Inhaled opioids for cancer pain relief: A narrative review

Effect of oral naloxone on opioid-induced constipation in methadone maintenance treatment patients, a double-blind, placebo-control, clinical trial

BACKGROUND

Opioid-induced constipation (OIC) is the most prevalent side effect of methadone maintenance therapy (MMT). Naloxone could reduce the OIC.

METHOD

Fifty-six MMT cases (< 75 mg/day methadone, > 3 months) were entered randomly into four groups of a trial. They received placebo or naloxone tablets (0.5, 2, or 4 mg/day) once a day for 2 weeks. They continued their conventional laxative. Their constipation and opiate withdrawal (OWS) were evaluated by the Bristol Stool Form Scale (stool consistency and frequency), Patient Assessment of Constipation Symptoms (PAC-SYM) questionnaire, Constipation Scoring System (CSS), and the Subjective Opiate Withdrawal Scale (SOWS) before starting treatment and at the end of the first and second weeks.

RESULTS

The dose of 4 mg/day naloxone was excluded from the study due to severe OWS. The precipitants of groups had similar ages, methadone dose and duration, laxative use, and constipation scores at the start of the trial. However, 2 mg of naloxone could change the stool consistency (PV = 0.0052) and frequency (P = 0.0133), 0.5 mg/day dose only improved the stool consistency (P = 0.0016). The patients' CSS and PAC-SYM scores were reduced by naloxone after the 1st week of treatment. However, there was no significant difference in the mean score of SOWS at different assessment times and groups. Also, 3 and 4 cases of 0.5 and 2 mg/day groups, respectively, withdrew from the study due to OWS.

CONCLUSION

Oral naloxone at doses of 0.5 and 2 mg/day was significantly more effective than placebo on OIC in MMT. However, the dose of 4 mg induced intolerable OWS.

Towards More Precise Targeting of Inhaled Aerosols to Different Areas of the Respiratory System

Pharmaceutical aerosols play a key role in the treatment of lung disorders, but also systemic diseases, due to their ability to target specific areas of the respiratory system (RS). This article focuses on identifying and clarifying the influence of various factors involved in the generation of aerosol micro- and nanoparticles on their regional distribution and deposition in the RS. Attention is given to the importance of process parameters during the aerosolization of liquids or powders and the role of aerosol flow dynamics in the RS. The interaction of deposited particles with the fluid environment of the lung is also pointed out as an important step in the mass transfer of the drug to the RS surface. The analysis presented highlights the technical aspects of preparing the precursors to ensure that the properties of the aerosol are suitable for a given therapeutic target. Through an analysis of existing technical limitations, selected strategies aimed at enhancing the effectiveness of targeted aerosol delivery to the RS have been identified and presented. These strategies also include the use of smart inhaling devices and systems with built-in AI algorithms.