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
Examples; phentermine, benzphetamine, diethylproprion, phendiametrazine
and lorcaserin.
Anorexiants are sympathomimetic amines and are thought to exert their
action by stimulation of satiety centers in the hypothalamus and limbic
region. They act through noradrenergic, dopaminergic, or serotonergic
pathways. Lorcaserin promotes satiety by selectively activating 5-
HT2C receptors in the hypothalamus.
Thought to stimulate the release of norepinephrine and/or dopamine from
storage sites in nerve terminals in the lateral hypothalamic feeding center,
thereby producing a decrease in appetite
ADRs- CNS overstimulation, agitation, confusion, insomnia, dizziness,
HTN, headache, palpiatiations, arrhythmias, dry mouth, n/v. Sudden
withdrawal in patients who have a long history of use may cause withdrawal
symptoms. Increases glucose uptake from skeletal muscles and must be used
cautiously in diabetics- altered insulin or oral hypoglycemic dosage
requirements . Carry a high risk of tolerance and dependence. Use with
caution in patients with ahistory of alcohol or drug dependence. Use for a
max period of 6 months.
Lorcaserin is a serotonergic drug and may develop serotonin syndrome if
taken with other serotonergic drugs.
Drug interactions- do not use with SSRIs, careful use with serotonergic
meds due to risk for serotonin syndrome, avoid MAOIs = result in
hypertensive crisis, careful use with adrenergic blockers, insulin
, sulfonylureas, and phenothiazines = lithium toxicity, ovoid orlistat =
decrease levels of levothyroxine and increases warfarin in the body.
Anticonvulsants: Hydantoins, iminostilbenes, succinimides
Mode of Action:
Essentially, anti-seizure drugs act by stimulating an influx of chloride ions;
usually this is associated with the neurotransmitter gamma-aminobutyric
acid delaying an influx of sodium and delaying an influx of calcium.
Hydantoins; phenytoin, ethotoin, fosphenytoin – first line tx for tonic-
clonic and complex seizures and are least sedating drugs for seizure
tx. Hydantoins 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. They also affect the
brainstem's contribution to grand mal seizures and have antiarrhymic
properties.
Metabolism and excretion Metabolism of hydantoins takes
place in the liver; excretion, via the kidneys. Plasma half-lives range from 6
to 24 hours.
Precautions and Contraindications
Hydantoins are contraindicated under conditions of hypersensitivity.
Phenytoin-induced hepatitis is a common hypersensitivity reaction.
Other hypersensitivity reactions include fever, rash, arthralgias, and
lymphadenopathy. Phenytoin may cause severe cardiovascular events
and death has resulted from too-rapid IV administration. 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. Phenytoin is contraindicated in sinus
bradycardia, sinoatrial block, second- and third-degree atrioventricular
block, and Stokes–Adams syndrome. It should be used cautiously in
patients with hepatic or renal disease. Ethotoin is contraindicated in
the presence of hepatic or hematological disorders.
Black box warning for IV administrations – do not give too fast or can