Emergency treatment with calcitonin of hypercalcaemia associated with multiple myeloma.

carbamazepine are very similar to the clinical features of water intoxication. Dizziness, headaches, nausea, and mental confusion may occur with both, although it is not known what proportion of patients who develop these side effects on carbamazepine do so because of a fall in the plasma osmolality. When untoward symptoms develop during treatment and subside after the dose is reduced the mechanism of production of the side effect is usually not investigated. Water retention may itself have an adverse effect on epilepsy,6 and, as a result of our experience, we wonder whether this may account for the apparent failure of carbamazepine to improve the control of epilepsy in some patients. Measurement of serum drug levels now has a recognised place in the management of epilepsy, and if the serum carbamazepine level is high, as in our second case, the plasma sodium should be measured. If the sodium concentration is low the dose of carbamazepine should be reduced or stopped. Special care should be exercised when carbamazepine is given to elderly patients and those with cardiovascular disease. If symptoms consistent with water intoxication occur the plasma sodium and osmolality should be checked. Hyponatraemia is, then, another indication to reduce or stop carbamazepine.