Treatment of hypothyroidism in dogs.
Contra-indications, warnings, etc
Do not use in dogs with hyperthyroidism or uncorrected adrenal insufficiency (hypoadrenocorticism).
Do not use in case of hypersensitivity to levothyroxine sodium or to any of the excipients.
The product should be used with caution in dogs with cardiac disease, diabetes mellitus or treated adrenal insufficiency (hypoadrenocorticism). Levothyroxine therapy should be gradually introduced for these dogs. Start with 25% of the normal dose (5μg/kg once daily) and increase by 25% increments every two weeks until stabilised.
Adverse reactions associated with L-thyroxine sodium treatment are primarily those of hyperthyroidism, due to therapeutic overdose.
They include weight loss, hyperactivity, tachycardia, polydipsia, polyuria, polyphagia, vomiting and diarrhoea. Transient, self-resolving skin reactions such as mild to moderate scale formation may occur.
Use in pregnancy
The safety of use in pregnant bitches, lactating bitches or animals intended for future breeding has not been evaluated. However, thyroxine is essential for normal foetal development. Hypothyroidism during pregnancy may be associated with impaired cognitive development and increased foetal mortality. During pregnancy, maternal thyroid hormone requirements may increase. Pregnant and lactating bitches receiving treatment should be monitored on a regular basis as dose requirements may change during pregnancy and lactation.
Use in lactating bitches or animals intended for future breeding has not been evaluated.
L-thyroxine absorption may be impaired by the concurrent administration of antacids, e.g. aluminium or magnesium salts or calcium carbonate, or ferrous sulphate and sucralfate. Therefore, Leventa should not be administered within 2 hours of such products.
The therapeutic response to Leventa may be altered by compounds which influence thyroid hormone metabolism and disposition (e.g. drugs displacing protein-binding site, modifying serum thyroxine-binding globulin concentration, or altering hepatic degradation of thyroxine or peripheral conversion of thyroxine to tri-odothyronine). Thus, if Leventa is administered concurrently with a compound exhibiting such properties, thyroid hormone concentrations should be monitored and the dose of Leventa adjusted if needed. Conversely, L-thyroxine supplementation may affect the pharmacokinetics and activity of concurrent therapies. In diabetic dogs treated with insulin, L-thyroxine supplementation may alter insulin requirements. In dogs with cardiac insufficiency, therapeutic response to cardiac glycosides may be decreased by L-thyroxine supplementation. Therefore, dogs receiving such products should be monitored carefully during initial treatment with Leventa.
Clinical signs of overdose with L-thyroxine are identical to those of hyperthyroidism and include body weight loss, hyperactivity, tachycardia, polydipsia, polyuria, polyphagia and diarrhoea. These signs are generally mild and fully reversible. Overdose may be accompanied by reversible changes in blood biochemistry, e.g. elevated glucose, inorganic phosphorus and albumin:globulin ratio, and reduced total protein and cholesterol.
In the case of accidental ingestion, seek medical advice immediately and show the package leaflet or the label to the physician. Note: this product contains a high concentration of L-thyroxine sodium and may present a risk to humans if ingested.
Wash hands after use.
In case of eye contact, flush immediately with water.
For animal treatment only. Keep out of the reach and sight of children.
Store in a refrigerator (+2°C to +8°C). Store in the original container. Once opened use the product within 6 months.
30 ml amber glass bottle with a transparent LDPE insert and with a white HDPE child-resistant cap with tamper-proof closure in a printed carton.
A 1 ml oral syringe graduated in 0.05 ml increments is supplied with the product.
Pack sizes: 1 x 30 ml, 6 x 30 ml and 12 x 30 ml. Not all pack sizes may be marketed.
In a tolerance study, healthy dogs treated with Leventa at 40 μg/kg body weight once daily for 91 consecutive days did not present any adverse clinical signs. At dose rates of 120 and 200 μg/kg body weight, dogs did not exhibit signs other than those of hyperthyroidism, mainly weight loss. These signs were mild and reversible, with recovery occurring within 5 weeks after cessation of treatment. In the event of an overdose standard measures should be taken to remove non-absorbed drug from the gastro-intestinal tract.
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