dopaminergics and muscle relaxants Flashcards
carbidopa-levodopa (sinemet)
pharmacodynamics
parkinsons disease
levodopa circulates in the plasma to the blood-brain barrier where it crosses to be converted by enzymes to dopamine.
And carbidopa inhibits the peripheral plasma breakdown of levodopa, thereby increasing the availability of levodopa at the blood-brain barrier.
carbidopa-levodopa (sinemet)
caution and contraindications
avoid in narrow angle glaucoma, major psych dx, malignant melanoma cardiovascular disease, elderly patients
carbidopa-levodopa (sinemet) patient education
take without food
carbidopa-levodopa (sinemet) ADRs
orthostatic hypotension, somnolence, dizziness, headache, insomnia, abnormal dreams can occur, dyskinesia,
Rare: neuroleptic malignant syndrome and peripheral neuropathy.
dopaminergic
carbidopa-levodopa (sinemet)
muscle relaxant
cyclobenxaprine (flexeril), baclofen (lioresal), metaxalone (skelaxin) tizanidine (zanaflex) methocarbamol (robaxin)
baclofen indications and pharmacodynamics
severe muscle spasms, MS, ALS, spactisity
which inhibits the transmission of both monosynaptic and polysynaptic reflexes at the spinal cord level, possibly by hyperpolarization of primary afferent fiber terminals, which results in the relief of muscle spasticity
baclofen caution and contraindications
renal impairment, elderly (beers list(), seizure disorder, avoid in preganncy, caution in lactation
baclofen ADRs
drowsiness, confusion, headache, nausea, vomiting, hypotension, and seizures.
cyclobenxaprine (flexeril)
acts on monosynaptic and polysynaptic spinal reflexes, inhibiting the monosynaptic reflex affects the messages that are producing and maintaining the skeletal muscle spasms.
cyclobenxaprine (flexeril) ADRs
They can cause dry mouth, drowsiness, constipation, hallucinations, blurred vision. And there is a risk for serotonin syndrome.
cyclobenxaprine (flexeril) caution and contraindications
hyperthyroidism,
heart failure,
arrhythmias, heart blocker conductions or disturbances,
acute recovery phase of having an MI.
patients with urinary retention,
angle-closure glaucoma, or increased ocular pressure; caution in hepatic impairment.
approved in peds > 12 y/o.
limited data in preganacy and lactation
med not to be used longer than 3 weeks
Tizanidine pharmacodynamics
which is a centrally acting alpha-2 adrenergic agonist, which we’re actually going to be talking about soon in this lecture, that reduces muscle spasticity by presynaptic inhibition of motor neurons
tizanidine ADRs
dry mouth, weakness, fatigue, constipation, hypotension, bradycardia.
rare: anaphylaxis and angioedema
tizanidine caution and contrainidcations
hepatic impairement, caution in renal impairement, caution in elderly, avoid in pregancy and lactation, peds limited data.
tizanidine patient education
do not take with alcohol
can cause rebound tachycardia if stopped.
A 45-year-old patient is suffering from back pain due to severe muscle spasms. A centrally-acting muscle relaxant, tizanidine (Zanaflex), is prescribed. By which mechanism of action does tizanidine act?
Tizanidine (Zanaflex) binds to central alpha2 adrenergic receptors, which increases the presynaptic motor neuron inhibition and reducing spasticity.
treatment of choice for parkinsons
carbidopa-levadopa, levodopa, amantadine (symmetrel), bromocriptine (parlodel). ropinirole (requip), pramipexole (mirapex),
ADRs of dopaminergics
n/v, hallucinations, dizziness
monitoring of dopiminergics
hepatic panels d/t risk for hepatocellular injury
education of dopiminergics
avoid abrupt d/c, avoid antacids
drug interactions with dopiminergics
antacids
who must you avoid giving muscle relaxant to?
pregnant women. it can cause uterus to relax and cause miscarriage
muscle relaxants drug interactions
CNS depressants and sedation
