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Pharmacokinetics and pharmacodynamics of pentazocine in children
K Hamunen1, K T Olkkola, T Seppälä
1Department of Ophthalmology, University of Helsinki.
Insights
Pentazocine pharmacokinetics in children (4-8 years) undergoing ophthalmic surgery showed adult-like parameters. While it caused temporary decreases in oxygen saturation and ventilation, no assisted ventilation was needed, and analgesia lasted over 2 hours.
Area of Science:
- Pediatric pharmacology
- Anesthesiology
- Pharmacokinetics
Background:
- Pentazocine is an analgesic used in various settings.
- Understanding its pediatric pharmacokinetics and ventilatory effects is crucial for safe administration.
- Ophthalmic surgery in children presents unique challenges for pain management and monitoring.
Purpose of the Study:
- To evaluate the pharmacokinetics of a single intravenous dose of pentazocine in children.
- To assess the ventilatory effects and safety profile of pentazocine in this pediatric population.
- To compare pediatric pharmacokinetic parameters with those of adults.
Main Methods:
- Ten children (4-8 years) received a single intravenous dose of 0.5 mg/kg pentazocine post-ophthalmic surgery.
- Pharmacokinetic parameters (half-life, clearance, volume of distribution) were calculated.
- Ventilatory parameters (rate, oxygen saturation, end-tidal carbon dioxide) and vital signs were monitored.
Main Results:
- Pharmacokinetic parameters were comparable to adult values (e.g., half-life 3.0 +/- 1.5 hr, clearance 21.8 +/- 5.9 ml/min/kg).
- Rapid decreases in ventilatory rate and oxygen saturation, with increased end-tidal carbon dioxide, were observed.
- Four patients experienced oxygen saturation below 90%; one required brief supplemental oxygen. No assisted ventilation was necessary.
Conclusions:
- Pentazocine exhibits adult-like pharmacokinetics in children aged 4-8 years.
- Transient ventilatory depression and decreased oxygen saturation are expected but manageable effects.
- Pentazocine appears to be a safe option for analgesia in pediatric ophthalmic surgery, with a duration of 164 +/- 59 minutes.
Abstract:
Pharmacokinetics and ventilatory effects of a single intravenous dose of 0.5 mg/kg of pentazocine were studied in ten children aged 4 to 8 years after ophthalmic surgery. Elimination half-life (mean +/- S.D.) was 3.0 +/- 1.5 hr and clearance 21.8 +/- 5.9 ml/min./kg. The values for Vc, Vss and V beta were 0.73 +/- 0.21, 4.0 +/- 1.2 and 5.3 +/- 2.1 l/kg, respectively. The pharmacokinetic parameters were similar to those of adults. After administration of pentazocine decrease in ventilatory rate and oxygen saturation and increase in end-tidal carbon dioxide were relatively fast and steep. Oxygen saturation of four patients decreased below 90% and in one patient the decrease did not recover instantly and additional oxygen was given for 2 min. No patient needed assisted ventilation. Only clinically insignificant changes in heart rate and mean arterial pressure were observed. The duration of analgesia was 164 +/- 59 min. No serious side-effects appeared.