Exam 2 Flashcards
How does histamine impact mast cells?
- vascular / mucosal permeability
- pruritus (itching)
- stimulation of irritant receptors
How do kinins impact mast cells?
vascular permeability
List mediators that impact mast cells
- HISTAMINE
- neutrophil & eosinophil chemotactic factor
- kinins
- leukotrienes
- thormboxanes
What does histamine cause?
- vasodilation (of small blood vessels)
- ↑ capillary permeability
- Constriction of extravascular smooth muscle
- gastric acid secretion (H2-mediated)
- Neurotransmission
* pain, itching, awake, suppress appetite
Histamines Mechanism of Action
act as antagonists (blocks) at the H1 receptor
* causes vasodilation * ↑ capillary permeability * itching * redness
Are Antihistamines effective or ineffective for hypersensitivity reactions / severe allergic reactions?
limited effectiveness (not very effective)
Antihistamines can be both __________.
sedative and CNS stimulating
What is a paradoxical reaction?
a patient experiences the opposite of what you would expect the drug to do
Paradoxical Reaction with Antihistamines
- Dizziness
- Tinnitus
- Incoordination
- Insomnia
- Tremors
- Nervousness
Side Effects of Antihistamines
- CONSTIPATION
- WEIGHT GAIN
- DROWSINESS
- loss of appetite
- nausea & vomiting
- diarrhea
What is a major difference between first generation and second generation antihistamines?
First generation agents are sedating & second generation agents are non-sedating (less sedating)
What are first generation Antihistamine agents are often used for?
anti-nausea and anti-vomiting
First Generation Antihistamine Drugs
Hydroxizine (good for severe itching)
Meclizine
Promethazine
Stimulation of ______ can trigger nausea & vomiting.
chemoreceptor trigger zone (CTZ)
Which antihistamine is good for severe itching?
hydroxyzine
Effects of Hydroxyzine & Meclizine on the body
↑↑ CNS-depressant effects
Effects of Promethazine on the body
- Anti-Acetylcholine (anti-ACh), Anti-Dopamine, & Antihistamine effects
- ↑↑ sedation
Promethazine is mainly used as _______
antiemetic
Second Generation Antihistamine Mechanism of Action
What do second generation antihistamines cause?
H1 antagonist
- Less Sedation … ↓ CNS penetration
Second Generation Antihistamine Drugs
- Cetirizine (Zyrtec) - can be sedating
- Levocetirizine (Xyzal)
- Loratadine (Claritin)
What is unique about second generation antihistamines?
- work peripherally (not in the CNS)
- don’t work well for anti-nausea / anti-vomiting
Characteristics of Parkinson’s Disease
- Limb muscle rigidity
- Resting tremor
- Bradykinesia (slow movement)
- Postural instability
- depression, psychosis, dementia
What is the cause of Parkinson’s Disease?
loss of dopamine releasing neurons in the nigrostriatal pathway
Explain what is meant by inhibiting the inhibitor in Parkinson’s Disease
When dopamine releasing neurons are lost, the ability to turn off GABA neurons is lost.
Therefore, GABA neurons are turned on more often releasing more & more GABA which affects movement (ACTIVE GABA SLOWS MOVEMENT)
What compound in the brain enhances the effects of GABA (slowing of movement)
Acetylcholine
If Parkinson’s Disease is caused by too much activity of the GABA neuron due to the loss of dopamine releasing neurons, what are the main options for treating Parkinson’s Disease?
- drugs that help the brain make more dopamine
- drugs that act like dopamine
- blocking acetylcholine in the brain
What is Levodopa?
dopamine precursor meaning neurons turn it INTO dopamine
Why is Levodopa often given with Carbidopa?
Carbidopa PREVENTS Levodopa from being turned into Dopamine OUTSIDE of the brain. This allows Levodopa to get into the brain before it is synthesized into Dopamine
What is one important fact to remember when giving / for patients who take Levodopa?
It should not be taken with food to minimize competition with transport pumps which can lead to delayed uptake of the drug
What is the most common side effect associated with Levodopa?
Dyskinesia (occurs in up to 80% of patients)
What is “Wearing Off” in regard to Parkinson’s Disease?
as Parkinson’s progresses (declining dopamine concentrations) each dose of Levodopa lasts for a shorter amount of time
↓ drug concentration = ↑ symptoms
What is “On-Off” in regard to Parkinson’s Disease?
patient is doing well on medication (Levodopa) and suddenly symptoms come back
- NOT related to concentration
What is the difference in “Wearing Off” and “On-Off” in regard to Levodopa and Parkinson’s Disease?
WEARING OFF: as Parkinson’s progresses, the dose of Levodopa lasts for a shorter amount of time
* ↓ drug concentrations = ↑ symptoms
ON-OFF: patient is doing well on Levodopa and suddenly their symptoms come back
* NOT related to drug concentration
Side Effects of Levodopa
- DYSKINESIA (most common)
- Nausea / Vomiting
- Orthostatic Hypotension
- Psychosis
- Sedation
- ↑ risk of Melanoma
- discoloration of sweat & urine
What does Dopamine do in the Central Nervous System (CNS)?
- voluntary movement
- cognition
- motivation
- reward / punishment
- sleep
- inhibition of prolactin (hormone from pituitary)
What does Dopamine do in the Peripheral Nervous System (PNS)?
- Blood Pressure regulation
- Regulation of peristalsis (inhibition)
- Nausea / Vomiting
Dopamine Agonist Drugs
- Pramipexole (Mirapex)
- Ropinirole (ReQuip)
Dopamine Agonists Mechanism of Action
bind to and activate dopamine receptors
Side Effects of Dopamine Agonists
- Hallucinations
- Sleepiness
- Orthostatic Hypotension
- Impulse Control Disorders (ICD)
- Nausea & Vomiting
- Syncope
What Parkinson’s Disease Drug Class causes Impulse Control Disorder (ICD)?
Dopamine Agonists
How do Dopamine Agonists differ from Levodopa?
- Less effective
- Don’t treat movement disorders
- Better tolerated (than Levodopa), less side effects
What occurs when Anticholinergic (antimuscarinic) receptors in the body are blocked?
- dry mouth (Salivation)
- dry eyes (Lacrimation)
- urinary hesitancy (Urination)
- constipation (Defecation)
- Tachycardia
What do Procholinergic drugs do to the body?
- Salivation = ↑ saliva production
- Lacrimation = ↑ tears
- Urination = ↑ frequency
- Defecation = diarrhea
- Bradycardia
What do Anticholinergic (antimuscarinic) drugs do to the body?
- Salivation = dry mouth
- Lacrimation = dry eyes
- Urination = urinary hesitancy
- Defecation = constipation
- TACHYCARDIA
What do anticholinergics (antimuscarinics) to the parasympathetic nervous system?
BLOCK the PNS causing dry mouth, dry eyes, constipation, urinary hesitancy, & tachycardia
What compound activates cholinergic receptors?
acetylcholine
What do anticholinergics (antimuscarinics) block?
histamine AND muscarinic receptors (blocks effects of acetylcholine at muscarinic receptors)
- leads to dry eyes, dry mouth, urinary hesitancy, constipation, & tachycardia *
Anticholinergic Agent Drugs
Benztropine (Cogentin)
Anticholinergic Agent Drugs Mechanism of Action
Block muscarinic receptors in the brain (and entire body)
- block ACh at muscarinic receptors *
Which drug class does NOT work well for Parkinson’s Disease?
Anticholinergic Agents
When are Anticholinergic Drugs used?
to enhance the actions of Levodopa or to enhance the actions of a dopamine receptor agonist
Anticholinergic Drugs are often used in conjunction with what other drug classes?
Levodopa (Dopamine Precursor)
Dopamine Receptor Agonist
Adverse Side Effects of Anticholinergic Drugs
- Dry mouth
- Dry eyes
- Urinary hesitancy
- Constipation
- Tachycardia
- Drowsiness
- Confusion
- Memory Problems
- Delusions
Symptoms of Alzheimer’s Disease
COGNITIVE DYSFUNCTION
* memory loss
* aphasia (speech)
* apraxia (movement)
* disorientation
* loss of executive function
NEUROPSYCHIATRIC SYMPTOMS
* psychotic symptoms
* inappropriate behavior
* depression
Cognitive Dysfunction Symptoms Associated with Alzheimer’s Disease
memory loss
aphasia
apraxia
disorientation
loss of executive funciton
Neuropsychiatric Symptoms Associated with Alzheimer’s Disease
psychotic symptoms
inappropriate behavior
depression
What drug class is the first line of action for patients with mild to moderate Alzheimer’s Disease?
Cholinesterase Inhibitors
Cholinesterase Inhibitors Mechanism of Action
Inhibit Cholinesterase by breaking down Acetylcholine (ACh)
ACh –> Choline + Acetic Acid
What cholinesterase inhibitor is used in the treatment of MILD–MODERATE Alzheimer’s Disease?
Donepezil (ODT - orally disintegrating tablet)
What cholinesterase inhibitor is used in the treatment of MODERATE–SEVERE Alzheimer’s Disease?
Memantine (Namenda)
Memantine Mechanism of Action
Blocks activation of glutamate receptors
Adverse Side Effects of Memantine
- Confusion
- Constipation
- Coughing
- Dizziness
- Hallucinations
- Headache
- Hypertension
What is unique about Memantine?
- long half-life (60-80 hours)
- NMDA Antagonist
- NMDA = specific glutamate receptor
What is important to avoid when using cholinesterase inhibitors?
avoid abrupt discontinuation
- can result in acute impairment in cognition and / or behavioral problems
Blocking cholinesterase does what to acetylcholine levels?
↑ ACh in the brain
What type of drug are cholinesterase inhibitors?
procholinergic (Muscarinic drugs)
cause: * diarrhea * bradycardia * urinary frequency * ↑ salivation * ↑ tears
Side Effects of Cholinesterase Inhibitors
- Bradycardia
- ↑ Salivation
- ↑ Lacrimation (tears)
- Urinary frequency
- Diarrhea
What Drug Classes & Medications in each Class are used to treat Parkinson’s Disease
- Dopamine Precursor (Levodopa)
- Dopamine Agonists (Pramipexole, Ropinirole)
- Anticholinergic Agents (Benztropine)
Which Drug Classes are used in the treatment of Parkinson’s Disease?
- Dopamine Precursor
- Dopamine Agonists (activate dopamine)
- Anticholinergic Agents
Which drugs are used in the treatment of Parkinson’s Disease?
- Levodopa
- Pramipexole
- Ropinirole
- Benztropine
What is asynchronous dosing?
uneven interval of time between dosing; doses are crammed together and then there is a window with no drug in your body
Give an example of asynchronous dosing BID.
Take one dose with breakfast, the next dose at lunch, & then nothing until breakfast the next day
Organic Nitrates Mechanism of Action
donate nitric oxide (NO) to blood vessels making it a STRONG VASODILATOR
Organic Nitrate Therapeutic Use
ANGINA
- also used for HTN & heart failure
What is Tachyphylaxis?
rapid development of drug resistance
Risks & Drug Interactions associated with Organic Nitrates
RISKS: tachyphylaxis (rapid development of drug resistance) – must have 8 hours per day drug-free
DRUG INTERACTIONS
* hypotensives, PDE5 inhibitors (Treat ED)
Adverse Side Effects of Organic Nitrates
- Headache
- Orthostatic hypotension
- Reflex tachycardia (HR ↑ due to ↓ in BP)
What is reflex tachycardia?
Increase in heart rate due to a drop in blood pressure