the implant.