NR 565 / NR565 Week 4 Study Guide

NR 565 / NR565 Week 4 Study Guide. Week 4 is the midterm (no quiz) and includes all material from Weeks 1-4; Be sure to also review the Weeks 1, 2 & 3 study guides to prepare for the exam Many questions will are written to assess your clinical application of the material from the textbook, in real-world scenarios Chapter 15: Drugs Affecting the Central Nervous System Anorexiants: Precautions and contraindications  Tolerance/Dependence (physical & psychological) o Use cautiously in pts w/ history of drug/alcohol abuse (cross tolerance)  Actively drinking taking anorexiants may have depression, paranoia, psychosis  Contraindicated in pts who abuse cocaine, meth (Adrenergic stimulation)  Use maximum of 6 months  Diabetics may experience altered insulin/ hypoglycemic oral concentrations  Lorcaserin (serotonergic anorexiant drug)- may experience serotonin syndrome or neuroleptic malignant syndrome o Category X pregnancy drug Anticonvulsants: Hydantoins  Metabolism and excretion Hydantoins Metabolized by liver, excreted by kidneys  MOAs, indications Hydantoins (Phenytoin) MOA- inhibit and stabilize electrical discharges in the motor cortex of the brain by affecting the influx of sodium ions into the neuron during depolarization and repolarization, slowing the propagation and spread of abnormal discharges. Indications- First line treatment of choice for tonic-clonic and partial complex seizures— least sedating drugs to treat seizure disorders  Absolute contraindications Sinus bradycardia, SA Block, 2ond/3rd degree AV block, Stokes-Adams syndromes Ethotoin- Hepatic/hematological disorders  Precautions Pregnancy category D Newborns exposed to phenytoin – mom gets Vit K and baby at birth Liver/Kidney disease (Careful) Rebound status epilepticus if d/c’d abruptly  Monitoring Patients should be assessed for phenytoin hypersensitivity syndrome (fever, skin rash, lymphadenopathy), which usually occurs at 3 to 8 weeks. Baseline complete blood count, urinalysis, and liver function tests should be assessed prior to onset of treatment, with frequent reassessment during the first few months of treatment. Plasma levels should be monitored, especially when drugs that increase plasma hydantoin, such as ibuprofen, are used. Suicide Risk Assessment  Adverse drug reactions e CNS effects such as agitation, ataxia, confusion, dizziness, drowsiness, headache, and nystagmus; cardiovascular effects such as hypotension, tachycardia, atrial and ventricular conduction depression, and ventricular fibrillation; gastrointestinal (GI) effects such as nausea, vomiting, anorexia, altered taste, constipation, dry mouth, and gingival hyperplasia; and genitourinary effects such as urinary retention and reddish-brown discoloration of the urine. Serious dermatologic reactions, including Stevens–Johnson syndrome and toxic epidermal necrolysis may occur. Other possible adverse effects include skin rashes (scarlatiniform or morbilliform), hyperglycemia, tinnitus, gynecomastia, coarsening of facial features and enlargement of the lips, hematopoietic changes, photophobia, and polyarthropathy.  Drug interactions (including oral contraceptives) Concurrent administration causes the decreased effect of carbamazepine, estrogens, corticosteroids, haloperidol, methadone, levodopa, sulfonylureas, oral contraceptives, and cardiac glycosides Will make oral contraceptives less effective  Black box warnings Phenytoin has a Black-Box Warning that IV administration should not exceed 50 mg/minute in adults and 1 to 3 mg/kg/minute in pediatric patients owing to risk of cardiovascular reactions associated with a too rapid rate of administration. Iminostilbenes  Metabolism and excretion Iminostilbenes Carbamazepine – metabolized by liver- induces its own metabolism (autoinduction)---Excreted via urine/feces Initial concentrations may fall later Induces metabolism of many CYP450 Enzymes and other substrates  MOAs, indications treat epilepsy, bipolar affective disorder, aggressive and assaultive behavior, and some neuralgias. thought to affect the sodium channels, slowing influx of sodium in the cortical neurons and slowing the spread of abnormal activity. Carbamazepine exerts its effect by depressing transmission in the nucleus ventralis anterior of the thalamus. This area is associated with the spread of seizure discharge. Other actions not explained by effects on sodium channels include anticholinergic, antidiuretic, antidysrhythmic, and antidepressant activity.  Absolute contraindications  Precautions Carbamazepine is Pregnancy Category D; teratogenic defects have occurred, including spina bifida. It is excreted in human milk but is not contraindicated during lactation. Oxcarbazepine is Pregnancy Category C; it crosses the placenta and adverse effects have been noted in animal studies, but no well-designed human studies have been done. It is recommended that pregnant patients taking oxcarbazepine (Trileptal) be enrolled in the NAAED Pregnancy Registry (1-888- 233-2334 or ).  Monitoring Patients taking carbamazepine and oxcarbazepine should be monitored for seizure activity, severity, and duration. Adverse effects should be monitored, including CNS depression and suicidality or behavioral changes. Plasma carbamazepine levels should be monitored on a regular basis. Oxcarbazepine does not require serum level monitoring. Serum sodium levels should be monitored for the first 3 months of therapy, especially if the patient is taking other drugs that may cause hyponatremia.  Adverse drug reactions  Drug interactions (including oral contraceptives) Oxcarbazeine may decrease the effectiveness of hormonal contraceptives containing ethinylestradiol and levonorgestrel.  Black box warnings lack-Box Warning regarding serious dermatological reactions, particularly among patients of Asian ethnicity. (Stevens–Johnson syndrome and toxic epidermal necrolysis) and the risk of developing aplastic anemia and agranulocytosis. Patients of Asian ethnicity should be screened for the presence of the HLA-B*1502 genetic variant prior to starting carbamazepine. Carbamazepine has a Black-Box Warning due to its potential to cause blood dyscrasias, some potentially lethal. Although a transient decrease of the white blood cell count can occur and is manageable, carbamazepine can depress the bone marrow and lead to leukopenia, thrombocytopenia, agranulocytosis, and aplastic anemia. Succinimides The succinimides exert their anticonvulsant effects by decreasing nerve impulses and transmission in the motor cortex. This produces a variety of effects, including an increase in the seizure threshold and reducing the electroencephalogram (EEG) spike-and-wave pattern of absence seizures.  Metabolism and excretion Succinimides- metabolized through liver and excreted in urine  MOAs, indications...............................................................................