Pharm Part2: Chapter 12

Muscle Relaxants

-Act to relieve pain associated with skeletal muscle spasms -Majority are centrally acting. *CNS is the site of action. *Similar in structure and action to other CNS depressants -Direct acting *Act directly on skeletal muscle *Closely resemble GABA

Barbiturates: Drug Interactions

-Additive effects *Alcohol, antihistamines, benzodiazepines, opioids, tranquilizers -Inhibited metabolism *MAOIs prolong the effects of barbiturates. -Increased metabolism *Reduces anticoagulant response, leading to possible clot formation

Common Muscle Relaxants

-Baclofen (Lioresal) -Cyclobenzaprine (Flexeril) -Dantrolene (Dantrium) -Metaxalone (Skelaxin) -Tizanidine (Zanaflex) -Carisoprodol (Soma) -Chlorzoxazone (Paraflex) -Methocarbamol (Robaxin)

Nursing Implications

-Before beginning therapy, obtain a thorough history regarding allergies, use of other medications, health history, and medical history. -Obtain baseline vital signs and I&O, including supine and erect blood pressure. -Assess for potential disorders and conditions that may be contraindications and for potential drug interactions -Give hypnotics 30 to 60 minutes before bedtime for maximum effectiveness in inducing sleep (depends on drug's onset). -Most benzodiazepines cause REM rebound and a tired feeling the next day; use with caution in older adults. -Instruct patients to avoid alcohol and other CNS depressants.

Benzodiazepines: Drug Effects

-Calming effect on the CNS -Useful in controlling agitation and anxiety -Reduce excessive sensory stimulation, inducing sleep -Induce skeletal muscle relaxation

Hypnotics

-Cause sleep -Much more potent effect on CNS than sedatives -A sedative can become a hypnotic if it is given in large enough doses.

Interactions

-Caution with other CNS depressants *Benzodiazepines *Alcohol

Nursing Implications (Cont.)

-Check with the prescriber before taking any other medications, including over-the-counter medications. -Rebound insomnia may occur for a few nights after a 3- to 4-week regimen has been discontinued. -Safety is important: *Keep side rails up or use bed alarms. *Do not permit smoking. *Assist patient with ambulation (especially older adults). *Keep call light within reach. -Monitor for adverse effects. -Age-appropriate considerations -Monitor for therapeutic effects: *Increased ability to sleep at night *Fewer awakenings *Shorter sleep-induction time *Few adverse effects, such as "hangover" effects *Improved sense of well-being because of improved sleep *For muscle relaxants: decreased spasticity, decreased rigidity

Benzodiazepines: Mechanism of Action

-Depress CNS activity -Affect hypothalamic, thalamic, and limbic systems of the brain -Benzodiazepine receptors *Gamma-aminobutyric acid (GABA) -Do not suppress rapid eye movement (REM) sleep as much as barbiturates do -Do not increase metabolism of other drugs

Barbiturates: Contraindications

-Drug allergy -Pregnancy -Significant respiratory difficulties -Severe kidney or liver disease -Caution in older adults

Sedatives

-Drugs that have an inhibitory effect on the CNS to the degree that they reduce: *Nervousness *Excitability *Irritability

Muscle Relaxants: Adverse Effects

-Extension of effects on CNS and skeletal muscles *Euphoria *Lightheadedness *Dizziness *Drowsiness *Fatigue *Muscle weakness

Drug Profile: Diazepam (Valium)

-First clinically available benzodiazepine drug. It has varied uses *Treatment of anxiety *Procedural sedation and anesthesia adjunct *Skeletal muscle relaxation -Available in multiple forms: *Oral *Rectal *Injectable

Drug Profile: Nonbenzodiazepine: Eszopiclone (Lunesta)

-First hypnotic to be FDA approved for long-term use -Designed to provide a full 8 hours of sleep -Considered a short- to intermediate-acting agent -Patients should allot 8 hours of sleep time and should avoid taking hypnotics when they must awaken in less than 6 to 8 hours.

Drug Profile:Barbiturates

-First introduced in 1903; were the standard drugs for insomnia and sedation -Habit forming; low therapeutic index -Only a handful commonly used today partly because of the safety and efficacy of benzodiazepines

Miscellaneous Hypnotic Drugs

-Function like benzodiazepines but are chemically distinct *Ramelteon *Suvorexant (Belsomra) •Selective orexin receptor antagonist •Helps regulate sleep-wake cycle *Tasimelteon (Hetlioz) •Used only for disturbance of sleep-wake cycle in patients who are totally blind Limited use

Drug Profile: Orexin Receptor Antagonists

-Hypocretins -Neuropeptides that have been shown to regulate transitions between wakefulness and sleep -Promote cholinergic/monoaminergic neural pathways -Suvorexant (Belsomra) *First drug in this class *12-hour half-life *Adverse effects: drowsiness, headache, dizziness, diarrhea, dry mouth, cough, increased serum cholesterol Adverse effects more common in women

Drug Profile: Temazepam (Restoril)

-Intermediate-acting benzodiazepine -One of the metabolites of diazepam -Normally induces sleep within 20 to 40 minutes -Long onset of action, so it is recommended that patients take it about 1 hour prior to going to bed Still an effective hypnotic; however, it has been replaced by newer drugs

Drug Profile: Herbal Products: Kava

-Kava consists of the dried rhizomes of Piper methysticum. The drug contains kava pyrones (kawain). -Used to relieve anxiety, stress, and restlessness and to promote sleep -May cause temporary yellow skin discoloration (extended, continued intake) and visual disturbances -Potential interactions with alcohol, barbiturates, and psychoactive drugs -Contraindicated in liver disease, alcoholism, Parkinson's disease, pregnant women and breastfeeding, other conditions -Patient should not operate heavy machinery during use.

Benzodiazepines: Adverse Effects

-Mild and infrequent: *Headache *Drowsiness *Dizziness *Cognitive impairment *Vertigo *Lethargy *Fall hazard for older adults *"Hangover" effect or daytime sleepiness

Drug Profile: Midazolam (Versed)

-Most commonly used preoperatively and for moderate sedation -Causes amnesia and anxiolysis (reduced anxiety) as well as sedation -Normally administered by injection in adults -Liquid oral dosage form is also available for children.

Over-the-Counter Hypnotics

-Nonprescription sleeping aids often contain antihistamines, which have CNS depressant effect. -Doxylamine (Unisom) and diphenhydramine (Sominex), acetaminophen/diphenhydramine (Extra Strength Tylenol PM) -As with other CNS depressants, concurrent use of alcohol can cause respiratory depression or arrest.

Drug Profile: Cyclobenzaprine (Flexeril)

-Oral and extended release oral form (Amrix) -related to the tricyclic antidepressants -Centrally acting muscle relaxer -Most common used muscle relaxer -Can cause marked sedation

Drug Profile: Baclofen (Lioresal)

-Oral and injectable forms (titrated) -Treat chronic spastic muscular conditions *Implantable baclofen pump device

Barbiturates: Toxicity and Overdose

-Overdose frequently leads to respiratory depression and subsequent respiratory arrest. -Overdose produces CNS depression (sleep to coma and death). -Can be therapeutic *Anesthesia induction *Uncontrollable seizures: "phenobarbital coma"

Toxicity and Management of Overdose

-Primarily involve the CNS -No specific antidote or reversal -Best treated with conservative supportive measures -If taken along with other CNS depressants *Adequate airway must be maintained *EKG monitoring Fluid management to avoid crystalluria

Drug Profile: Phenobarbital

-Prototypical barbiturate -Long-acting -Uses: *Prevention of generalized tonic-clonic seizures and febrile convulsions *Hyperbilirubinemia in neonates *Rarely used as sedative *No longer recommended as a hypnotic

Drug Profie: Pentobarbital (Nembutal)

-Prototypical barbiturate -Long-acting drug -Uses: prevention of generalized tonic-clonic seizures and fever-induced convulsions, as well as treatment of hyperbilirubinemia in neonates -Rarely used today as a sedative and is no longer recommended to be used as a hypnotic drug

Barbiturates: Adverse Effects (Cont.)

-Reduced REM sleep, resulting in: *Agitation *Inability to deal with normal stress

Muscle Relaxants: Indications

-Relief of painful musculoskeletal conditions *Muscle spasms *Management of spasticity of severe chronic disorders (multiple sclerosis, cerebral palsy) -Work best when used along with physical therapy

Benzodiazepines: Indications

-Sedation -Sleep induction -Skeletal muscle relaxation -Anxiety relief -Anxiety-related depression -Treatment of acute seizure disorders -Treatment of alcohol withdrawal -Agitation relief -Balanced anesthesia -Moderate or conscious sedation

CNS Depressants

-Sedative-hypnotics: dose dependent -At low doses, calm the CNS without inducing sleep. -At high doses, calm the CNS to the point of causing sleep. -Classified into three main groups: *Barbiturates *Benzodiazepines *Miscellaneous drugs

Drug Profile: Nonbenzodiazepine: Zolpidem (Ambien)

-Short-acting nonbenzodiazepine hypnotic -Lower incidence of daytime sleepiness compared with benzodiazepine hypnotics -Ambien CR is a longer acting form with two separate drug reservoirs. -Somnambulation

Barbiturates: Mechanism of Action

-Site of action: brainstem (reticular formation) -By potentiating the action of GABA, nerve impulses traveling in the cerebral cortex are inhibited.

Drug Profile: Nonbenzodiazepine: Ramelteon (Rozerem)

-Structurally similar to the hormone melatonin: works as an agonist at melatonin receptors in the CNS -Technically, it is not a CNS depressant; used as hypnotic -Not classified as a controlled substance -Indicated for patients who have difficulty with sleep onset rather than sleep maintenance

Sleep

-Transient, reversible, and periodic state of rest *Decrease in physical activity and consciousness -Normal sleep is cyclic and repetitive. -A sleeping person is unaware of sensory stimuli within the immediate environment. -Sleep architecture *Rapid eye movement (REM) sleep *Non-REM sleep -REM interference -REM rebound

Barbiturates:Toxicity and Overdose (Cont.)

-Treatment of overdose *Symptomatic and supportive *Maintain adequate airway *Assisted ventilation or oxygen therapy *Fluids *Pressor support *Activated charcoal

Barbiturates: Indications

-Ultrashort acting *Anesthesia for short surgical procedures *Anesthesia induction *Control of seizures *Reduction of intracranial pressure in neurologic patients -Short acting *Sedation and control of seizures -Intermediate acting *Sedation and control of seizures -Long acting *Seizure prophyla

Drug Profile: Herbal Products: Valerian

-Used to relieve anxiety, restlessness, and sleep disorders -May cause CNS depression, hepatotoxicity, nausea, vomiting, anorexia, restlessness, insomnia -Many interactions, including with CNS depressants, MAOIs, phenytoin, warfarin, and alcohol -Contraindicated in cardiac and liver disease -Patient should not operate heavy machinery during use.

A patient is to receive diazepam 4 mg IV push as a "now" order for sedation. The medication is available for injection with a concentration of 5 mg/mL. How many milliliters will the nurse give for this dosage?

0.8 mL

The nurse will monitor the patient who is taking a muscle relaxant for which adverse effect? a. CNS depression b. Hypertension c. Peripheral edema d. Blurred vision

A

Benzodiazepines

A chemical category of drugs most frequently prescribed as anxiolytic drugs and less frequently as sedative-hypnotic agents. -Formerly the most commonly prescribed sedative-hypnotic drugs -Nonbenzodiazepines are currently more frequently prescribed. -Favorable adverse effect profiles, efficacy, and safety when used appropriately -Classified as either: *Sedative-hypnotic *Anxiolytic (medication that relieves anxiety) -Five benzodiazepines commonly used as sedative-hypnotic drugs

Barbiturate

A class of drugs used to induce sedation; chemical derivatives of barbituric acid

REM interference

A drug-induced reduction of REM sleep time.

The nurse is preparing to administer suvorexant (Belsomra) for sleep. The nurse will need to include which teaching about this drug? (Select all that apply.) a. This drug needs to be taken approximately 30 minutes before bedtime. b. It needs to be taken 2 hours before bedtime because of its slow onset. c. The patient needs to be cautioned about the high incidence of daytime somnolence and unconscious nighttime behaviors that may occur. d. This drug is less likely to interact with alcohol. e. This drug is available over the counter

A,C

Case Study: The patient tells the nurse that his friend has been taking valerian for a long period of time and that he isn't feeling so well. The patient asks the nurse what the adverse effects of valerian are. What adverse effect with valerian would the nurse discuss with the patient? A.Insomnia B.Yellow skin C.Bruising D.Increased appetite

ANS: A Adverse effects of valerian include CNS depression, hepatotoxicity, nausea, vomiting, anorexia, headache, restlessness, and insomnia

Which statement regarding muscle relaxants does the nurse identify as being accurate? A.Baclofen (Lioresal) is available as an injectable form for use with an implantable pump device. B.Cyclobenzaprine (Flexeril) produces little sedation. C.Patients taking muscle relaxants are at high risk of developing hypertension. D.Patients taking muscle relaxants should be told to stop taking the medication if they feel sleepy.

ANS: A Baclofen (Lioresal) is sometimes used in an injectable form. Cyclobenzaprine (Flexeril) often results in deep sedation and sleepiness. Patients taking muscle relaxants are at risk to develop hypotension; therefore, they should be taught safety measures to prevent falls. Sedation and sleepiness are common side effects of muscle relaxants; however, a patient should not abruptly discontinue use of the medication. Safety procedures should be followed to prevent accidents and falls.

When providing education to the patient on the use of a benzodiazepine medication, the nurse will include which information? A.These medications have little effect on the normal sleep cycle. B.Using this medication may cause drowsiness the next day. C.It is safe to drive while taking this medication. D.These drugs are safe to use with alcohol.

ANS: B Benzodiazepines interfere with REM sleep and may cause a "hangover" effect or next-day drowsiness. They should not be used with alcohol, and persons taking these drugs should not drive.

An older adult patient taking multiple medications has a barbiturate added to his medication regimen. When administering a barbiturate to an older adult, what should the nurse expect? A.A decrease in dosages of the other medications B.The patient will experience increased amounts of REM sleep C.To administer half of the usual dose of the barbiturate D.Total relief of anxiety

ANS: C Barbiturates are associated with an increased incidence of falls when used in older adults; therefore, the usual dose is reduced by half whenever possible. Because barbiturates stimulate the action of enzymes in the liver, drugs are usually broken down more quickly, sometimes requiring the dose to be increased. Patients taking barbiturates have decreased amounts of REM sleep and often experience paradoxical restlessness or excitement.

Barbiturates have a low therapeutic index. How does the nurse interpret this? A.Low doses are not therapeutic. B.The toxic range is narrow. C.They are habit forming. D.The effective, safe dosage range is narrow.

ANS: D Drugs with a low therapeutic index have only a narrow dosage range within which the drug is effective; above that range, they are rapidly toxic. Barbiturates are habit forming, but this is not related to the therapeutic index.

Case Study: A patient comes to the health care provider's office with complaints of feeling anxious and having difficulty sleeping. The patient tells the nurse that he wants to start taking valerian and Kava because he heard that these work well to help the problems he is experiencing. The patient has the following questions about valerian and Kava. What is the best response by the nurse? The patient asks, "Is there anything I have to worry about when taking Kava?" The best response by the nurse is: A."Kava is a natural product which has no side effects." B."You need a prescription to take Kava." C."No worries, Kava is recommended for patients with depression." D."It is best to inform your health care provider of any additional medication or supplements you plan to take to check for interactions that may be harmful."

ANS: D Even natural products have side effects. Side effects of Kava include skin discoloration, possible accommodative disturbances and pupillary enlargement, and scaly skin (with long-term use). Kava and other supplements are available without a prescription. Kava is contraindicated in patients with Parkinson's disease, liver disease, depression, or alcoholism; in those operating heavy machinery; and in pregnant and breastfeeding women. As with all medications and supplements, it is best to inform the health care provider to evaluate possible interactions among drugs and supplements taken

Benzodiazepines: Interactions

Azole antifungals, verapamil, diltiazem, protease inhibitors, macrolide antibiotics, grapefruit juice CNS depressants (alcohol, opioids) Olanzapine Rifampin Herbal Interactions Food-drug Interactions Opioids

A patient has been admitted to the emergency department because of an overdose of an oral benzodiazepine. He is very drowsy but still responsive. The nurse will prepare for which immediate intervention? a. Hemodialysis to remove the medication b. Administration of flumazenil c. Administration of naloxone d. Intubation and mechanical ventilation

B

Key Point: ________________ are commonly used for sedation, relief of anxiety, skeletal muscle relaxation, and treatment of acute seizure disorders

Benzodiazepines

An older adult has been given a benzodiazepine for sleep induction, but the night nurse noted that the patient was awake most of the night, watching television and reading in bed. The nurse documents that the patient has had which type of reaction to the medication? a. Allergic b. Teratogenic c. Paradoxical d. Idiopathic

C

The nurse is reviewing the prescriptions for a patient who will be discharged to home after being hospitalized for a hysterectomy. The patient asked for a sleeping pill, and the surgeon wrote a prescription for Ambien, 10 mg at bedtime as needed for sleep. What is the nurse's priority action at this time? a. Review the potential adverse effects with the patient. b. Suggest that the patient try drinking a glass of wine at bedtime. c. Contact the prescriber to question the dose of the Ambien. d. Assist the patient to find a pharmacy to fill the prescription on her way home.

C

Which considerations are important for the nurse to remember when administering a benzodiazepine as a sedative-hypnotic drug? (Select all that apply.) a. These drugs are intended for long-term management of insomnia. b. The drugs can be administered safely with other central nervous system depressants for insomnia. c. The dose needs to be given approximately 1 hour before the patient's bedtime. d. The drug is used as a first choice for treatment of sleeplessness. e. The patient needs to be evaluated for the drowsiness that may occur the morning after a benzodiazepine is taken

C,E

Barbiturates: Adverse Effects

Cardiovascular: vasodilation, HTN CNS: drowsiness, lethargy, vertigo Resp: respiratory depression and cough

A hospitalized patient is complaining of having difficulty sleeping. Which action will the nurse take first to address this problem? a. Administer a sedative-hypnotic drug if ordered. b. Offer tea made with the herbal preparation valerian. c. Encourage the patient to exercise by walking up and down the halls a few times if tolerated. d. Provide an environment that is restful, and reduce loud noises.

D

Benzodiazepines: Contraindications

Drug allergy Narrow-angle glaucoma Pregnancy

REM rebound

Excessive REM sleep following discontinuation of a sleep altering drug

Rapid eye movement (REM) sleep

One of the stages of the sleep cycle. Some of the characteristics of REM sleep are rapid movement of the eyes, vivid dreams, and irregular breathing

Key Point: Most sedative-hypnotic drugs suppress ___________ and should be used only for the recommended period of time.

REM sleep

Key Points: _________________ barbiturates include pentobarbital and secobarbital.

Short-acting

Benzodiazepines: Toxicity and Overdose

Somnolence Confusion Coma Diminished reflexes Do not cause hypotension and respiratory depression unless taken with other CNS depressants Treatment symptomatic and supportive *Flumazenil as an antidote

Non-rapid eye movement (non-REM) sleep

The largest portion of the sleep cycle. It has four stages and precedes REM sleep.

Sleep architecture

The structure of the various elements involved in the sleep cycle, including normal and abnormal patterns of sleep.

Key Term: Intermediate-acting benzodiazepines include:

alprazolam, lorazepam, and temazepam.

Key Point: Intermediate acting barbiturates include ___________________

butabarbital.

Key term: Long-acting benzodiazepines include:

clonazepam, diazepam, and flurazepam.

Key Term: Short-acting benzodiazepines include

eszopiclone, midazolam, ramelteon, triazolam, zaleplon, and zolpidem

Herbal supplements that interact with the benzodiazepines include ______________, which may also lead to further CNS depression

kava and valerian

Key Point: Long-acting barbiturates include

phenobarbital and mephobarbital

Key term: The orexin receptor antagonists, such as ____________________), are associated with more adverse effects in females.

suvorexant (Belsomra)