Anti-spasticity Agents Flashcards
What are the names of some common centrally-acting anti-spasticity agents?
Baclofen (Lioresal)
Diazepam (Valium)
Tizanidine (Zanaflex)
What are the names of some common peripherally-acting anti-spasticity agents?
Dantrolene (Dantrium)
What is a positive of centrally-acting anti-spasticity agents?
No ceiling effects
Baclofen (Lioresal) - site of action
GABA-b receptors
Baclofen (Lioresal) - side effects:
Sedation Ataxia Hypotension Slurred speech Respiratory depression Hallucinations
Baclofen (Lioresal) - drug interactions:
Drugs that also cause sedation Methadone Mirtazapine Zolpidem Azelastine Buprenorphine
Baclofen (Lioresal) - clinical considerations:
Effectiveness limited by systemic SEs
Limited ability to cross the BBB (where spasticity comes from)
May lower the seizure threshold
Withdrawal sx
What is one way to combat Baclofen’s limited ability to cross the BBB?
It is also available intrathecally or via a pump (usually placed between T12/L1)
Indications for intrathecal Baclofen (Lioresal):
Severe spasticity unresponsive to oral agents
Intolerable SEs at effective oral doses (systemic reactions)
What is a positive of Baclofen (Lioresal)
Fewer systemic SEs because it is injected directly into the SC
When can intrathecal Baclofen (Lioresal) be prescribed?
After an initial screening hospital admission trial of 1-3 days
Is there a black box warning associated with intrathecal Baclofen (Lioresal)?
YES - abrupt discontinuation may lead to organ failure or death
Intrathecal Baclofen (Lioresal) - complications:
Infection Dislodged pump Blocked or twisted catheter Pump failure OD
Diazepam (Valium) - site of action:
Brainstem reticular formation
Spinal polysynaptic pathways
Diazepam (Valium) - side effects:
Sedation Decreased gait speed Muscle weakness Hypotension Ataxia Constipation
Diazepam (Valium) - half-life:
20-80 hours
How is the half-life of Diazepam (Valium) determined?
Age
Diazepam (Valium) - side effects:
Antifungal agents Azelastine CCBs Azithromycin Methadone
Diazepam (Valium) - clinical considerations:
Class IV controlled substance
Long half-life - not recommended in elderly (Beers)
Avoid alcohol - potentiates CNS depression
What are common anticholinergic effects caused by antihistamines?
Flushing
Dry mouth
Difficulty urinating
Cognitive effects
Tizanidine (Zanaflex) - site of action:
Alpha-2 adrenergic receptors
Tizanidine (Zanaflex) - side effects:
Sedation Dizziness Dry mouth Hypotension Hepatotoxicity
Tizanidine (Zanaflex) - clinical considerations:
Avoid in patients with liver disease
Withdrawal sx may occur if therapy stopped suddenly
Dantrolene (Dantrium) - site of action:
Skeletal muscle Ca++ stores
Dantrolene (Dantrium) - use:
For spasticity that limits rehab progression
Dantrolene (Dantrium) - side effects:
Fatigue Dizziness Weakness Malaise Diarrhea Hepatotoxicity
Dantrolene (Dantrium) - contraindications:
Patients who require spasticity to remain upright or balanced (SCI)
Liver disease
Dantrolene (Dantrium) - interactions:
Methadone
Azelastine
Mirtiazapine
Zolpidem
Dantrolene (Dantrium) - clinical considerations:
Fewer cognitive side effects
Alcohol enhances sedation
For what is botulinum toxin (Botox) approved?
Treatment of UE spasticity
For who is Botulinum toxin (Botox) indicated?
Patients with painful spasticity that limits skin hygiene and daily functioning (CP)
Effects of botulinum toxin (Botox):
Decreased muscle tone
Increased ROM
What is the black box warning associated with Botulinum toxin (Botox)?
Injected toxins may spread to distal sites and cause sx of botulism (can be fatal)
Botulinum toxin (Botox) - side effects:
Fatigue Nausea Bronchitis Pain @ injection site Weakness
