Transcript Central Nervous System Stimulants, Anticonvulsants, and

Anticonvulsants and
Antiparkinsonism
Drugs
Chapter 5
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Anticonvulsant Drugs
 Prevent convulsions or seizure
 Partial or focal seizure
 Arise from a localized area in the brain and cause specific
symptoms
 Can spread to the entire brain and cause a generalized
seizure
 Generalized seizure
 Absence
 Myoclonic
 Tonic-clonic
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Psychomotor Seizures
 Occur most often in children.
 Aura may precede the event.
 Most common motor symptom is
drawing or jerking of the mouth and
face.
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Epilepsy
 Permanent, recurrent seizure disorder
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Actions of Anticonvulsants
 Reduce the excitability of the neurons of the brain
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Uses of Anticonvulsants
 Used to control seizure activity, but often a patient will
not respond well to one drug, and another drug or a
combination will be tried
 Dose adjustments often are needed to find the correct
level of control
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Adverse Reactions of Anticonvulsants
 The most common adverse reaction is sedation.
 Can range from drowsiness to somnolence
 Agitation rather than sedation may occur in some
patients.
 Adverse reactions may be reduced or eliminated with
therapy or a decrease in dose.
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Adverse Reactions of Anticonvulsants
 Benzodiazepines also can cause sedation
 Adverse reactions can be dose dependent and include:

Anorexia

Constipation or diarrhea
 A health care provider should be notified if:

Unusual bruising or bleeding

Fever

Sore throat

Rash

Mouth ulcers
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Adverse Reactions of Anticonvulsants
 Hydantoins (phenytoin) are the most commonly
prescribed anticonvulsants, and adverse effects include:
 Nystagmus
 Ataxia
 Slurred speech
 Mental changes
 Gingival hyperplasia
 Blood dyscrasias
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Adverse Reactions of Anticonvulsants
 Succinimides often cause gastrointestinal symptoms
 Other adverse reactions:

Mental confusion

Personality changes

Pruritus

Urticaria

Urinary frequency

Weight loss

Hematologic changes
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Adverse Reactions of Anticonvulsants
• Miscellaneous anticonvulsants
– Lamotrigine – severe and potentially fatal rash
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Contraindications, Precautions, and
Interactions of Anticonvulsants
 Care should be taken with barbiturate use in patients
with liver, kidney, or neurologic disorders or pulmonary
disease.
 Barbiturates are used with caution in hyperactive
children.
 Barbiturates will have an additive effect if used with
alcohol or other CNS depressants.
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Contraindications, Precautions, and
Interactions of Anticonvulsants
 Care should be taken with benzodiazepine use in patients
with psychoses, acute narrow angle glaucoma, liver or
kidney disease, or neurologic disorders.
 Benzodiazepines should be used with caution in elderly or
debilitated patients.
 Alcohol and other CNS depressants can also have an
additive effect when used with benzodiazepine.
 Benzodiazepines interact with a number of other
medications.
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Contraindications, Precautions, and
Interactions of Anticonvulsants
 Hydantoins are contraindicated in patients with:
 Sinus bradycardia
 Sinoatrial block
 Second- and third-degree AV block
 Adams-Stokes syndrome
 Liver disease
 Pregnancy and lactation
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Contraindications, Precautions, and
Interactions of Anticonvulsants
 Hydantoins have an additive effect with alcohol and
other CNS depressants.
 Phenytoin should be used with caution in patients
with:
 Hypotension
 Severe myocardial insufficiency
 Hepatic impairment
 Phenytoin interacts with many different drugs.
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Contraindications, Precautions, and
Interactions of Anticonvulsants
 Succinimides are contraindicated in patients with bone
marrow depression or hepatic or renal impairment and
during lactation.
 Additive effect with alcohol, antidepressants, and
narcotics
 Concurrent administration with other anticonvulsants
may require a dosage adjustment.
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Contraindications, Precautions, and
Interactions of Anticonvulsants
 Miscellaneous anticonvulsants are used cautiously in
patients with:
 Glaucoma or increased intraocular pressure
 History of cardiac, renal, or liver dysfunction or
psychiatric disorders
 Carbamazepine
 Contraindicated in patients with bone marrow
suppression or hepatic or renal impairment
 Interacts with several other drugs
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Contraindications, Precautions, and
Interactions of Anticonvulsants
 Valproic acid
 Contraindicated in patients with renal impairment
 Oxcarbazepine
 May exacerbate dementia
 Lamotrigine
 Interacts with valproic acid
 Miscellaneous anticonvulsants have an additive effect
when combined with CNS depressants and alcohol.
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Patient Management Issues
with Anticonvulsants
• Dosage adjustments may be necessary during initial
treatment.
• Dosage adjustments are based on patient’s response and
adverse reactions.
• Medication must be taken as prescribed.
– Do not omit or miss a dose.
– Do not abruptly discontinue.
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Educating the Patient and Family
About Anticonvulsants
 Family may be the first to witness seizures.
 Keep a record of all seizures.
 Anticonvulsants control, but do not cure, epilepsy.
 Support groups may be available.
 Safety concerns may need to be addressed, such as
driving or working conditions.
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Educating the Patient and Family
About Anticonvulsants
 Do not increase, decrease, or omit dose.
 Blood levels may need to be monitored.
 Do not abruptly discontinue.
 These drugs may cause drowsiness or dizziness.
 Avoid alcohol.
 Carry identification indicating drug use and type of
seizures.
 Do not use other medications without consulting a
health care provider.
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Educating the Patient and Family
About Anticonvulsants
 Hydantoins
 Brush and floss
 Make regular dental appointments for oral
examination and care
 Take with food
 Shake the suspension before use
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Educating the Patient and Family
About Anticonvulsants
 Succinimides
 Take with food or milk to avoid gastrointestinal
upset.
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Antiparkinsonism Drugs
• Parkinson disease – “paralysis agitans” is a degenerative
disorder of the central nervous system
• Caused by a deficiency of dopamine and an excess of
acetylcholine within the central nervous system
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Actions of Dopaminergic Drugs
 Affect the dopamine content of the brain
 Dopamine is not effective when given orally since it does
not cross the blood-brain barrier.
 Levodopa will cross the blood-brain barrier and then
converts to dopamine.
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Uses of Dopaminergic Drugs
 Treat signs and symptoms of parkinsonism
 Levodopa is the gold standard.
 Carbidopa is always given with levodopa.
 Amantadine is less effective than levodopa but more
effective than anticholinergics.
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Adverse Reactions of Dopaminergic
Drugs
 Choreiform movements
 Dystonic movements
 Mental changes:
 Depression
 Psychotic episodes
 Paranoia
 Suicidal tendencies
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Off–On Phenomenon
• Patient may suddenly alternate between improved clinical
status and loss of therapeutic effect
• Associated with long-term levodopa treatment
• “Drug holiday” may be needed
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Contraindications, Precautions, and
Interactions of Dopaminergic Drugs
 Levodopa is contraindicated in patients with narrowangle glaucoma and taking MAOIs.
 Levodopa interacts with many different drugs.
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Contraindications, Precautions, and
Interactions of Dopaminergic Drugs
 Levodopa is used cautiously in patients with:
 Cardiovascular disease
 Bronchial asthma
 Emphysema
 Peptic ulcer disease
 Renal or hepatic disease
 Psychosis
 Lactating patients
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Contraindications, Precautions, and
Interactions of Dopaminergic Drugs
 Selegiline is used cautiously in patients with psychosis,
dementia, or excessive tremor.
 Selegiline increases the effectiveness of levodopa when
they are taken together.
 Selegiline interacts with fluoxetine.
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Contraindications, Precautions, and
Interactions of Dopaminergic Drugs
 Amantadine is used cautiously in patients with:
 Seizure disorders
 Hepatic disease
 Psychosis
 Cardiac disease
 Renal disease
 Amantadine interacts with numerous other drugs.
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Actions and Uses of Anticholinergic
Drugs
 Inhibit acetylcholine in the CNS
 Used as adjunctive therapy in all
forms of parkinsonism
 Control drug-induced
extrapyramidal disorders
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Adverse Reactions of Anticholinergic
Drugs
 Dry mouth
 Blurred vision
 Dizziness
 Mild nausea
 Nervousness
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Contraindications, Precautions, and
Interactions of Anticholinergic Drugs
 Contraindicated in patients with:

Glaucoma

Pyloric or duodenal obstruction

Peptic ulcers, prostatic hypertrophy

Achalasia

Myasthenia gravis

Megacolon
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Contraindications, Precautions, and
Interactions of Anticholinergic Drugs
 Use with caution in:

Older adults

Cardiovascular disease (tachycardia, cardiac
arrhythmias, hypertension, hypotension)

Urinary retention

Decreased liver or kidney function

Obstructive disease of the gastrointestinal tract
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Actions and Uses of COMT Inhibitors
 Catechol-O-methyltransferase (COMT) inhibitor
 Thought to prolong the effect of levodopa by blocking the
enzyme COMT, which would otherwise eliminate the
dopamine
 Used as an adjunct to levodopa/carbidopa
 Easily crosses blood-brain barrier
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Adverse Reactions of COMT Inhibitors
 Disorientation and confusion
 Light-headedness
 Dizziness
 Dyskinesias
 Hyperkinesias
 Nausea and vomiting
 Hallucinations
 Fever
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Contraindications, Precautions, and
Interactions of COMT Inhibitors
 Contraindicated during lactation
 Associated with liver damage and liver failure
 Used with caution in patients with hypertension,
hypotension, and decreased hepatic or renal function
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Actions and Uses of Dopamine Receptor
Agonists
 Exact mechanism not understood
 May mimic the effects of dopamine in the brain
 Used for Parkinson disease
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Adverse Reactions of Dopamine Receptor
Agonists
 Nausea
 Dizziness
 Postural hypotension
 Hallucinations
 Somnolence
 Vomiting
 Confusion
 Visual disturbances
 Abnormal involuntary movements
 Headache
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Contraindications, Precautions, and
Interactions of Dopamine Receptor
Agonists
 Contraindicated in patients with severe ischemic heart disease
or peripheral vascular disease
 Use with caution in patients with:

Dyskinesia

Orthostatic hypotension

Hepatic or renal impairment

Cardiovascular disease

History of hallucinations or psychosis
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Contraindications, Precautions, and
Interactions of Dopamine Receptor
Agonists
 Increased risk of CNS depression
 Increase the effects of levodopa when coadministered
 Interact with ciprofloxacin and phenothiazines
 Pramipexole interacts with a number of medication
 Ropinirole interacts with estrogens
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Patient Management Issues with
Antiparkinsonism Drugs
 History obtained from patient can be unreliable.
 Baseline physical assessment needed.
 Drug therapy needs careful monitoring.
 Some patients communicate poorly.
 Observe the patient for outward changes that may
indicate adverse reactions.
 Symptoms may be communicated through changes in
posture and facial expression.
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Educating the Patient and Family
About Antiparkinsonism Drugs
 The home environment must be examined to make it
least likely to result in accidents or falls.
 Medication should be taken as prescribed.
 Sudden changes in behavior can indicate hallucinations,
depression, or other psychotic episodes.
 Observe the patient for adverse reactions.
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