Drinking water and drug dosage in rat studies

Spontaneously hypertensive rats were treated with verapamil, hydralazine, indapamide or bepridil added to their drinking water. These substances had most different effects on the water consumption of the animals, displaying both positive and negative feed-back mechanisms. Furthermore there were considerable differences in stability of the drugs in solution. It is therefore concluded that continuous control of water intake and analysis of the stability of the drug is essential for the establishment of proper dose-response relationships.