Know this Antidepressant Agents/ Manic Flashcards
Lithium – Adverse Effects
Related to plasma concentration - narrow therapeutic index**
Fine tremor, GI upset, muscle weakness
Decrease in thyroid function (3-30%); possible weight gain
Polyuria, polydipsia (anti-ADH action) (12%)
Moderate toxicity: Confusion, sedation, lethargy, twitching**
Severe toxicity: Seizures, stupor, coma**
Drug Interaction
Diuretics can decrease renal clearance by 25%***
Increase in lithium levels also seen with NSAIDs
Lithium – Pharmacokinetics
Competes with Na+ for reabsorption - Food-Drug Interactions possible
Increase in dietary Na+ –> ↓ Li+ Cp
Na+ restriction –> ↑ Li+ Cp
Lithium – Mechanism of Action
Also interference with Gs and Gi (adenylyl cyclase) can lead to side effects
In thyroid –> anti-TSH –> hypothyroidism
In kidney –> anti-ADH –> polyuria-polydipsia
May affect gene regulation for growth factors and neuronal plasticity
Lithium – Mechanism of Action
Slow onset (10-21 d) – necessary to accumulate Li+ in cell
Effects greatest on cells with highest level of activity (use-dependence)
Enhance 5HT action and/or diminish NE and DA effect – most favored MOA:
Interference with PIP recycling (Gq protein: IP3 and DAG)
Weight Gain
More: TCADs – mirtazapine – paroxetine
Less: fluoxetine – sertraline – venlafaxine
Least: bupropion
Sexual Dysfunction
Less with bupropion and mirtazapine
Anticholinergic side effects
Concern with TCADs (
Arrhythmias
Concern with TCADs (avoid if cardiac disease - ↑ QT)
Orthostatic hypotension
Trazodone - TCADs - MAOIs*
Hypertension
Venlafaxine-Duloxetine
Withdrawal syndrome (flu-like or neurologic symptoms)
Paroxetine and venlafaxine most likely
Fluoxetine least likely
Most agents: ______________-
Additive CNS depressant effects when used with other sedatives
SSRIs + MAOIs –> serotonin syndrome
Hyperthermia, muscle rigidity, myoclonus
Rapid changes in mental status (confusion / agitation) and vital signs (hypertension and tachycardia)
Also SSRIs + opioids: analgesics [meperidine-tramadol] and antitussive [ dextromethorphan]**
SSRI Common Side Effects Acute
Insomnia
Somnolence
Diarrhea
Nausea
SSRI Common Side Effects Delayed onset
Sexual dysfunction
Weight gain
Cognitive blunting
Under-appreciated by physicians, but most concerning to patients
Summary of Pharmacotherapy for Depression
Generic SSRIs are usually first line
Fluoxetine
Summary of Pharmacotherapy for Depression
Equal efficacy
Less weight gain and sexual side effects
Not effective in anxious depression
Bupropion
SNRIs (esp. Venlafaxine)
May be more effective
Side effects > SSRIs
HTN, withdrawal symptoms,
