Pregnancy phenobarbital

The answer is d. (Katzung, pp 411, 1029.) An increased incidence of spina bifida may occur with the use of valproic acid during pregnancy Cardiovascular, orofacial, and digital abnormalities may also occur. The main issue with the use of phenobarbital or primidone (metabolite is phe-nobarbital) for the fetus is neonatal dependence on barbiturates. 

Phenobarbitone is used to treat epilepsy, migraine headache, dental infections, pregnancy vomiting, tetanus, enuresis, chorea, pre and post operative sedation, hypertension, anxiety states, neurosis, and in the treatment of drug and alcohol addiction. This drug is also called phenobarbital. 

Mice treated with phenobarbital (40 mg/kg) on the last 6-7 days before birth showed decreased passive avoidance latencies in the test session at the age of 90 days (ref. 138). Delta-9-THC treatment during pregnancy caused a decreased rate of learning a passive avoidance response on postnatal day 21. However, on day 90 no difference in passive avoidance learning was found (ref. 156). 

Two neonates whose mothers had used phencyclidine during pregnancy had jitteriness, hypertonicity, vomiting, and in one case diarrhea (25). Both had phencyclidine in the urine. Both remained jittery and slightly hypertonic despite treatment with phenobarbital. One was microcephalic. 

Phenobarbital (Luminal) Schedule IV Route Pregnancy Pharmacokinetic Well-... 

Interpretation In normal subjects, serum cortisol concentration is suppressed to 2 pg/dL or less after administration of 1 mg of dexamethasone. Most patients with Cushing s syndrome do not show adequate suppression, and 0800 hours cortisol concentrations are usually >10pg/dL. Serum cortisol >2pg/dL may also be seen in cases of stress, obesity, infection, acute or chronic illness, alcohol abuse, severe depression, oral contraceptive use, pregnancy, estrogen therapy, failure to take the dexamethasone, or treatment with phenytoin or phenobarbital (enhancement of dexamethasone metabolism). 

Partial—simple or complex Valproic acid, phenytoin, carbarn azepine Phenobarbital in pregnancy most newer drugs are also effective... 

Except for the less lipid-soluble aprobarbital and phenobarbital, nearly complete metabolism and/or conjugation of barbiturates in the liver precedes their renal excretion. The metabolic elimination of barbiturates is more rapid in young people than in the elderly and infants, and half-lives are increased during pregnancy partly because of the expanded volume of distribution. Chronic liver disease, especially cirrhosis, often increases the tj of the biotransformable barbiturates. Repeated administration, especially of phenobarbital, shortens the tj of barbiturates that are metabolized as a result of the induction of microsomal enzymes (see above). 

Phenobarbital is considered safest during pregnancy Other anticonvulsant drugs... 

C. Use in pregnancy. FDA category D (possible fetal risk). Phenobarbital readily crosses the placenta, and chronic use may cause hemorrhagic disease of the newborn (owing to vitamin K deficiency) or neonatal dependency and withdrawal syndrome. However, these potential effects do not preclude its acute, short-term use for a seriously symptomatic patient (see p 405). 

Hormonal contraceptives are less reliable during the use of phenytoin and barbiturates such as phenobarbital and primidone. Intermenstrual breakthrough bleeding and spotting can take place, and pregnancies have occurred. Controlled studies have shown that phenytoin and phenobarbital can reduce contraceptive steroid levels. 

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