Drugs in pregnancy and lactation By Mariam Talal Yusor Jaffar Sherin Raad
Pharmacokinetics in pregnancy• Absorption• Albumin and albumin binding capacity• Metabolism • Excretion• Most drugs are expected to have shorter
half life during late pregnancy• During labor, the drug concentration may
increase rather than decrease
• Drug transfer is greater during late gestation because
• Pathological processes can affect uteroplacental blood flow
• Certain drugs can also induce or inhibit placental enzymes
Drug effects on the fetus• Chronic drug exposure rather than single-
dose therapy may influence fetal cell growth
• Drug may act as teratogenic agent in many ways
• Cardiac output is greater in fetus than adult
• Blood-brain permeability is greater in the fetus
• Mitochondrial number increase in in the fetal brain and heart
• Total body water and plasma protein• Autonomic receptors• Human fetal liver microsomes• Excretion of most drug is slower in fetus
Fetal drug therapy
• Specific fetal tissues may be more selective in drug uptake
• Drug administration can occur by:
I. Passive transplacental route
II. Direct intra-amniotic intramuscular injection
Drug effects on the fetusThe effect of a teratogen is depend on:
I. The dose reaching the developing embryo or fetus
II. Gestational age
III. Duration of exposure
IV. The genotype of the mother and the fetus
V. Effect of other agents
VI. Difficulty to prove a drug effect