Lecture 7 Pharmacology

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Lecture 7 Pharmacology

• Hypnotic and Sedatives Con't
• Muscle Relaxants
• Antiparkinsonian
• Anticonvulsants

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Non-Benzodiazepines Non-Barbiturates

• Act as hypnotics for insomnia
• For short term use
• Lose effectiveness after 2 weeks

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Mechanism of Action

• Not completely known
• Similar to barbiturates
• Depression effect

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Therapeutic Use - Example Chloral hydrate
Placidyl

• insomnia
• sedative for preop
• sedation for procedures
• EEG for children

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Drug Interactions

• Other CNS depressants
• may cause very serious resp depression
• or even death

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Adverse Reactions

• GI -N/V, irritation
• CNS- hangover
• Resp - depression
• Prolonged use- tolerance, dependence, withdrawal
• Unpredictable- rash, allergic reaction
• Idiosyncratic- excitement, hysteria

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Nursing Implications

• Similar to barbiturates in potential toxicity
• Contraindicated- renal or hepatic dysfunction,
  drug abuse
• Do not give liquid if Hx of gastric ulcers
• Decrease dose in elderly
• Caution in depressed or emotional disorders

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Activity Thread- Skeletal muscle relaxants

• Treat acute painful conditions with
• muscle spasticity
• multiple sclerosis
• cerebral palsy
• CVA
• spinal cord injury

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Central Acting - Flexeril or Robaxin

• Act in spinal cord
• Cause CNS depression
• Used with rest Physical Therapy

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Drug Interactions

• Synergetic Effect with other CNS depressants
• Added depression with ETOH
• MAO inhibitors, psychiatric antidepressants
• Antihypertensives (have less effect)
• Cholinergic blockers (increase anticholinergic
  effect

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Adverse Reactions

• Drowsiness, dizziness
• N/V/D abd. distress, constipation
• Resp depression, hypotension

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Nursing Implications

• Warn to not drive or use machinery
• Avoid ETOH, CNS depressants
• caution with Hx. urine retention, cardiac disease
• not to pt with glaucoma

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Peripherally Acting Muscle Relaxants

• Dantrium - similar effect to central acting Rx
• Works directly on muscle contractile mechanism
• inhibits Ca release from muscles
• Used with all types of spastically
• Interact with CNS depressants

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Adverse Reactions

• muscle weakness
• lightheadedness
• visual and speech disturbances
• urine retention, frequency or incontinence
• Idiosyncratic reaction hepatitis

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Nursing Implications

• Not for use in pt with liver dysfunction
• Caution in cardiac or lung dysfunction
• Warn pt about weakness, drowsiness, dizziness
• Obtain baseline of liver function

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Other Skeletal Muscle Relaxants

• Benzodiazepines - Diazepam Baclofen
• Drug of choice for treatment of spasms
• Enhances neurotransmitter GABA (gamma
  aminobutyric acid)
• inhibitory effect on muscle contraction
• Limited by CNS effects tolerance development

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Parkinson's Disease

• Masklike face
• Tremors stooped
  posture
• 
  rigidity
• short shuffle hip
  knees
• steps
  flexed

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Antiparkinsonian Agents/ Anticholinergic Agents

• Parkinson's Disease
• affects voluntary control of motor function
• decrease in dopamine (inhibitory
  neurotransmitter)
• increased acetylcholine (excitatory transmitter)
• tremors
• akinesia
• rigidity
• Therapy aims to replace dopamine or decrease
  acetylcholine

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Anticholinergics - Cogentin or Benadryl

• Counter acts Cholinergic action of acetycholine
• Used in early stages of Parkinson's
• Interact with antipsychotics levodopa

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Dopamine -Acetylcholine
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Anticholinergic Effects

• Restless, Drowsiness
• Confusion
• Blurred Vision
• Tachycardia
• Dry Bronchial Secretion
• Decreased Sweating
• Constipation
• Urine retention

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Adverse Reaction usually an extension of effects

• CNS - confusion, agitation
• Ocular dilation (poor vision)
• Oral and Skin - dry
• Cardiac palpitations tachycardia
• GI - constipation
• GU urine retention

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Nursing Implications

• Do not give to pt with glaucoma
• Caution in pt with enlarged prostate
• Caution in elderly or demented
• Caution in pt with tachycardia, CAD, CHF
• Caution in pt with ulcers (give with meals)
• Teach pt may cause drowsiness, visual changes
• Avoid heat and sun
• Do not use OTC (cough/cold prep, diet aid, Nodoz)

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Dopaminergic Agents

• Levodopa -metabolic precursor to dopamine
• crosses blood brain barrier
• converted into dopamine
• Used in pt not responsive to anticholinergics

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Dopaminergic Agents

• Symmetrel
• Antiviral
• Increases dopamine release
• or blocks its reuptake

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Drug interactions

• Most serious is Levodopa with MAO inhibitors
• May cause Hypertensive Crisis
• Food with Levodopa amino acid decreases effect
• May need to decrease protein intake or take on
  empty stomach
• Symmetrel -may cause skin rash

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Nursing Implications

• Do not use symmetrel on pt dermatitis
• Levodopa - not with pt with glaucoma
• HX of ulcer disease (give with meals)

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Anticonvulsants

• Treats seizures from epilepsy
• Seizures from head injuries
• Petite-mal and Grand-mal

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Hydantoins- Dilantin

• most common Rx for seizure control
• 90 protein bound
• metabolized by hepatic enzymes

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Mechanism of Action

• primary site in motor cortex
• inhibits spread of seizure activity
• some antiarrythmia properties similar to lidocaine

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Therapeutic Use

• Rx of choice for complex partial (psychomotor)
• Tonic-clonic seizures

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Drug Interactions

• MANY!!
• All highly protein bound drugs are altered
• coumadin, corticosteroids
• theophyline, thyroid

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Adverse Drug Reactions

• CNS - slurred speech, confusion, drowsiness,
  ataxia
• GI N/V epigastric pain, anorexia, gingival
  hyperplasia

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Adverse Drug Reactionscontinued

• Cardiac - decreased A/V conduction, dec.. P, BP,
  arrest
• Unpredictable- rash, liver necrosis,
  thrombocytopenia

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Nursing Implications

• Do not give if bradycardic, SA block
• Caution in blood dyscrasias, hypotensive or
  cardiac insufficiency
• Caution in renal dysfunction, alcoholism
• Not safe during pregnancy (birth defects)
• Check serum levels periodically
• Give oral dose with meals to decrease GI
  irritation
• Dental care essential
• Do not mix with RX

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General teaching

• Do not discontinue
• Avoid hazardous machinery
• Family how to care for pt with seizure
• No OTC, ETOH
• Follow up with MD

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Barbiturates

• Limit seizure activity by increasing threshold
  for motor cortex stimuli
• Used for partial, tonic-clonic febrile seizures
• Dose for seizure control is less than for
  hypnotic
• Interacts with MANY Rx

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Adverse Reactions

• CNS - dose related - drowsiness, lethargy,
  confusion
• GI - N/V
• Laryngospasm, depressed respiration
• hypotension, pupil constriction, oliguria,
  circulatory collapse
• anemias

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Nursing Implications

• Caution with resp, cardiac, hepatic, anemia
• Bedrails up for safety (Pad rails)
• Check serum level
• Schedule IV controlled

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Iminostilbenes - Tegretol

• Action similar to dilantin - inhibits spread of
  seizure activity
• Used for tonic-clonic seizures
• Interacts to induce enzyme activity

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Adverse Reactions

• Drowsy, double vision
• Altered blood pressure
• Anticholinergic- urine retention, constipation,
  glaucoma
• anemias

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Nursing Implications

• Do not give with MAO inhibitors (hyperpyretic
  crisis)
• Caution in cardiac, hepatic, renal disease
• Take with meals

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Benzodiazepines - Valium

• Not for long term use
• IV status epilepticus -short term effect
• Interact with CNS depressants

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Adverse Reactions

• Neuro- drowsiness, confusion, dizzy, ataxia
• Cardiac and respiratory depression
• Rash, hepatomegaly
• Thrombocytopenia

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Nursing Implications

• DO not give if pregnant, hi BP, Liver Disease
• Caution in drug abuse, ETOH intox.
• caution in elderly, children
• If OD use Romazicon - antidote
• Do not mix with other Rx or IV

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Valproic Acid (Depakene)

• Used in clonic-tonic and petit mal seizures
• adverse reactions - platelet aggregation
  thrombocytopenia
• young children - fatal liver toxicity

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Nursing Implications

• Caution in liver disease
• Check serum levels
• Monitor liver function tests
• Teach pt to report sx liver dysfunction

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Remember - All Anticonvulsants

• Major side effects- Liver Toxicity
• Thrombocytopenia