Drugs In Pregnancy

• Drug administered to the mother may cross the placenta.

• Numbers of drug prescribed during pregnancy should be restricted to a
  minimum with lowest dose for shortest time.

• The time period between 35-55 days from LMP is most crucial is may
  result in missed abortion or has bad effect on the growing baby.

• USFDA has categorized drugs in categories ABCDX for use in pregnancy.

Maternal drug intake and breast feeding

• Maternal drug intake may have deleterious effect not only on lactation
  but also on the baby through the ingested breast milk
• Any drug ingested by lactating mother may be present in her breast milk
  but the amount – concentration are usually low compared to blood
• Most drugs are compatible with breast feeding . The physician must
  therefore consider the benefit of mother and possible danger the baby may face
  each time drug is prescribed during nursing period.

Maternal medication during pregnancy and fetal hazards

• Maternal foetal drug transfer, prior to implantation , ie during
  embryogenesis drug reach the conceptus through the tubal and uterine section by
  diffusion effect is usually death in case of survival congenital anomaly exist
  during organogenesis.
• During pregnancy mother and baby represent nonsepratable single unit.
• It is important to treat the mother whenever needed while protecting
  the unborn baby to the greatest possible extent.
• During antenatal care what we are give is only nutritional supplements
  and vaccines.
• Women may required treatment for illness during pregnancy for example
  upper respiratory tract infection, urinary tract infection, malaria, epilepsy,
  TB, diabetes, blood pressure , preterm labour pain etc.

DRUGS AND CHEMICAL PROVEN TO BE TERATOGENIC
ALCHOHOL : Foetal alcohol syndrome , during pregnancy alleviate fears
in mild or occasional drinkers who may terminate pregnancy based on unrealistic
perception of risk . Women consuming 2gm/Kg/day during the 1st trimester has 1
to 3 fold high risk for congenital malformation. Alchohol is freely distributed
in the milk. She should not breast feed her baby atleast 2 hour after
consumption of alchohol

NICOTIN: Do not smoke during lactation it can cause infant colic, decresed
milk flow and erlier weaning

STRET DRUGS: It must be avoided such as marijuhana, cocain etc.

Many mothers are required to use drugs during breastfeeding. Almost all
drugs transfer into breast milk and this may carry a risk to a breastfed
infant. Factors such as the dose received via breast milk, and the
pharmacokinetics and effect of the drug in the infant need to be taken into
consideration. Problems should not be overstated however, as many drugs are
considered ‘safe’ during breastfeeding.

Transfer of drugs into breast milk is influenced by protein binding,
lipid solubility and ionisation

Nearly all drugs transfer into breast milk to some extent. Notable
exceptions are heparin and insulin which are too large to cross biological
membranes. The infant almost invariably receives no benefit from this form of
exposure and is considered to be an ‘innocent bystander’. Drug transfer from
maternal plasma to milk is, with rare exceptions, by passive diffusion across
biological membranes. Transfer is greatest in the presence of low maternal
plasma protein binding and high lipid solubility. In addition, milk is slightly
more acidic than plasma (pH of milk is approximately 7.2 and plasma is 7.4)
allowing weakly basic drugs to transfer more readily into breast milk and
become trapped secondary to ionisation. Milk composition varies within and
between feeds and this may also affect transfer of drugs into breast milk. For
example, milk at the end of a feed (hindmilk) contains considerably more fat
than foremilk and may concentrate fat-soluble drugs.

Transfer of drugs into breast milk is most commonly described
quantitatively using the milk to plasma (M/P) concentration ratio. The accuracy
of this value is improved if it is based on the area under the concentration-time
curves (AUC) of the drug in maternal milk and plasma (M/PAUC).

Calculation of infant exposure to drugs can be used to help guide safe
use
The infant’s dose (Dinfant) received via milk can be calculated using
the maternal plasma concentration (Cmaternal), M/PAUC ratio and the volume of
milk ingested by the infant (Vinfant):

Dinfant (mg/kg/day) = Cmaternal (mg/L) x M/PAUC x Vinfant (L/kg/day)
The volume of milk ingested by infants is commonly estimated as
0.15L/kg/day. The infant dose (mg/kg) can then be expressed as a percentage of
the maternal dose (mg/kg). An arbitrary cut-off of 10% has been selected as a
guide to the safe use of drugs during lactation. Drugs such as 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.

As a general rule, maternal use of topical preparations such as creams,
nasal sprays or inhalers would be expected to carry less risk to a breastfed
infant than systemically administered drugs. This is due to lower maternal
concentrations and therefore lower transfer into breast milk. However, the risk
to the infant must be considered in relation to the toxicity of the drug used,
the dosage regimen and the area of application. For example, use of corticosteroids
nasal sprays or inhalers in standard doses would be considered compatible with
breastfeeding.

Other factors to consider in conjunction with the infant’s dose include
the pharmacokinetics of the drug in the infant. Generally, drugs that are
poorly absorbed or have high first-pass metabolism are less likely to be
problematical during breastfeeding. For example, gentamicin is highly
hydrophilic and is very poorly absorbed when administered orally. Should any
gentamicin be ingested via breast milk, it is unlikely to be absorbed.

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CARE & CURE HOSPITAL

(CHANGODAR)

First Floor, 1 - Changodar City Centre, Above Anil Pharmacy,

Changodar, Ta. Sanand, Dist. Ahmedabad.

Call for Appointment: +91 9904453230

Source :  by CARE & CURE HOSPITAL, Changodar, Ahmedabad.

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