objective 2.1 (2) Flashcards by Kaitlyn Dominie

Drugs that stimulate a specific area of the brain or spinal cord
Neurons contain receptors for excitatory neurotransmitters, including dopamine (dopaminergic drugs), norepinephrine (adrenergic drugs), and serotonin (serotonergic drugs).
Sympathomimetic drugs

CNS stimulants

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what are the 3 ways CNS stimulants are classified?

Chemical structural similarities- major chemical classes of CNS stimulants include amphetamines, serotonin agonists, sympathomimetics, and xanthines
Site of therapeutic action in the central nervous system (CNS)
Or into the 5 Major therapeutic uses: anti–attention-deficit/hyperactivity disorder, antinarcoleptic, anorexiant, antimigraine, and analeptic drugs

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Most common neurodevelopmental disorder in children, affecting 3 to 10% of school-age children
Boys affected two to nine times more often than girls are
May be related to the underdiagnosing in girls
Primary symptom of attentiondeficit/hyperactivity disorder (ADHD): inappropriate ability to maintain attention span, or hyperactivity and impulsivity
Drug therapy for both childhood and adult ADHD is the same.

ADHD

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Incurable neurological condition in which patients unexpectedly fall asleep in the middle of normal daily activities

narcolepsy

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sudden acute skeletal muscle weakness
Triggered by strong emotion

cataplexy

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what are the drugs for ADHD and narcolepsy

Amphetamines
Nonamphetamine stimulant
Nonstimulant drugs

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Stimulate areas of the brain associated with mental alertness
CNS effects
Mood elevation or euphoria
Increased mental alertness and capacity for work
Decreased fatigue and drowsiness
Prolonged wakefulness
Respiratory effects
Relaxation of bronchial smooth muscle
Increased respiration
Dilation of pulmonary arteries

amphetamines

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what are the AE of amphetamines?

Wide range; dose related
Tend to “speed up” body systems
Common adverse effects include:
Palpitations, tachycardia, hypertension, angina, anxiety, insomnia, headache, tremor, nausea, vomiting, diarrhea, dry mouth, increased metabolic rate, others
Contraindications to using amphetamine and nonamphetamine stimulants include known drug allergy and cardiac structure abnormalities.

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Approved for treating ADHD in children older than 6 years of age and in adults
Health Canada has issued a warning describing cases of suicidal thinking and behaviour in small numbers of adolescent patients receiving this medication.

atomozetine hydrochloride

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First prescription drug indicated for ADHD-most widely prescribed, Also used for narcolepsy
Extended-release dosage forms: Ritalin SR®, Concerta®, Biphentin®

methylphenidate hydrochloride

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Use: improvement of wakefulness in patients with excessive daytime sleepiness associated with narcolepsy and with “shift work” sleep disorder
Less potential for misuse than amphetamines and methylphenidate
Available with a prescription

modafinil

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Used to treat obesity
Effectiveness has not been proven
None currently available in Canada to treat obesity
Related drug, orlistat (Xenical® ), a nonstimulant drug to treat obesity
Inhibits absorption of caloric intake from fatty foods
Adverse effects: Headache, Upper respiratory infection, Gastrointestinal (GI) distress, fecal incontinence

anorexiants

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Common type of recurring headache, usually lasting from 4-72hrs
Typical features: pulsatile quality with paim that worsens with each pulse
Most commonly unilateral but may occur on both sides of the head
Associated symptoms: nausea, vomiting, photophobia (patient avoids light), phonophobia patient avoids sounds
Aura

migraine

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Stimulate 5HT receptors in cerebral arteries, causing vasoconstriction and reducing headache symptoms
Reduce the production of inflammatory neuropeptides
Reduce the production of inflammatory neuropeptides
Contraindications to triptans include known drug allergy and the presence of serious cardiovascular disease because of the vasoconstrictive potential of these meds

SSRAs

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were the mainstay of treatment of mirgraine headaches but have been replaced by triptans for first-line therapy
Obtained from a fungus and cause vasoconstriction of BV in the brain and carotid arteries
Constrict or narrow BV in the brain
Contraindications to ergot alkaloids include uncontrolled HTN, cerebral, cardiac or peripheral vascular disease, dysrhythmias, glucoma and CAD

ergot alkaloids

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Used less frequently
Still used for neonatal apnea, and postoperative respiratory depression
Examples:
Methylzanthines, such as aminophylline, theophylline, and caffeine
Indicated: primary to stimulate respirations
Contraindicated: drug allergy, peptic ulder disease and serious cardiovascular condition

analeptics

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what are the AE of analeptics?

Vagal: stimulation of gastric secretions, diarrhea, and reflex tachycardia
Vasomotor: flushing, sweating
Respiratory: elevated respiratory rate
Musculoskeletal: muscular tension and tremors

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Inhibit phosphodiesterase, leading to buildup of cyclic adenosine monophosphate

methylxanthines

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Stimulant effects of caffeine are attributed to it antagonism of adenosine receptors
Adenosine is associated with sleep promotion
Found in: OTC drugs’ combo presription durgs; foods and beverages
Use with caution in pts with a history of: peptic ulcer, recent myocardial infarction, dysrhythmias
Available in oral form

caffeine

Enhances mental alertness, improves memory or reduced symptoms in people with dementia
Avoid using with warfarin, aspirin

ginko biloba

Improves mental function and concentration
Avoid using with drugs for diabetes (insulin, oral drugs), MAOI’s

ginseg

Stimulates nervous system, suppresses appetite
Avoid with adenosine, quinolones, oral contraceptives, B-blockers, iron etc

guarana

Brief episode of abnormal electrical activity in nerve cells of the brain, which may or may not lead to a convulsion

seizure

Involuntary spasmodic contractions of any or all voluntary muscles throughout the body, including skeletal, facial, and ocular muscles

convulsion

Chronic, recurrent pattern of seizures

epilepsy

Cause cannot be determined. Roughly 50% of epilepsy cases

primary (idiopathic)

Distinct cause is identified. Trauma, infection, cerebrovascular disorder

secondary (symptomatic)

what are the classifications of epilepsy?

Generalized onset seizures Tonic-clonic seizures Atonic seizures Partial onset seizures (Focal Onset) Simple Complex Secondary generalized tonic-clonic Unclassified seizures

originate in a localized or focal region of the brain

partial onset seizures

Multiple seizures occur that last 5 minutes or longer of continuous or electrographic seizure activity or recurrent seizure activity without recovery between seizures Result: hypotension, hypoxia, brain damage, and possibly death True medical emergency Diazepam (Valium) – immediate treatment for status epilepticus

status epilepticus

Also known as anticonvulsants Difference between epilepsy and convulsions Goals of therapy: To control or prevent seizures while maintaining a reasonable quality of life & To minimize adverse effects and drug-induced toxicity Antiepileptic drug (AED) therapy is usually lifelong, Combination of drugs may be used Single-drug therapy is started before multiple-drug therapy is tried. Serum drug concentrations must be measured: Therapeutic drug monitoring

antiepileptic drugs

what are the antiepileptic drugs?

Barbiturates Hydantoins Iminostilbenes plus valproic acid Second- and third-generation antiepileptics

Primidone is metabolized in the liver to phenobarbital. Common adverse effect is sedation. Therapeutic effects: serum drug levels of 15 to 40 mcg/mL Contraindications: known drug allergy, porphyria, liver or kidney impairment, respiratory illness Adverse effects: cardiovascular, central nervous system (CNS), gastrointestinal (GI), and dermatological reactions

barbiturates: phenobarbital & primidone

Phenytoin (Dilantin® ) has been used as a first-line drug for many years and is the prototypical drug. Adverse effects: gingival hyperplasia, acne, hirsutism, Dilantin facies, and osteoporosis Contraindicated in known allergy, and heart conditions Can interact with other meds due to it being highly bound to plasma proteins and competes with other highly protein bound medications for binding sites. And it induces liver microsomal enzymes Therapeutic drug levels are usually 10 to 20 mcg/mL. Intravenous (IV) administration Very irritating to veins, Slow IV directly into a large vein through a large-gauge (20-gauge or larger) venous catheter, Diluted in normal saline for IV infusion, Filter must be used, Saline flush

hydantoins

The second most commonly prescribed antiepileptic drug in Canada after phenytoin 1 st line trmt for focal seizures and generalized tonic clonic seizures. It can worsen myoclonic or absence seizures Contraindicated if drug allergy, and bone marrow depression Associated with autoinduction of hepatic enzymes Numerous Adverse reactions/Drug interactions

iminostilbenes: carbamazepine

Chronic, progressive, neurodegenerative disorder Affects dopamine-producing neurons in the brain Caused by an imbalance of two neurotransmitters Dopamine & Acetylcholine (ACh) Symptoms occur when about 80% of the dopamine stored in the substantia nigra of the basal ganglia is depleted. Symptoms can be partially controlled as long as there are functioning nerve terminals that can take up dopamine. Classic symptoms include: Bradykinesia “TRAP” Tremor, Rigidity, Akinesia , Postural instability A progressive condition with carious types of motor complications that can occur Rapid swings in response to levodopa occur (“on–off phenomenon”) Parkinson’s disease (PD) worsens when too little dopamine is present. Dyskinesia occurs when too much dopamine is present. “Wearing-off phenomenon”- end of dose PD-associated dementia

parkinsons disease

Difficulty in performing voluntary movements

dyskinesia

irregular, spasmodic, involuntary movements of the limbs or facial muscles

chorea

abnormal muscle tone leading to impaired or abnormal movements

dystonia

what are the drug actin dopaminergic drugs?

1) nondopamine dopamine receptor agonists Further subdivided into the Ergot derivative: bromocriptine Nonergot drugs pramipexole dihydrochloride monohydrate (Mirapex) and ropinirole (Requip) 2) dopamine replacement drugs

biological precursor of dopamine required by the brain for dopamine synthesis is able to cross the blood–brain barrier, and then it is converted to dopamine. However, large doses of levodopa needed to get dopamine to the brain also cause adverse effects (confusion, GI distress, hyoptension etc)

levodopa

is given with levodopa. Carbidopa does not cross the blood–brain barrier and prevents levodopa breakdown in the periphery and allows for smaller doses of levodopa to be used. Resulting in fewer unwanted adverse effects. As a result, more levodopa crosses the blood–brain barrier, where it can be converted to dopamine.

carbidopa

Carbidopa alone: adjunct to treat nausea associated with Sinemet Sinemet CR: increases “on” time and decreases “off” time Carbidopa–levodopa is best taken on an empty stomach; to minimize GI adverse effects, it can be taken with food. Adverse effects: cardiac dysrhythmias, hypotension, chorea, muscle cramps, GI distress Contraindicated in cases of primary angleclosure glaucoma (increases IOP), not to be used in pts with undiagnosed skin condition because both drugs car activate malignant melanoma. Use cautiously in patients with open-angle glaucoma Drug interactions tricyclic antidepressant, nonselective MAOIs, benzodiazepines, antipsychotics Pyridoxine Hcl (Bitamin B6), reduces the effectiveness of levodopa-carbidopa (may need dose adjusted)

levodopa-carbidopa therapy (sinemet)

breaks down catecholamines (dopamine, norepinephrine and epinephrine) in the CNS, primarily in the brain

MAO

are selective MAO-B inhibitors. Cause an increase in levels of dopaminergic stimulation in the CNS Do not elicit the “cheese effect” of the nonselective MAOIs used to treat depression (if 10 mg or less is used) Rasagiline is the newest antiparkinsonian drug. Once a day trmt in early stages of disease. Approved as a monotherapy for PD, Selegiline is normally used as an adjunctive therapy in combo with other drugs (ie: levodopa-carbidopa). Contraindications Known drug allergy Selegiline interacts with meperidine (Demerol) Adverse effects: dizziness, insomnia, hallucinations, depression etc Table 16.3

selegiline hydrochloride and rasagiline mesylate

amantadine hydrochloride: First recognized as an antiviral drug used for treatment of influenza; Indirect acting MOA Causes release of dopamine and other catecholamines from their storage sites in the presynaptic fibres of nerve cells within the basal ganglia that have not yet been destroyed by the disease process Blocks the reuptake of dopamine into the nerve fibres Result: higher levels of dopamine in the synapses between nerves and improved dopamine neurotransmission between neurons Indications: Used early in the course of the disease but can be used in mod to adv stages. Usually effective for only 6 to 12 months Used to treat dyskinesia associated with carbidopa–levodopa Adverse effects associated with amantadine are relatively mild and include dizziness, insomnia, and nausea. Drug interactions: increased anticholinergic adverse effects when given with anticholinergic drugs Contraindicated: known drug allergy

dopamine modulator

block the effects of Ach. Used to treat muscle tremors and muscle rigidity associated with PD These two symptoms are caused by excessive cholinergic activity. Does not relieve bradykinesia (extremely slow movements). Acetylcholine is responsible for causing SLUDGE: increased salivation, lacrimation (tearing of the eyes), urination, diarrhea, increased GI motility, and possibly emesis (vomiting). Anticholinergics have the opposite effects: dry mouth or decreased salivation, urinary retention, decreased GI motility (constipation), dilated pupils (mydriasis), and smooth muscle relaxation.

anticholinergic therapy