Pharm - Unit 2 - Chapter 12 - Central Nervous System Depressants and Muscle Relaxants

Key terms and prototypes

Barbiturates

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

Benzodiazepines

A chemical category of drugs most frequently prescribed as anxiolytic drugs and less frequently as sedative-hypnotic agents.

Hypnotics

Drugs that, when given at low to moderate dosages, calm or soothe the central nervous system without inducing sleep but when given at high dosages cause sleep.

Sedatives

Drugs that have an inhibitory effect on the central nervous system to the degree that they reduce nervousness, excitability, and irritability without causing sleep.

Sedative-hypnotics

Drugs that can act in the body either as sedatives or hypnotics.

Sleep

A transient, reversible, and periodic state of rest in which there is a decrease in physical activity and consciousness.

Cyclobenzaprine (Flexeril)

• Mechanism of action: Depressant effect on the CNS.

• Indications: Primarily used for the relief of painful musculoskeletal conditions such as muscle spasms.

• Routes of administration: Oral

• Adverse effects: Euphoria, lightheadedness, dizziness, drowsiness, fatigue, confusion, muscle weakness.

• Toxicity: No antidote for overdose. Adequate airway maintained.

• Contraindications: Drug allergy, severe renal impairment

• Drug interactions: Other depressants such as alcohol and benzodiazepines.

Temazepam (Restoril)

• Mechanism of action: Depressant effect on the CNS 

• Indications: Insomnia, sedation, relief of agitation, anxiety

• Routes of administration: Oral

• Adverse effects: drowsiness, nervousness, cognitive impairment, and lethargy.

• Toxicity: Overdose can lead to somnolence, confusion, diminished reflexes, and coma. Flumazenil, an antidote, can be used to acutely reverse the sedative effects

• Contraindications: Drug allergy, narrow-angle glaucoma, and pregnancy.

• Drug interactions: Other depressants such as alcohol, opioids, and muscle relaxants. Also kava and valerian.

Diazepam (Valium)

• Mechanism of action: Depressant effect on the CNS 

• Indications: Anxiety, sedation, relief of agitation, anxiety

• Routes of administration: Oral, rectal, injectable

• Adverse effects: drowsiness, nervousness, cognitive impairment, and lethargy.

• Toxicity: Overdose can lead to somnolence, confusion, diminished reflexes, and coma. Flumazenil, an antidote, can be used to acutely reverse the sedative effects

• Contraindications: Drug allergy, narrow-angle glaucoma, and pregnancy.

• Drug interactions: Other depressants such as alcohol, opioids, and muscle relaxants. Also kava and valerian.

Zolpidem (Ambien)

• Mechanism of action: Short acting nonbenzodiazepine

• Indications: Insomnia

• Routes of administration: Oral

• Adverse effects: Sleep-walking

• Toxicity: Overdose can lead to somnolence, confusion, diminished reflexes, and coma. Flumazenil, an antidote, can be used to acutely reverse the sedative effects

• Contraindications: Drug allergy

• Drug interactions: Other depressants such as alcohol, opioids, and muscle relaxants. Also kava and valerian.

Phenobarbital

• Mechanism of action: Depressant effect on the CNS

• Indications: Ultrashort acting anesthesia, control of convulsions,

• Routes of administration: Oral, IV

• Adverse effects: Drowsiness, lethargy, hangover, and paradoxical restlessness or excitement

• Toxicity: For overdose, maintenance of an adequate airway, assisted ventilation, and oxygen administration if needed, along with fluid and pressor support as indicated.

• Contraindications: Drug allergy, pregnancy, respiratory
  difficulty, kidney or liver disease

• Drug interactions: Can cause other drugs to be metabolized more quickly, which usually shortens their duration of action. Other CNS depressants.