Methadone Pregnancy and Breastfeeding Warnings
Methadone Pregnancy Warnings
This drug should be used during pregnancy only if the benefit clearly outweighs the risk to the fetus. AU TGA pregnancy category: C US FDA pregnancy category: C Comments: -Prolonged use of opioids during pregnancy can result in physical dependence in the neonate; women should be advised of the risk of neonatal abstinence syndrome and ensure that appropriate treatment will be available. -Due to pharmacokinetic differences during pregnancy, the methadone dose may need to be increased or dosing interval decreased in order to achieve therapeutic effectiveness. -This drug should not be used during and immediately prior to labor, when short acting analgesics or other analgesic techniques are more appropriate.
There are no controlled studies of methadone use in pregnant women. An expert review of published data by TERIS (Teratogen Information System) in October 2002, concluded that maternal use during pregnancy as part of a supervised, therapeutic regimen is unlikely to pose a substantial teratogenic risk, but the data is insufficient to state that there is no risk. The relevance of these findings to the use of this drug in chronic pain patients is unclear. Several studies have reported decreased fetal growth in infants born to narcotic-addicted women treated with methadone during all or part of their pregnancy; however this growth deficit does not appear to persist into later childhood. Mild but persistent deficits in performance on psychometric and behavioral tests have been demonstrated. There is conflicting data on whether the risk of sudden infant death syndrome is increased. Animal studies have shown methadone treatment in males can alter reproductive function; specifically this drug has caused a significant regression of sex accessory organs and testes in male mice and rats. Additional animal data have been published indicating that methadone treatment (once a day for three consecutive days) increased embryolethality and neonatal mortality. Examination of uterine contents of methadone-naive female animals bred to methadone-treated male animals indicated that methadone treatment produced an increase in the rate of preimplantation deaths in all postmeiotic states. AU TGA pregnancy category C: Drugs which, owing to their pharmacological effects, have caused or may be suspected of causing, harmful effects on the human fetus or neonate without causing malformations. These effects may be reversible. Accompanying texts should be consulted for further details. US FDA pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.
Methadone Breastfeeding Warnings
Peak methadone levels occur about 4 to 5 hours after an oral dose. A breastfed infant would receive approximately 17.4 mcg/kg/day based on average milk consumption of 150 mL/kg/day; this is approximately 2% to 3% the oral maternal dose. Methadone concentrations from 50 to 570 mcg/L were observed in assays of breast milk from mothers maintained on oral methadone doses of 10 to 80 mg/day. Cases of sedation and respiratory depression in breastfed infants exposed to methadone have been received. There is no information on use of parenteral methadone in breastfeeding, or the safety of high dose methadone typically used for chronic pain management. Pregnant mothers using methadone should be counseled about the benefits and risks of breast-feeding while using methadone. Counseling should include the following information: 1) How to identify respiratory depression and sedation in their babies and when it may be necessary to seek immediate medical care; mothers should be aware that methadone will be transferred to breast milk. 2) The possibility that the baby may experience methadone withdrawal if breast-feeding is discontinued suddenly; mothers should discuss discontinuation of breast-feeding with the baby's healthcare team. 3) Use of other substances of abuse during breast-feeding will expose the baby to additional risks; if other substances of abuse are being used, mothers should not breast-feed.
Use caution Excreted into human milk: Yes Comments: -Women who received methadone maintenance during pregnancy and are stable should be encouraged to breastfeed unless there is another contraindication. -Breastfed infants should be monitored closely for signs of increased sleepiness and breathing difficulties; breastfeeding may decrease, but not eliminate neonatal withdrawal symptoms in infants exposed in utero. -Breastfed infants of mothers using methadone should be weaned gradually to prevent development of withdrawal symptoms.
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