Thyroxyl Tablets Contra-indications, warnings, etc Do not use in dogs with thyrotoxicosis or uncorrected adrenal insufficiency. The effects of Thyroxine therapy are slow in being manifested. Administer with caution to animals with clinically significant heart disease, hypertension or other complications for which a sharply increased metabolic rate might prove hazardous. Chronic overdosage will eventually lead to thyrotoxicosis, manifested by: panting, nervousness, tachycardia, aggressive behaviour, polyuria, polydipsia, polyphagia and weight loss. If you notice any serious effects or other effects not mentioned in the leaflet, please inform your veterinary surgeon. Operator warnings: Wash hands after use. In case of accidental ingestion, seek medical advice immediately and show the doctor the leaflet. General precautions: For animal treatment only.