Naloxone is primarily metabolized in the liver trough dealkylation with reduction of the 6-ketogroup and conjugation with glucuronic acid, and excreted with the urine, in unchanged form and in the form of metabolites [SmPC].
The following pharmacokinetic parameters have been found in term neonates (n=29) with respiratory depression due to administration of opioids to mother within 4 hours before birth, after IV (via umbilical vein) and IM administration with different doses [Moreland 1980]:
|
PK parameters (mean + SD) |
Dose: 35 µg IV n=6 |
Dose: 70 µg IV n=6 |
Dose: 200 µg IM n=17 |
|
Cmax (ng/ml) |
8,2 ± 4,91 |
13,7 ± 4,81 |
18,6 ± 8,02,3 |
|
T1/2 (hr) |
3,53 ± 2,20 |
2,65 ± 1,30 |
NR |
|
Vd (l/kg) |
2,20 ± 1,18 |
1,78 ± 0,73 |
NR |
|
Clplasma (ml/kg/hr) |
564 ± 488 |
576 ± 372 |
NR |
1 Time to reach peak plasma level varied. In five cases peak levels were reached within 5 min. of administration but in the remainder, plasma levels continued to rise for up to 40 min.
2 Time to reach peak plasma levels ranged from 0.5 – 2 hr (mean 1.2 hr).
IM administration resulted in a longer time to peak levels compared to IV doses, possibly due to a drug depot forming at the injection site. The T1/2 after IV administration was two to three times longer than in adults (1 – 1.5 hr), likely due to the reduced ability of neonates to metabolize drugs, as naloxone is primarily eliminated via glucuronidation, which is not yet fully developed in neonates. The relatively long time to reach peak levels observed in some neonates is likely due to naloxone remaining in the umbilical vein after injection, delaying the onset and reducing the magnitude of the pharmacologic effect of naloxone [Moreland 1980].
The following pharmacokinetic parameters have been found in preterm neonates (n=10) with narcotic-induced central nervous system depression or apnea treatment, after IV administration [Stile 1987]:
|
PK parameters mean ± SD (range) |
Dose: 0.04 mg/kg IV n=10 |
|
Cmax (ng/ml) |
18,7 ± 4,2 |
|
T1/2 (min) |
70,8 ± 35,6 (29 – 122) |
|
Vd (l/kg)1 |
3,52 ± 1,20 (2,39 – 6,09) |
|
Cltotal (ml/kg/min) |
39,13 ± 14,53 (24,6 – 74,0) |
1 Vd significantly correlated with birth weight.
The pharmacokinetic parameters in preterm neonates indicate that the T1/2 of naloxone is comparable to that observed in adults (1 – 1.5 hr), in contrast to term neonates, which could be partially attributed to the administration method (via umbilical vein) used in term neonates. The short T1/2 in preterm neonates may indicate that naloxone is metabolized by a different pathway. Although capacity to metabolize substances by glucuronidation and dealkylation is reduced, other reactions such as sulfate and glycine conjugation appear to be present in activities similar to those found in adults [Stile 1987].
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| Opiate overdose, known or suspected (e.g.anesthesia/postoperative analgesia) |
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| Itching as a result of terminal hepatic/renal insufficiency |
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| Complete or partial recovery of the CNS, particulary respiratory depression caused by natural or synthetic opiates |
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| Respiratory depression resulting from administration of opioids to mother less than 4 hours before the birth |
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GFR ≥10 ml/min/1.73m2: Dose adjustment not required.
GFR <10 ml/min/1.73m2: A general recommendation on dose adjustment cannot be provided.
The complete list of all undesirable drug reactions can be found in the national Summary of Product Characteristics (SmPC) – click here
Naloxone, at doses up to 10 mcg/kg, is safe in infants (< 6 months) in terms of not causing unwanted stimulant effects on the opioid receptors or the cardiovascular system. It effectively blocks opioid effects without causing additional changes in heart rate or blood pressure [Fischer 1974].
The complete list of all contra-indications can be found in the national Summary of Product Characteristics (SmPC) – click here
No information available on specific contra indications in children.
The complete list of all warnings and precautions can be found in the national Summary of Product Characteristics (SmPC) – click here
Rapid injection has a strong emetic effect. The effect of naloxone lasts less long than the effect of opoids: longer-term observation is needed because a rebound effect can occur. In such situations, consider administering a continuous infusion [Vila 1979; Karl 1996].
In neonates: ensure proper ventilation first. Naloxone should preferably not be administered to a new-born whose mother is a user of addictive substances due to acute withdrawal symptoms. Can also be administered subcutaneously or intramuscularly if the peripheral circulation of the neonate is sufficient. Monitor for 24 hours after administration.
Administer cautiously to persons with known or suspected dependence on opioids, including neonates of mothers on whom such dependence is known. In such cases, abrupt and complete removal of narcotic effects may result in acute abstinence syndrome (hypertension, cardiac arrhythmias, cardiac arrest, pulmonary edema), this may also occur in the newborn children of such patients [Deshpande 2009].
Excessive dosage may lead to complete removal of analgesia, nervousness and increase in blood pressure. Too rapid a lifting of the effects of opioids may cause nausea, vomiting, sweating, hyperventilation, dizziness, hypertension, tachycardia, tremors, convulsions and cardiac arrest.
In obese children, dosing based on TBW is preferred [Ross 2015; Wells 2020].
The complete list of all interactions can be found in the national Summary of Product Characteristics (SmPC) – click here
This pages provides a list of drugs from the same ATC class for comparison. This does not necessarily mean that these drugs are interchangeable.
| Antidotes | ||
|---|---|---|
| V03AB14 | ||
| Iron chelating agents | ||
|---|---|---|
| V03AC03 | ||
| V03AC02 | ||
| V03AC01 | ||
| Detoxifying agents for antineoplastic treatment | ||
|---|---|---|
| V03AF03 | ||
| V03AF01 | ||
| V03AF07 | ||
| Drugs for treatment of hypoglycemia | ||
|---|---|---|
| V03AH01 | ||
| DETOXIFYING AGENTS FOR ANTINEOPLASTIC TREATMENT | ||
|---|---|---|
| V03AF03 | ||
| V03AF01 | ||
| V03AF07 | ||