Pharmacology – Unit 2 – Spring 09

Carla Hilton, MSN, RN, CNE

Lecture 2: Chapters 32, 34 & 37

Learning Outcomes

• Compare and contrast fundamental concepts related to the use of specific central nervous system drugs for sedation and depression with a look at major concepts related to abuse.

• Acquire a working framework for studying drug classifications and nursing implications.

Classification: Antidepressants

Chapter 32

General Points

• Most common psychiatric disorder• Major treatment method - medications

– Five major groups

• Goal? (to make people feel better/functional)• Sxms

– Depressed mood, loss of pleasure / interest in all or nearly all of one’s usual activities

• Under-treated • More prevalent in women• Suicidal thoughts may increase w Rx

Tricyclic Antidepressants (TCAs)

• Prototype: imipramine [Tofranil]• MOA – TE / Use

– Blocks reuptake of the MAO transmitters NE (norepinephrine) and serotonin. Elevates mood, thereby treating depression. (it doesn’t get dissolved as quickly, keep producing it’s effect.)

– Other uses: bipolar disorder, neuropathic pain, insomnia, fibromyalgia, OCD, bladder disorders

– Just b/c they’re taking this, doesn’t mean they are depressed…

• Adverse effects– Orthostatic hypotension, sedation, anticholinergic effects

(neurotransmitter effects), sedation, diaphoresis, cardiotoxicity, seizures, hypomania (they aren’t very interactive with you, “yawngasm”- orgasm that happens when you yawn

– Because it effects neurotransmitters, it has an effect over the entire body

14-2Anticholinergic Effects

• Salivary glands- decreased secretion• Sweat glands- decreased secretion• Bronchial glands- decreased secretion• Heart- Increased rate• Eye- mydriasis, blurred vision• Urinary tract- interference with voiding• Intestine- decreased tone and motility• Lung- dilation of bronchi• High Doses• Stomach- decreased acid secretion

TCAs

• Precautions / Interactions – TCAs w MAOI can lead to severe HTN– Potentiates drugs like NE (norepinephrine)– Potentiate CNS depressants

• Antidote: activated charcoal after gavage (go in and wash out the stomach and wash all the pills out)

• Dosing– Based on clinical response – don’t give more than a week supply

(so they won’t take them all…) – Dose at bedtime once levels achieved – EXCEPT in elderly

(cardiac reasons) (when you’re vertical the fluids in your body they migrate down your body. When you’re laying down the fluids all go back into the system)

SSRI Antidepressants

• Prototype: fluoxetine [Prozac]• MOA / TE / Use

– Selective serotonin re-uptake inhibitor resulting in elevated serotonin levels – elevating mood and relieving depression.

– Helps in bulimia nervosa

• Adverse effects– Impotence, weight gain, Serotonin syndrome (can make you

agitated and angry), withdrawal syndrome, EPS (extraperamital side effects), bruxism (grinding your teeth), bleeding, hyponatremia.

• Interactions: MAOIs, Warfarin (adverse effect of bleeding in SSRI, warfarin thins blood, they bleed lots), & TCAs

MAOI Antidepressants• Prototype: phenelzine [Nardil]• MAO / TE / Use

– Enzyme – deactivates NE, serotonin, dopamine, and tyramine (NE stimulator) from foods

– NOT 1st CHOICE b/c it causes lots of stimulation– Use when all other anti-depression meds don’t work

• Relevant P-kinetics– Tyramine

• Adverse effects: – CNS stimulation – agitation – hypomania – mania – hypotension – HTN

crisis – meperidine (demerol) (hyperpyrexia)

– You have to cut lots of good foods out of your diet, so the pt wouldn’t really want to take this.

Atypical Antidepressants

• Bupropion [Wellbutrin]– Action unclear- often used in smoking cessation– Effect

• Stimulant ergo no wt gain• No sexual dysfunction – may augment

• Adverse effects: – agitation, HA, dry mouth, constipation, wt loss,

insomnia, tachycardia, seizure

• Note: St. John’s Wort Box 32-2

Nursing Implications

ATI p. 203 (220)

Classification:Sedative-Hypnotics

Chapter 34

Overview

• Venacular– Anti-anxiety, anti-anxiolytics, tranquilizers– Hypnotics

• Major Categories – Benzodiazepines, Barbiturates, Barbiturate–Like– Miscellaneous

• Major Effects– CNS depression (the whole head translates down to the whole

body)

• Therapeutic Uses– Relieve anxiety, facilitate sleep, manage muscle spasms,

seizure and panic disorders, augment anesthesia, and manage ETOH withdrawal

Benzodiazepines (CIV)Category D

• Prototype: diazepam [Valium]– Others: clonazepam, lorazepam, clorazepate

• MOA – Depress neuronal function at multiple CNS sites by

potentiating endogenous GABA (gamma-aminobutyric acid) and is limited because GABA is finitesafer

– Cardiac • Very safe PO, effect - heart & blood vessels • IV effect – if given rapidly can cause super BP lowering

– Respiratory• Minimal alone, serious if combo or IV• Incompatible with everything in some forms!

Benzos (cont’d)

• Pharmacokinetics: – Readily absorbed – Differ in respect to time - course of action

• (main indicator for which one chosen for which job)• Adverse effects

– CNS – daytime vs nighttime impacts– Amnesia (usually good b/c they don’t remember the traumatic

procedure)– Paradoxical (it gets the opposite effect you were expecting)– Abuse– Malnutrition (low albumin means higher level of circulating drug),

liver disease and blood levels• DD w other CNS depressants• Dosage: varies by agent

Nursing Implications

• ATI pp. 218

Benzodiazapine-likes

• Prototype: Zolpidem [Ambien] CIV (class 4)• MOA – TE / Use

– Agonists at benzodiazepine receptor site on GABA channel prolonging sleep duration and helps relieve insomnia

– Low potential for tolerance or abuse• Adverse effects

– Similar to benzodiazepines (daytime drowsiness / dizziness)

– Can intensify CNS depressants• Dosage / Administration

– Before bedtime, you want it to kick in by the time you get into bed

– Sleepwalking problems and such

Melatonin Agonist

• Prototype: ramelteon [Rozerem]• MOA / TE / Use

– Activates melatonin receptors and rapidly induces sleep to treat insomnia (melatonin causes sleepiness)

• Adverse effects– Somnolence (you’re kind of apathetic), dizziness, and

fatigue, reduced libido• Precautions…

– ETOH, liver impairment, dangerous activities

Barbiturates

• Prototype: secobarbital [Seconal]• MAO / TE / Use

– Mimics GABA and depresses CNS directly causing relaxation and anxiety reduction. Other uses: seizure management, anesthesia, sleep disorders, mania

• ADME– NO CEILING TO LIMITS OF CNS depression

• Adverse effects:– Resp. depression, hypotension in toxic doses, can readily cause

death• Precautions

– Highly addictive - physical dependence – withdrawal can be severe – Caution in elderly– Caution with other CNS agents– Caution with IM injection

Drug Abuse

Chapter 37

Terms

• Drug abuse

“using a drug in a fashion inconsistent with medical or social norms”• Addiction- you have to have it! You will not eat and steal from your

baby daddy to get your shiz…• Cross-tolerance- if you take a lot of hydrocodone the morphine might

not do you much good. If you’re used to a drug, you might be used to its drug cousin

• Psychological dependence- mentally addicted to chocolate/marijunana• Physical dependence- your body freakin needs it! • Cross-dependence- if you are dependent on a drug, you are very likely

to become addicted to its drug cousin• Withdrawal syndrome

Table 37-1 DSM-IV-TR Diagnostic Criteria for Substance Abuse and Substance Dependence