Inappropriate ADH secretion

Carbamazepine stimulates antidiuretic hormone activity and has been used for the treatment of neurohypophyseal diabetes insipidus. Carbamazepine induces microsomal enzymes and its metabolism is subject to auto-induction. Frequently occurring adverse effects are sedation, dry mouth, dizziness and gastrointestinal disturbances. Photosensitivity reactions, urticaria and Stevens-Johnson syndrome have been described. The elderly are more prone to mental confusion, cardiac abnormalities and problems due to inappropriate ADH secretion. 

Tetracyclines block ADH in the kidney and especially demeclocycline is used to treat the syndrome of inappropriate ADH secretion. 

Syndrome of inappropriate ADH secretion (SIADH) PO Initially, 900-1200 mg/day in 3-4 divided doses, then decrease dose to 600-900 mg/day in divided doses. 

Adverse effects include local reaction if extravasation occurs, constipation, paralytic ileus, jaw pain, alopecia, bone marrow depression, peripheral neuropathy, inappropriate ADH secretion, shortness of breath and bronchospasm. 

The most important stimulus to the release of ANP from the heart is atrial stretch via mechanosensitive ion channels. ANP release is also increased by volume expansion, changing from the standing to the supine position, and exercise. ANP release can also be increased by sympathetic stimulation via aiA-adrenoceptors, endothelins via the -receptor subtype (see below), glucocorticoids, and vasopressin. Plasma ANP concentration increases in various pathologic states, including heart failure, primary aldosteronism, chronic renal failure, and inappropriate ADH secretion syndrome. 

Stahel RA, Oelz O. Syndrome of inappropriate ADH secretion secondary to vinblastine. Cancer Chemother Pharmacol 1982 8(2) 253-4. 

Diazepam has been reported to cause inappropriate ADH secretion in a neonate (28). 

Vincristine Tissue damage with extravasation Peripheral neuropathy alopecia mild bone marrow depression constipation paralytic ileus jaw pain inappropriate ADH secretion optic atrophy... 

Severe water intoxication caused by inappropriate ADH secretion has been described in an elderly woman taking indometacin (SEDA-17,108). 

Cisplatin-induced nephrotoxicity can be detected by a rise in blood urea or by a fall in creatinine clearance. Tubular dysfunction can cause hyponatremia (72), hypokalemia, hypomagnesemia (173), and hjrpophosphatemia. Inappropriate ADH secretion may be partly responsible for hjrponatremia (191). 

Bone marrow depression alopecia hemorrhagic cystitis sterility (may be temporary) pulmonary infiltrates and fibrosis hyponatremia leukemia bladder cancer inappropriate ADH secretion cardiac toxicity amenorrhea... 

Inappropriate ADH secretion can occur in the presence of water overload and a decline in plasma Na+ concentration and osmolality. Fear, pain, and certain hormone-secreting tumors can cause inappropriate ADH secretion. It leads to hyponatremia and water retention. Morphine and barbiturates increase, and ethanol decreases, secretion of ADH. 

ADH antagonists oppose the actions of ADH and other naturally occurring peptides that act on the same Vj receptor. Such peptides are produced by certain tumors (eg, small cell carcinoma of the lung) and can cause significant water retention and dangerous hyponatremia. This syndrome of inappropriate ADH secretion (SIADH) can be treated with demeclocycline. Lithium also works but has greater toxicity. 

Toxicity Gastrointestinal distress, myelosuppression, and alopecia are expected adverse effects. Hemorrhagic cystitis due to the formation of acrolein may be decreased by vigorous hydration and by use of mercaptoethanesulfonate (mesna). Cyclophosphamide may also cause cardiac dysfunction, pulmonary toxicity, and a syndrome of inappropriate ADH secretion. 

Syndrome of inappropriate ADH secretion (SIADH). In patients with SIADH, ADH is secreted independently of volume or osmolality. Causes include malignancies, pulmonary disease, severe head injury, and some dmgs (see Table 1-26). The serum osmolality is low, but the urine osmolality is inappropriately increased (>300 mOsm/L). The serum blood urea nitrogen (BUN) is usually low (<10 mg/dL). 

---