Benzodiazepines (BZDP) potentiate the activity of GABA, a major inhibitory neurtransmitter in the CNS. The drugs cause sedative-hyponotic, muscle relaxant, anxiolytic and anticonvulsant effects. Clinically one may see sedation, impaired psychomotor skills, cognitive dysfunction, and short-term memory impairment. Rarely, BZDP may cause paradoxical effects. Tolerance to the sedative effects occurs over days, possibly over periods as short as hours.
The discovery of specific BZDP receptors in the CNS lead to the search for endogenous BZDP-like substances. Endozepines have been purified from animals and a similar substance has been quantified from human breast milk (in women not taking exogenous BZDP). The source of these substances is controversial (food, bacterial modification of precursors in the GI tract or endogenous formation)
BZDP cross the placenta and accumulate in the fetus in concentrations that are greater than maternal concentrations. Animal studies suggest that congenital malformations and fetal loss occur when BZDP are used during pregnancy. BZDP taken before or during labor can cause the floppy baby syndrome. BZDP and their metabolites are excreted in breast milk in clinically significant amounts. Nursing infants can become lethargic and hypotonic when mothers are taking these drugs.
Next week: BZDP OD and Flumazenil
As always, if there are any questions, call the MTPC.
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