Pharmacology for neuromuscular Flashcards
Neostigmine (Prostigmin) class
Cholinesterase inhibitor
Neostigmine (Prostigmin) MOA
Prevents degradation of acetylcholine by cholinesterase
Increases the amount of acetylcholine available to active receptors, thus increasing muscle strength
Improves impulse transmission at the neuromuscular junctions throughout the body
What is acetylcholinesterase?
Acetylcholinesterase is an enzyme that normally breaks down acetylcholine → Neostigmine binds to cholinesterase, taking it up the medication is broken down instead of acetylcholine
Neostigmine (Prostigmin) description
Therapeutic doses increase the force of muscle contraction. At toxic levels, the medication does the opposite and reduces the force of muscle contraction → cholinergic crises
Parasympathomimetic → acetylcholine is the primary neurotransmitter of the parasympathetic nervous system
Indications for neostigmine (Prostigmin)
Used as treatment for Myasthenia Gravis, reverses muscle relaxants
neostigmine (Prostigmin) therapeutic effect
Improved muscle strength
Additional info for neostigmine (Prostigmin)
Administered IV, IM, and Subcutaneous injection (poorly absorbed in the GI tract)
Does not cure Myasthenia Gravis but provides symptom relief
Lifelong use
Adverse effects of neostigmine (Prostigmin)
Excess acetylcholine → excessive salivation, increased gastric secretions, increased tone/ motility of GI tract, urinary urgency, bradycardia, and sweating, bronchial constriction
Toxic doses can cause accumulation of acetylcholine that leads to paralysis of respiratory muscles and worsened muscle weakness
Cholinergic Crises
SLUDGE and the Killer Bs:
S: salivation
L: lacrimation
U: urination
D: diaphoresis/ diarrhea
G: gastrointestinal cramping
E: emesis
B: bradycardia
B: bronchospasm
B: bronchorrhea
Contraindications and precautions for neostigmine (Prostigmin)
Hypersensitivity
Bowel obstruction
Bladder obstruction
Cardiac issues → bradycardia, arrhythmias
Asthma
Nursing considerations and assessment for neostigmine (Prostigmin)
Monitor patient for improvement → increased ability to swallow and open eyelids
Nursing considerations and assessment for neostigmine (Prostigmin)
Monitor patient for improvement → increased ability to swallow and open eyelids
Patient may need to adjust dosage based on activity level (situational)
Assess patient for signs of underdosage (difficulty swallowing, ptosis) and overmedicating (excessive salivation, sweating, bradycardia, urinary urgency, increased GI motility, bronchoconstriction)
Monitor for Myasthenic crisis (under medicating) → extreme muscle weakness and
Monitor for cholinergic crisis (over medicating) → extreme muscle weakness and eventual paralysis and respiratory failure
Reversal agent for excessive muscarinic stimulation (cholinergic crisis) is Atropine
Patient should wear a medic alert bracelet
Myasthenic crisis vs cholinergic crisis
The patient with myasthenia gravis is in suspected cholinergic crisis. Which medication do you anticipate the health care provider will order?
Anticholinergic (Atropine)
Levodopa MOA
Crosses the blood brain barrier and converts to dopamine once it reaches the brain → thus restoring a balance between acetylcholine and dopamine
Indications for levodopa
Parkinson’s disease
Therapeutic effect of levodopa
Reduction in symptom severity, improvement in carrying out ADL’s
Does not cure PD or delay disease progression
Additional info of levodopa
Administered orally
Therapeutic response can take several months
Most effective drug for PD
Effectiveness of Levodopa decreases over time (symptoms are usually well controlled in first 2 years of treatment and effectiveness declines)
A small fraction of medication reaches the brain when it is given alone, and for this reason, Levodopa is given in combination
Levodopa/ Carbidopa (Sinemet)
Carbidopa has no therapeutic effects on its own
When levodopa is taken on its own, only a small portion reaches the CNS → this requires high doses that lead to more side effects
Carbidopa delays the process of peripheral drug metabolism, allowing for more levodopa to enter the brain
Adverse effects of levodopa/ carbidopa (Sinemet)
Nausea and vomiting → due to activation of dopamine receptors in the chemoreceptor trigger zone of the medulla
Dyskinesias → can cause movement disorders; tics, head bobbing, grimacing, rapid involuntary jerking, writhing movements, etc
Postural hypotension
Psychosis → visual hallucinations, vivid dreams, paranoia
CNS effects → anxiety, agitation, memory loss, cognitive impairment, issues with impulse control
Other side effects → can darken sweat and urine
Precautions and contraindications of levodopa/ carbidopa (Sinemet)
Hypersensitivity
Nursing considerations of levodopa/ carbidopa (Sinemet)
On/ Off phenomenon
Wearing-off phenomenon
Patients should avoid high protein meals → compete for absorption in gut
Assess for parkinsonian and extrapyramidal symptoms before and during therapy (shuffling gait, bradykinesia, drooling, pill rolling, tremors, twisting motions, masked face, rigidity)
Monitor blood pressure frequently during therapy
Patient should not transfer to a standing position abruptly
pramipexole (Mirapex) classification
Nonergot dopamine receptor agonist
pramipexole (Mirapex) MOA
Stimulates dopamine receptors in the striatum
Therapeutic effect of pramipexole (Mirapex)
Improve ability to carry out ADL’s → improvement in motor symptoms
Does not cure PD or delay progression of disease
Additional info of pramipexole (Mirapex)
Used on its own in early PD
Used in combination with other Parkinson’s drugs in advanced PD
Effects take several weeks to develop
Given orally
Adverse effects of pramipexole (Mirapex)
Associated with activating dopamine receptors → nausea, dizziness, sleepiness, confusion, hallucinations
When taken on its own, patients do not experience dyskinesias (abnormal movements)
When taken in combination with levodopa, the risk of developing orthostatic hypotension, hallucinations, and dyskinesias increases
“Sleep attacks” are overwhelming and irresistible sleepiness that come on without warning → ++ dangerous
Impulse control disorders → compulsive gambling, shopping, binge eating, hypersexuality
Nursing considerations & assessment of pramipexole (Mirapex)
Patients should be warned about potential to develop drowsiness → patients should not take sedating medications or alcohol while on pramipexole and should be asked about existing sleep disorders
Patients recently started on pramipexole should avoid driving or engaging in dangerous activities until they know whether it affects their wakefulness
If patient experiences sleep attacks, the medication should be discontinued
Monitor blood pressure regularly → advise patient to change positions slowly
Selegiline (Deprenyl) classification
MAO-B inhibitor
What is MAO-B?
MAO-B is an enzyme that inactivates dopamine in the striatum
MOA of selegiline (Deprenyl)
Selegiline is a selective inhibitor of MAO-B. When used in combination with Levodopa, it suppresses the destruction of dopamine derived from Levodopa, so can reduce wearing off effect
Indication for selegiline (Deprenyl)
Parkinson’s Disease, depression
Therapeutic effect of selegiline (Deprenyl)
Improvement in motor function
When used in combination with levodopa, can reduce wearing off effect
Additional info for selegiline (Deprenyl)
This drug is often recommended for newly diagnosed PD → considered first-line drugs
May be used alone or in combination with Levodopa
Administered orally
Adverse effects of selegiline (Deprenyl)
Insomnia (should not take after noon time)
Hypertensive crisis → if taken in high doses (increased risk with younger people)
Drug interactions with selegiline (Deprenyl)
In combination with Levodopa, will worsen orthostatic hypotension, dyskinesia, and psychiatric symptoms
Should not be taken with meperidine or selective serotonin reuptake inhibitors (SSRIs)
Nursing considerations and assessment for selegiline (Deprenyl)
Assess gait and motor function to assess effectiveness of treatment and identity dyskinesia side effects of medication
Monitor patient for changes in behaviour and psychiatric symptoms
If used in combination with Levodopa, monitor blood pressure and discuss risk for falls
Anticholinergics MOA
Block action of acetylcholine
Other treatments directly affect dopamine, whereas anticholinergics work on correcting the imbalance by focusing on acetylcholine
Often used in combination with other antiparkinsonian medications
The goal of Parkinson’s Disease pharmacotherapy is:
a. To increase the amount of acetylcholine at the presynaptic neurons
b. To reduce the amount of dopamine available in the substantia nigra
c. To balance cholinergic and dopaminergic activity in the brain
d. To block dopamine receptors in presynaptic and postsynaptic neurons
c. To balance cholinergic and dopaminergic activity in the brain
A patient with Parkinson’s disease who has been positively responding to drug treatment with levodopa/ carbidopa (Sinemet) suddenly develops a relapse of symptoms. What is this called?
Wearing-off (WO) phenomenon is a frequent complication which is defined as a reoccurrence of motor and non-motor symptoms during levodopa free interval, which has a negative impact on the quality of life of patients.
Which statement should the nurse include in the teaching plan for a patient being started on levodopa/ carbidopa (Sinemet) for newly diagnosed Parkinson’s disease?
a. Take the medication on a full stomach
b. Change positions slowly
c. The drug may cause the urine to be very dilute
d. Carbidopa has many adverse effects
b. Change positions slowly
Interferon beta drugs (Betaseron) classification
Immunomodulator
Interferon beta drugs (Betaseron) MOA
Naturally occurring glycoprotein
Inhibits migration of proinflammatory leukocytes across the blood brain barrier (cannot reach neurons of the CNS)
Suppresses t-helper cell activity
Indication for interferon beta drugs (Betaseron)
Multiple sclerosis
Therapeutic effect of interferon beta drugs (Betaseron)
Can decrease the frequency and severity of relapse, reduce the size and number of lesions, and delay progression of disability
Additional info for interferon beta drugs (Betaseron)
Intramuscular or subcutaneous → depends on the specific drug
Adverse effects of interferon beta drugs (Betaseron)
Flu-like symptoms → headache, fever, chills, malaise, muscle aches, and stiffness (this decreases over time and can be minimized by starting on lower doze and gradually increasing, as well as taking tylenol)
Hepatoxicity → can damage liver cells
Myelosuppression → can suppress bone marrow function, decreasing production of all blood cells
Depression and suicidal ideation
Contraindications of interferon beta drugs (Betaseron)
Hypersensitivity
Patients with previous suicide attempts and depression → use cautiously
Patients with liver disease and alcoholism → use cautiously
Drug interactions for interferon beta drugs (Betaseron)
Should not combine with alcohol or other hepatotoxic medications
Should not take with other immunosuppressants
Nursing considerations and assessment for interferon beta drugs (Betaseron)
Assess for MS symptoms during therapy
Monitor liver function tests and CBC (hgb, platelets, WBC) → prior to treatment and at 1, 3, and 6 month
Monitor for signs of depression
Educate patient about likelihood of experiencing flu like symptoms and offer acetaminophen for relief
Educate about the signs of depression, suicidal ideation, and worsening anxiety
Classification of mitoxantrone (Novantrone)
Immunosuppressant
Cytotoxic drug → this means it kills cells in the body
Mitoxantrone (Novantrone) MOA
It binds with DNA and inhibits DNA and RNA synthesis, causing breakage of DNA strands
Like chemotherapy, Mitoxantrone is more lethal to cells that divide fast → hair, skin, GI mucosa, and bone marrow
Suppresses production of immune system cells and decreases immune system cells and decreases immune system destruction of myelin
Indication for mitoxantrone (Novantrone)
Was developed to treat cancer, but can be used for MS
Therapeutic effect of mitoxantrone (Novantrone)
It can delay MS patients going into relapse, delays disability progression, and can decrease lesions
Adverse effects of mitoxantrone (Novantrone)
Myelosuppression → toxic to bone marrow cells causing decreased platelets, white blood cells, and red blood cells. Reduced neutrophils leads to high risk of infection
Cardiotoxicity → affects left ventricular ejection fraction and can cause heart failure. This can occur months to years after treatment has ended
Teratogenic → potential for fetal harm
Hair loss, nausea/ vomiting, and mouth sores → all related to the death of rapidly dividing cells
Contraindications of mitoxantrone (Novantrone)
Hypersensitivity
Use cautiously in patients with cardiac diseases
Use cautiously in patients with active infections
Nursing considerations and assessments for mitoxantrone (Novantrone)
Monitor for bone marrow depression (bleeding and bruising due to decreased platelets, signs of infection due to decreased neutrophils, signs of anemia due to decreased red blood cells)
Monitor for GI symptoms → administer antiemetics prophylactically
Inspect mouth for sores
Assess fluid and electrolytes, intake, output, appetite, nutrition
Patients should have baseline EKG, chest x-ray, and echo to determine ejection fraction and cardiac status prior to starting therapy and during therapy
Assess for signs of heart failure (auscultate lungs for crackles, assess edema, shortness of breath, chest pain)
IV administration → CAREFUL with handling
Monitor patient IV site carefully - infusion to be stopped if patient develops pain, swelling, redness
Baclofen (Lioresel) classification
Skeletal muscle relaxant
Baclofen (Lioresel) MOA
Acts within the spinal cord (CNS) to suppress hyperactive reflexes involved in the regulation of muscle movement
Structural analog of the inhibitory NT GABA (mimics actions of GABA on spinal neurons)
Indication for baclofen (Lioresel)
Used to relieve muscle spasticity with MS and spinal cord injury
Therapeutic effect of baclofen (Lioresel)
Relieve muscle spasticity
Decrease flexor and extensor spasms and suppresses resistance to passive movement
Administration of baclofen (Lioresel)
PO, intrathecal (a pump surgically placed directly into the spinal fluid of the back)
Adverse effects of baclofen (Lioresel)
CNS depressants: drowsiness, dizziness, weakness, and fatigue (improves over time with longterm use)
Withdrawal symptoms from stopping abruptly (hallucinations, seizures, paranoid ideation. Intrathecal route has a higher risk of severe symptoms (fever, muscle rigidity, exaggerated rebound spasticity, multi-organ failure, death))
Nausea and vomiting
Constipation, urinary retention
Orthostatic hypotension
Nursing considerations and assessment for baclofen (Lioresel)
Extreme caution with other CNS depressants (ETOH, antihistamines, opioids, benzodiazepines)
-Overdose or combination with other CNS depressants can cause respiratory depression
Overdose
-Respiratory depression
-NO ANTIDOTE
Monitor for withdrawal symptoms
Intrathecal route
-monitor infusion system closely
Gabapentin (Neurontin) classification
GABA analog (antiseizure agent)
Gabapentin (Neurontin) MOA
Gabapentin is an analog of GABA but does not directly affect GABA receptors. Its precise mechanism of action is unknown, but it may enhance GABA release, thereby increasing GABA-mediated inhibition of neuronal firing
Indications for gabapentin (Neurontin)
Gabapentin also has approval for treating postherpetic neuralgia
Most used for off-label uses, including relief of neuropathic pain (other than postherpetic neuralgia)
Adverse effects of gabapentin (Neurontin)
Gabapentin is very well tolerated
The most common side effects are somnolence, dizziness, ataxia, fatigue, nystagmus, and peripheral edema. These are usually mild to moderate and often diminish with continued drug use
Caution with other CNS depressants
Mood changes, suicidal ideation
Withdrawal symptoms with abrupt discontinuation
Contraindication for gabapentin (Neurontin)
Hypersensitivity
Nursing considerations and assessment for gabapentin (Neurontin)
Monitor for signs of CNS depression
Improvement of neuropathic pain
Monitor for changes in good, depression, suicidal ideation
