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Drugs & lactation

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Drugs and Lactation
Aboubakr Elnashar

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Drugs & lactation

  1. 1. Drugs&Lactation Prof Aboubakr Elnashar Benha University Hospital, Egypt Email: elnashar53@hotmail.com Aboubakr Elnashar
  2. 2. •Breast-feeding has many benefits. •Potential harm to the nursing infant from maternal drugs is a reason to discontinue breast-feeding. •Physicians receive little education about breast- feeding and even less training on the effects of maternal drugs on the nursing infant. Aboubakr Elnashar
  3. 3. •The mammary tissue in the breast is composed of clusters of milk-producing alveolar cells surrounding a central lumen. Aboubakr Elnashar
  4. 4. Aboubakr Elnashar
  5. 5. A ducts B lobules C dilated section of duct to hold milk D nipple E fat F pectoralis major muscle G chest wall/rib cage Enlargement: A normal duct cells B basement membrane C lumen (center of duct) Aboubakr Elnashar
  6. 6. The effect of drugs on the nursing infant depends on 1.Transfer of drug into Breast Milk 2.The amount of breast milk consumed by the infant. 3. The pharmacologic activity of the drug: absorption, distribution, metabolism and elimination by the infant. 4. Condition of the infant: Greater precaution for infants premature or compromised or in the first week of life than for older, healthy infants. Aboubakr Elnashar
  7. 7. Transfer of dugs into Breast Milk •Nearly all drugs transfer into breast milk to some extent. •Notable exceptions are heparin and insulin {too large to cross biological membranes}. •Drug transfer from maternal plasma to milk is, with rare exceptions, by passive diffusion across biological membranes. Aboubakr Elnashar
  8. 8. • Factors affecting drug transfer I. The maternal serum drug concentration. Aboubakr Elnashar
  9. 9. II. Drugs: protein binding, lipid solubility, molecular weight and ionization •Transfer is greatest low protein binding high lipid solubility. Small molecular weight weakly basic drugs Aboubakr Elnashar
  10. 10. III. Milk composition Milk at the end of a feed (hindmilk) contains considerably more fat than foremilk and may concentrate fat-soluble drugs. Aboubakr Elnashar
  11. 11. IV. Age of infant: •In the early postpartum period, large gaps between the mammary alveolar cells allow many dugs to pass. These gaps close by the 2nd week of lactation. •Premature babies & infants less than 1 month have a different capacity to absorb and excrete drugs than older infants. Thus, extra caution is needed for these infants. Aboubakr Elnashar
  12. 12. Calculation of infant exposure to drugs The infant dose (mg/kg) I. D infant (mg/kg/day)= C maternal (mg/L) x M/PAUC x V infant (L/kg/day) •Cmaternal= maternal plasma concentration • M/PAUC ratio = milk to plasma concentration ratio area under curve. •Vinfant= volume of milk ingested II. As a percentage of the maternal dose (mg/kg). The volume of milk ingested by infants is commonly estimated as 0.15 L/kg/day. An arbitrary cut-off of 10% has been selected as a guide to the safe use of drugs during lactation. Aboubakr Elnashar
  13. 13. WHO classification of drugs during breastfeeding (2002) 1. Compatible with breastfeeding 2. Compatible with breastfeeding {occasional mild side effects} Monitor infant for side effects 3. Avoid if possible. {significant side effects} Monitor infant for side-effects 4. Avoid if possible. {May inhibit lactation}. Monitor for amount of milk 5. Contraindicated {dangerous side effects} Aboubakr Elnashar
  14. 14. WHO Classification DRUGS during BREASTFEEDING (2002) 1. Compatible with breastfeeding There are no known or theoretical contraindications for their use, and it is considered safe for the mother to take the drug and continue to breastfeed. Aboubakr Elnashar
  15. 15. 2. Compatible with breastfeeding {Occasional mild side-effects} Monitor infant for side-effects •If side-effects: stop the drug, and find an alternative. If the mother cannot stop the drug, she may need to stop breastfeeding and feed her baby artificially until her treatment is completed. Aboubakr Elnashar
  16. 16. 3. Avoid if possible {significant side effects} Monitor infant for side-effect Aboubakr Elnashar
  17. 17. Psychotropic drugs, anti-anxiety, antidepressant, and antipsychotic , when given to nursing mothers for long periods could alter short-term and long-term central nervous system function. Aboubakr Elnashar
  18. 18. 4. Avoid if possible {May inhibit lactation} However, if a mother has to take one of these drugs for a short period, she does not need to give artificial milk to her baby. She can off set the possible decrease in milk production by encouraging her baby to suckle more frequently. Estrogen COC Ergometrin Thiazides Aboubakr Elnashar
  19. 19. 5. Contraindicated {Dangerous side-effects}. If they are essential: stop breast feeding until treatment is completed. If treatment is prolonged, she may need to stop breastfeeding altogether. There are very few drugs in this category apart from anticancer drugs and radioactive substances. Aboubakr Elnashar
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  22. 22. lithium (infant dose as high as 80% of the weight- adjusted maternal dose) and amiodarone (infant dose up to 50%) should be avoided due to high infant exposure and potential for significant toxicity. For drugs with greater inherent toxicity such as cytotoxic agents, ergotamine, gold salts, immunosuppressives and isotretinoin, the cut-off of 10% is too high and breastfeeding is contraindicated. Aboubakr Elnashar
  23. 23. AMERICAN ACADEMY OF PEDIATRICS (2001) Aboubakr Elnashar
  24. 24. Before prescribing drugs to lactating women 1. Is drug really necessary? If drugs are required, consultation between the pediatrician and the mother’s physician can be most useful in determining what options to choose. Aboubakr Elnashar
  25. 25. 2. The safest drug should be chosen e.g. acetaminophen rather than aspirin for analgesia. 3. If there is a possibility that a drug may present a risk to the infant, consideration should be given to measurement of blood concentrations in the nursing infant. 4. Drug exposure to the nursing infant may be minimized Aboubakr Elnashar
  26. 26. Minimizing Potential Risk to Nursing Infants from Maternal Medications General considerations •Use topical therapy when possible. •Drugs that are safe for the nursing infant’s age are generally safe for the breast-feeding mother. •Drugs that are safe in pregnancy are not always safe in breast-feeding mothers {nursing infant must independently metabolize and excrete the medication}. Aboubakr Elnashar
  27. 27. Medication selection •Choose medications with the shortest half-life and highest protein-binding ability. •Choose medications that are well-studied in infants. •Choose medications with the poorest oral absorption. •Choose medications with the lowest lipid solubility. Aboubakr Elnashar
  28. 28. Medication dosing •Administer single daily-dose drugs just before the longest sleep interval for the infant, usually after the bed-time feeding. •Breast-feed infant immediately before medication dose when multiple daily doses are needed. Aboubakr Elnashar
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