Psychology
Lithium
Lithium is a common ‘mood stabilizer’ used to treat the manic episodes of bipolar disorder, a mood disorder that is characterized by episodes of mania, hypomania, and depression. ⠀
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The exact cause of bipolar disorder is unknown but is highly linked to family history, genetics, and abnormalities in neurotransmitters. This makes it tricky to pinpoint exactly how lithium works to treat bipolar but there are many proposed mechanisms of action. ⠀
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Whenever you see the medication lithium, always think SALT as lithium (Li+) is located close to sodium (Na+) on the periodic table and they share similar structures. Because of this, lithium levels are often affected by salt and water balance as well as renal function (excreted mainly through kidneys). ⠀
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Dehydration can cause lithium levels to increase while increasing sodium intake can cause lithium levels to decrease. Medications that affect water and salt balance (ex: diuretics, NSAIDs, ACEI) can also alter lithium concentrations. ⠀
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The starting dose of lithium is 300 mg two or three times a day (The brand name is Lithobid to help you remember that it can be given BID or twice daily)⠀
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Lithium is considered teratogenic due to the potential for fetal cardiac defects. The risks and benefits should be discussed with a healthcare provider before starting it in women of childbearing age.⠀
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Lithium is a popular drug that often shows up on tests due to its narrow therapeutic index and many side effects. ⠀
Antidepressants
Major depressive disorder (MDD) is a mood disorder characterized by persistent feelings of sadness and loss of interest that interferes with normal daily functioning.
The exact chemical basis for depression is poorly understood but is thought to be linked to decreased levels of the neurotransmitters, serotonin, dopamine, and norepinephrine. This cause is also known as the monoamine hypothesis.
Because of this, the drugs developed to treat MDD selectively target the reuptake of serotonin and norepinephrine, increasing levels of these neurotransmitters in the synapse and enhancing NT signaling.
SSRIs are generally first-line due to their improved tolerability compared to the others (TCAs and MOAIs) and relative safety in cases of overdose.
Studies have shown equivalent efficacy among antidepressants, therefore the initial choice is made empirically based on patient factors and the nuances of each drug.
Antipsychotics
SSRIs Side Effects
SSRIs Side Effects Read More »