sucralfate , Cholestyramine , colestipol , Kayexalate . Other substances cause other adverse effects that may be severe. Ketamine may cause hypertension and tachycardia and Tricyclic and tetracyclic antidepressants increase its toxicity.On the other hand Lithium causes hyperthyroidism by affecting iodine metabolism of the thyroid itself and thus inhibits Synthetic levothyroxine