Drug-induced endocrine disorders

Plasma prolactin response to gonadotropin-releasing hormone during benzodiazepine treatment

Previously we observed that prolactin (PRL) is secreted in response to gonadotropin-releasing hormone (GnRH) in normal women during the periovulatory phase of the menstrual cycle. Because sedative drugs affect the neurotransmitters involved in the regulation of PRL secretion, we investigated PRL responsiveness to GnRH in pre- and postmenopausal female subjects during prolonged treatment with benzodiazepines (six-60 months). In both pre-and postmenopausal patients who were not on benzodiazepine treatment, GnRH infusion (0.2 micrograms/min for 3 hr) was ineffective in eliciting a PRL response. In six premenopausal women treated with benzodiazepines, basal PRL concentrations were not influenced by the drug in four subjects (range 4.0-15.7 ng/ml) and were slightly elevated in two subjects (23 and 30 ng/ml). In six treated postmenopausal women, basal PRL concentrations were in the normal range (7.5-11.0 ng/ml). GnRH infusion induced a progressive increase in PRL concentrations which reached a peak at 120 min in the premenopausal subjects (mean % SEM increase: 64 +/- 30.5%) and at 60-90 min in the postmenopausal subjects (mean % increase: 110.6 +/- 34.7%). A saline infusion, performed on a separate day during benzodiazepine treatment as a control, did not influence PRL.

Effect of ten new beta-lactam antibiotics on urine glucose test methods

The effect of ten new beta-lactam antibiotics (cefoperazone, cefotaxime and its metabolite desacetylcefotaxime, ceftazidime, ceftizoxime, ceftriaxone, aztreonam, azlocillin, mezlocillin, piperacillin, and ticarcillin) on the accuracy of Clinitest, Diastix, and Tes Tape determinations of glycosuria was investigated. Solutions of each of the antibiotics were prepared in urine over a range of clinically obtainable drug concentrations. Urine samples from a healthy subject were used to prepare simulated diabetic urine by adding dextrose to achieve concentrations of 0.5%, 1%, and 2%. With penicillin derivatives, falsely elevated Clinitest readings generally were observed at lower glucose concentrations. When no glucose was present, cephalosporins and the monobactam, aztreonam, gave a dark green-black color that could only be interpreted as 0% on the Clinitest color chart. At higher urine glucose concentrations (1% and 2%), no interaction with Clinitest could be demonstrated, with the exception of a few falsely reduced readings. All urine solutions containing beta-lactam antibiotics were estimated accurately by both Diastix and Tes Tape. The unpredictability of the Clinitest-beta-lactam antibiotics interaction should discourage the use of this urine glucose test in patients who receive these drugs. The glucose-oxidase tests, Diastix and Tes Tape, may be used as qualitative tests for glycosuria in patients treated with beta-lactam antibiotics.

The benzodiazepine agonist diazepam inhibits basal and secretagogue-stimulated prolactin release in vitro

Benzodiazepines reduce basal and stimulated rat prolactin (PRL) serum levels in vivo. We investigated whether the inhibition of PRL secretion by the benzodiazepine receptor agonist, diazepam, occurs directly at the pituitary. At nanomolar concentrations diazepam did not affect PRL secretion, whereas at micromolar concentrations, diazepam dose-dependently inhibited basal and secretagogue-stimulated PRL release from hemipituitary glands and from primary cultures of rat anterior pituitary cells. The inhibitory effect of the highest concentration of diazepam (100 microM) was abolished when the pituitary tissue was incubated with the benzodiazepine receptor antagonist Ro 15-1788. Although nanomolar concentrations of diazepam alone did not affect PRL release, they did enhance the PRL inhibitory effect of muscimol, a gamma-amino butyric acid (GABA) receptor agonist. Neither diazepam nor muscimol affected cellular adenosine 3',5'-monophosphate (cAMP) content. Since these effects do not appear to occur through an inhibition of the cAMP generating system, diazepam may inhibit PRL release via a cAMP-independent pathway. We suggest that diazepam inhibits PRL secretion either by enhancing the GABAergic inhibition of PRL release, or by inhibiting, at micromolar concentrations, a benzodiazepine-sensitive Ca2+-calmodulin dependent protein kinase.

Adverse effects of antianxiety drugs

Antianxiety drugs, like other drugs used in psychiatry, can cause a wide range of adverse effects. Many physiological systems may be affected, but, as the main action of antianxiety drugs is on the central nervous system, this system is particularly vulnerable. All antianxiety drugs have the potential to produce untoward effects on higher cerebral functions, although the effect seen is also influenced by psychological and social factors. The most common effects is oversedation, which is a particular problem for the very young and the very old. It is also a serious problem for those who drive motor vehicles and may be a hazard when working in dangerous situations. Subjects are especially vulnerable when (a) antianxiety drugs are first introduced; (b) the dose is increased; and (c) these agents are taken in combination with alcohol and other drugs. Dependence on antianxiety drugs is well known, but only recently has it been recognised that dependence on benzodiazepines is a larger problem than previously realised. Other adverse effects are reviewed and summarised according to the system they predominantly affect. A review of this kind can easily give a biased impression of the dangers of antianxiety drugs; it should be made clear at the outset that many effects are rare, and in some instances a causal connection with the drug has not been established with certainty. Overall, benzodiazepines are the most widely used of all drugs and are remarkably safe-even when taken in massive overdoses. Some unwanted effects are readily preventable if antianxiety drugs are used with caution or avoided altogether in conditions where pathological disturbances of tissue sensitivity or drug disposition lead to exaggerated reactions. Particular care should be taken when prescribing these drugs for children and the elderly, and drugs that are not clearly essential for the well-being of the mother should be avoided during pregnancy and breast feeding. Antianxiety agents are grossly overprescribed. The frequency of occurrence of some adverse effects is therefore not so much a manifestation of the intrinsic toxicity of antianxiety drugs, but a reflection of their widespread use. Overprescribing and irrational prescribing also contribute to self-poisoning with these and other agents and to the cost of health services. The reasons for overprescribing are complex, but one contributing factor is the ready availability of effective antianxiety drugs.