Selective Serotonin Reuptake Inhibitors
Selective Serotonin Reuptake Inhibitors
The SSRIs act as antidepressants by inhibiting CNS neuronal uptake of serotonin with little or no effect on norepinephrine; they are also thought to antagonize muscarinic, histaminergic, and alpha1-adrenergic receptors. The increase in serotonin levels at neuroreceptors is thought to act as a stimulant, counteracting depression and increasing motivation.
Indications
Treatment of depression; most effective in patients with major depressive disorder (SSRIs) Adverse effects
in italics are most common; those in bold are life-threatening. U Do not crush. Treatment of OCD, PTSD, social anxiety, generalized anxiety disorder, panic disorder, PMDD Unlabeled uses: Treatment of bulimia Contraindications and cautions
Contraindicated with hypersensitivity to any SSRI; pregnancy. Use cautiously with impaired hepatic or renal function, diabetes mellitus, lactation. Adverse effects
CNS: Headache, nervousness, insomnia, drowsiness, anxiety, tremor, dizziness, light-headedness, agitation, sedation, abnormal gait, seizures CV: Hot flashes, palpitations Dermatologic: Sweating, rash, pruritus,acne, alopecia, contact dermatitis GI: Nausea, vomiting, diarrhea, dry mouth, anorexia, dyspepsia, constipation, taste changes, flatulence, gastroenteritis, dysphagia, gingivitis GU: Painful menstruation, sexual dysfunction,frequency, cystitis, impotence, urgency, vaginitis Respiratory: URIs, pharyngitis, cough, dyspnea, bronchitis, rhinitis Other: Weight loss, asthenia, fever Interactions
Drug-drug Increased therapeutic and toxic effects of TCAs with SSRIs Decreased therapeutic effects with cyproheptadine Risk for severe to fatal hypertensive crisis with MAOIs; avoid this combination ?Drug-alternative therapy Increased risk of severe reaction with St. John’s Wort Nursing considerations
Assessment
History: Hypersensitivity to any SSRI; impaired hepatic or renal function; diabetes mellitus; lactation; pregnancy Physical: Weight; T; rash, lesions; reflexes, affect; bowel sounds, liver evaluation; P, peripheral perfusion; urinary output; LFTs, renal function tests, CBC Interventions
Arrange for lower dose or less frequent administration in elderly patients and patients with hepatic or renal impairment. Establish suicide precautions for severely depressed patients. Dispense only a small number of capsules at a time to these patients. Black box
warning Monitor children, adolescents, and young adults for suicidal thoughts and behavior, especially when changing dosage. Administer drug in the morning. If dose of more than 20 mg/day is needed, adminis- ter in divided doses. Monitor patient response for up to 4 wk before increasing dose because of lack of therapeutic effect. It frequently takes several weeks to see the desired effect. Provide frequent small meals if GI upset or anorexia occurs. Monitor weight loss; a nutritional consultation may be needed. Provide sugarless candies, frequent mouth care if dry mouth is a problem. Ensure ready access to bathroom facilities if diarrhea occurs. Establish bowel program if constipation is a problem. Establish safety precautions (use side rails, appropriate lighting; accompany patient) if CNS effects occur. Provide appropriate comfort measures if CNS effects, insomnia, rash, sweating occur. Encourage patient to maintain therapy for treatment of underlying cause of depression. Teaching points
It may take up to 4 weeks to get a full antidepressant effect from these drugs. These drugs should be taken in the morning (or in divided doses if necessary). Do not take these drugs during pregnancy. If you think that you are pregnant or you wish to become pregnant, consult your health care provider. You may experience these side effects: Dizziness, drowsiness, nervousness, insomnia (avoid driving or performing hazardous tasks); nausea, vomiting, weight loss (frequent small meals may help; monitor your weight loss—if it becomes marked, consult your health care provider); sexual dysfunction (drug effect); flulike symptoms (if severe, consult your health care provider for appropriate treatment); photosensitivity (avoid exposure to sunlight). Report rash, mania, seizures, severe weight loss. Representative drugs
citalopram desvenlafaxine escitalopram fluoxetine fluvoxamine paroxetine sertraline venlafaxine vilazodone
