Exam 2- Week 4 (CNS)

Question 1

Carbamazepine (Tegratol)

Answer 1

Anticonvulsant. Also for nerve pain.
thought to affect the sodium channels, slowing influx of sodium.

It is absorbed through the stomach. highly lipohilic, It is metabalized in the liver and has the unique ability to induce its own metabolism (autoinduction). Peak blood levels occur 6 hours after administration. Half-life is 12-17 hours but can be up to 65. Steady state is obtained in 2-4 days. Renally excreted.

Warnings: SJS, anemia or agranulocytosis. Bone marrow suppression. Severe derm reactions (SJS and TEN) for patients with HLA-B*1502 allele.

Monitoring: baseline and periodic CBC with platelet count d/t risk of anemia and agranulocytosis, retic, iron, LFTs, etc. test for HLA-B*1502 allele in Asian decent to prevent severe dermatological reaction.

Question 2

Topiramate

Answer 2

Anticonvulsant
Pregnancy cat D
Patients may have decreased concentrations of serum bicarbonate leading to hyperchloremic metabolic acidosis.

Question 3

Valproate

Answer 3

Anticonvulsant. Works on GABA receptors.

Alert: hepatotoxicity resulting in fatalities, especially in patients <2yo; high fetal risk; life-threatening pancreatitis

Therapeutic range for epilepsy: 50-100

Pregnancy category D.
Find another way to control seizures in pregnant pts

Question 4

Tricyclic antidepressants

Answer 4

Block reuptake of serotonin and norepinephrine at the presynaptic neuron. Also act on histamine and acetylcholine.

Well absorbed orally, widely distributed. Undergo first-pass metabolism and enterohepatic recirculation.

Side effects: anticholinergic adverse efects such as dry mouth, constipation, urinary hesitancy or retention, blurred vision, sedation,

contraindicated in cardiovascular disorders. Use with caution in patients with glaucoma, prostatic hypertrophy, or urinary incontinence. They should not be prescribed in combination with MAOIs.

Question 5

Phenelzine (Nardil)

Answer 5

MAOI

Alert: increased suicidality in children, adolescent, and young adults.

Irreversibly inactivate the enzymes that metabolize norepinephrine, serotonin, and dopamine. also prevent the breakdown of tyramine, found in many food that are aged or fermended. Tyramine is toxic to humans, contributing to rapid extreme hypertension. Do not give concurrently with other drugs or foods that raise blood pressure, including anticholinergics, sympathomimetics, stimulants, and foods containing tyramine.

Question 6

Hypertensive crisis

Answer 6

Symptoms: Headache, heart palpitations, stiff or sore neck, chest tightness, tachycardia, sweating, and dilated pupils.

Result of MAOI mixed with foods containing tyramine or drugs that elevate BP.

Question 7

SSRIs

Answer 7

Antidepressant

Affect serotonin by blocking the serotonin transporter from returning the remaining serotonin to the presynaptic cell.

May not see effects on depression for 3-4 weeks.

Well-absorbed orally, significant first-pass effect, metabolized by CYP450 system, majority eliminated in urine

Side effects: nausea, dry mouth, dizziness, headache, insomnia, restlessness, and hypotension.

Meds: Prozac, citalopram, seetraline, escitalproam

Question 8

Lithium

Answer 8

Low-salt diet

Question 9

MAOIs

Answer 9

Irreversibly inactivate the enzymes that metabolize norepinephrine, serotonin, and dopamine. Prevent breakdown of tyramine (toxic to humans), contributing to rapid extreme hypertension.

Precautions: Do not give concurrently with other drugs or foods that raise blood pressure, including anticholinergics, sympathomimetics, stimulants, and foods containing tyramine.

Rapidly absorbed orally with extensive 1st pass metabolism. Excreted by kidneys. Pts begin to experience therapeutic effects immediately

Side effects: dizziness, headache, insomnia, restlessness anticholinergic effects .

Ex: nardil, Emsam

Question 10

SNRIs

Answer 10

Block serotonin and norepinephrine transporters, inhibiting reuptake.

Rapidly absorbed orally and extensively metabolized in the liver

Side effects: nausea (common), high BP, headache, somnolence, dizziness, insomnia, nervousness, nausea, dry mouth, constipation, and abnormal ejaculations.

Ex: venlafaxine, desvenlafaxine, duloxetine

Question 11

Benzodiazepines

Answer 11

Increase the action of GABA receptors, decreasing effect of neuronal activity. Decrease anxiety, relax muscles, ataxia, anticonvulsant activity

Rapidly and widely distributed following oral admin. Short and long acting. Metabolized in liver.

Question 12

CNS transmitters

Answer 12

GABA
Acetylcholine 
Serotonin 
Dopamine 
Norepinephrine

Question 13

Buspirone (Buspar)

Answer 13

Atypical antidepressant. Norepinephrine-Dopamine reuptake inhibitor.

Approved for tx of GAD. full antagonist at the pre-synaptic serotonin-1A receptor. Also has action at dopamine receptors.

Absorbed well orally. Should be taken with food to decrease 1st-pass effect.

Short half-life, but slow onset of action. Excreted in urine.

Question 14

Barbiturates

Answer 14

Used commonly for anxiety, insomnia prior to BZDs. Bind to GABA receptors (at a different site) and cause prolonged opening of he Cl channel.

Pregnancy cat D

Precautions: severe CNS depression, esp when combined with ETOH. significant abuse potential.

Question 15

Serotonin

Answer 15

Neurotransmitter involved in depression
Influences anxiety, sexual behavior, appetite, aggression, pain, obsessions, emesis, learning, psychosis, migraine, sleep, suicidal ideation.

Question 16

Norepinephrine

Answer 16

Neurotransmitter involved in depression

Influences level of activity, alertness, appetite, sleep patterns

Question 17

Dopamine

Answer 17

Neurotransmitter involved in depression

Influences sleep, sexual behavior, level of anxiety and agitation, feelings of euphoria, addictions

Question 18

Atypical antipsychotics

Answer 18

Generally have less dopamine blocking than other antipsychotics, resulting in fewer EPS sx’s

Side effects: sedation, weight gain, hyperglycemia, high cholesterol

Question 19

Psychomotor stimulants

Answer 19

Sympathomimetic amines that act as dopamine agonists.

Rapidly absorbed orally with quick onset of action. Biotransformed in liver and excreted in urine.

Question 20

Anorexiants

Answer 20

Stimulate satiety center in hypothalamus. Used for short-term management of obesity.

Ex: phentermine, meridia

Question 21

Serotonin agonists

Answer 21

Triptans

Block serotonin receptors, preventing release of vasoactive peptides.

Adverse effects: dizziness, tingling sensation in chest and throat.

Avoid in CV dz. multiple drug interactions.

Question 22

Linezolid

Answer 22

Reversible, nonselective MAOI

Drug interactions: Indirect-acting sympathomimetics, vasopressors, or dopaminergic drugs may have increased effects when given concurrently, requiring decreased doses of these drugs. Because linezolid is a reversible, nonselective inhibitor of monoamine oxidase, it also has potential interactions with serotonergics such as SSRIs, tricyclic antidepressants, ondansetron, meperidine, buspirone, methadone, and tramadol. Signs and symptoms of serotonin syndrome (e.g., hyperpyrexia and cognitive dysfunction) should be watched for if concomitant therapy is required. There is also potential interaction with tyramine-rich foods and beverages. They do not need to be eliminated entirely but should not be eaten in large quantities