Intranasal therapy with opioids for children and adolescents with cancer: results from clinical studies

Opioids are essential for the treatment of pain, which is a serious symptom for children and adolescents affected by cancer. Intranasal opioids may be very useful for the treatment of breakthrough pain in children and adolescents with cancer, for their little invasiveness, ease of administration, rapid onset of action, and high bioavailability. Intranasal drug delivery may be influenced by anatomical and physiological factors (nasal mucosa absorption area, mucociliary clearance, enzymatic activity, anatomical anomalies, chronic or inflammatory alterations of nasal mucosa), drug-related factors (molecular weight, solubility), and delivery device. Fentanyl is a lipophilic opioid commonly proposed for intranasal use among pediatric patients, but no studies have been conducted yet about intranasal use of other available opioids for management of pediatric cancer pain. In this review, we analyze several elements which may influence absorption of intranasal opioids in children and adolescents, with a focus on pharmacokinetics and therapeutic aspects of each opioid currently available for intranasal use.