Some effects of diazepam on the fine structure of human fibroblasts in tissue culture

The effect of exposure to diazepam through the placenta or through the mother's milk. Histological findings in slices of rat brain

Exposure to diazepam during the prenatal or early postnatal developmental period has been reported to result in later behavioural deficits. In the present study morphological changes in the brains of rats that were exposed to diazepam (DZP) prenatally or through the mother's milk postnatally were investigated. The results showed that prolonged prenatal exposure (16 days) to diazepam (10 mg/kg) resulted in characteristic and extensive pathological changes, i.e. gliosis and perivascular cuffing in the brains of the rats. These changes could be observed under the light microscope a long time after exposure to the drug had been terminated. Limiting the prenatal exposure to a single trimester of 7 days reduced somewhat the number of lesions but did not prevent their occurrence. Rats exposed to diazepam postnatally through the mothers' milk showed very few lesions.

Use of benzodiazepines during pregnancy, labour and lactation, with particular reference to pharmacokinetic considerations

Knowledge of the pharmacokinetic properties of the benzodiazepines is playing an increasingly important role in their use during pregnancy, labour and lactation. All of the benzodiazepine derivatives are lipophilic, undissociated agents which readily penetrate membranes. Thus, they exhibit rapid placental transfer with significant fetal uptake of the drug. In the first trimester of pregnancy there is seldom a clear indication for the use of benzodiazepines. In late pregnancy and at parturition there may be more clear indications for their use. During delivery, the lowest effective dose should be used, since after high doses the so-called 'floppy infant syndrome' may occur, and the slow elimination of these agents by the newborn should be considered. Oxazepam, lorazepam, nitrazepam and, especially, flunitrazepam, appear to penetrate the human placenta more slowly than diazepam, but the clinical significance of this phenomenon remains uncertain. All of these derivatives appear in human milk, but only high clinical doses might be expected to exert a possible effect on the nursing newborn.

The possible effect of diazepam on cancer development and growth

Diazepam has the characteristics of a tumour promoter in a number of in vitro systems. The effect is apparent at concentrations of diazepam which are clinically relevant. Diazepam also accelerated tumour growth in two different experimental animal cancers. Tranquillizer use was found to be greater in women with metastatic breast cancer at the time of diagnosis than in those without metastases. Further evaluation of the possible effects of diazepam and related drugs on human and animal cancers is urgently required.

Cardiotoxicity of diazepam in cultured heart cells

The responses of primary cultures of rat myocardial cells to diazepam (Valium) were evaluated. The cells were exposed to 4, 16 or 32 microgram/ml of diazepam for 1, 4 or 24 h. The cultures were evaluated for changes in beating activity and morphology and for cytotoxic effects. After the 1-h treatment exposure, the cultures exhibited tachycardia which was dose-dependent. The longer durations of treatment either produced arrhythmias or caused a loss of beating. Major morphological alterations observed were the formation pseudopodia and increased cytoplasmic granulation. Cytotoxicity was measured quantitatively by leakage of lactic dehydrogenase (LDH) from the cells into the media and by cell viability. Moderate amounts of LDH were leaked from the cells after exposure to diazepam for 4 h. After 24 h of treatment with the higher concentrations of diazepam, cell viability was greatly reduced.