Title 12. TDM OF DRUGS USED IN PSYCHIATRIC CONDITIONS.pdf ✅

PHARMD GURU Page 1 THERAPEUTIC DRUG MONITORING OF LITHIUM: GENERAL INTRODUCTION: Lithium has been used to treat manic episodes since the 19th century. Though it is widely used, its mechanism of action is still unknown. Lithium carbonate has a narrow therapeutic range and so careful monitoring is required to avoid adverse effects. USES:  Lithium is used as a mood stabilizer, and is indicated for the treatment of manic episodes and maintenance of bipolar disorder.  Lithium is a mood-stabilizing agent indicated as mono-therapy for the treatment of manic and mixed episodes in patients with bipolar disorder. It is also used as maintenance therapy in patients with bipolar disorder. MECHANISM OF ACTION: The exact mode of action of Lithium is unknown. Some proposed modes of action are alteration of intra neuronal metabolism of catecholamines and alteration of sodium transport in nerve and muscle cells. PHARMACOKINETIC PROFILE: a) ABSORPTION:  Lithium absorption is rapid and oral bioavailability is close to 100%. b) DISTRIBUTION:  Apparent volume of distribution is 0.7 to 1.0L/kg.  Protein binding: Lithium carbonate is not significantly protein bound. c) METABOLISM:  Lithium carbonate is not metabolized before excretion. d) EXCRETION:  Lithium is primarily eliminated through the kidneys and elimination in the feces is insignificant. TDM OF DRUGS USED IN PSYCHIATRIC CONDITIONS