Question

18. Explain the basic differences, in terms of sites and mechanisms of action, among centrally acting muscle relaxants, baclofen, diazepam, and dantrolene. State how these different mechanisms and site of action relate to the drugs' clinical uses. 19. Mr. Urlacher has been diagnosed as having MS. As part of his treatment, he is given baclofen (Lioresal) for muscle spasticity. He is your assigned patient fir the morning. Your clinical instructor has informed you that Mr. Urlacher has many questions about the use of baclofen for the treatment of spasticity. How will you best answer the following questions? "How does baclofen work?" "What are the side effects of this drug?" "What precautions will I need to be aware of with this drug?" "If I stop taking it, what can happen?" 20. Discuss at least 4 medications that are commonly prescribed to patients who have muscle spasticity (example, for MS patients). Name 4 specific medications and discuss the following of each: How do they work? What are the contraindications of the medications? What are the side effects?

Answer 1

18. Basic difference in terms of site and mechanism of action :-

Diazepam - it is a benzodiazepine, so it increases the central inhibitory effects of GABA. Specifically, the drug increases muscle relaxation through potentiating GABAergic effects on alpha motor neurons in the spinal

Baclofen -  Baclofen is an agonist of GABA, and binds preferentially to GABA(B) receptors within the spinal cord at specific synapses. By binding to GABA(B) it then increases GABAergic inhibitory effects, successfully inhibiitng alpha motor neurons in the spinal cord.

Dantrolene - It is a direct acting skeletal muscle relaxant that binds to the ryanodine receptor reducing it's open state and blocking calcium release from the sarcoplasmic reticulum without altering calcium reuptake.

19. Baclofen works by binding to the GABA receptor at the synapses and causes inhibition of alpha motor neurones and hence reduces spasticity.

Side effects of medication are - May result in fever, mental status changes, exaggerated rebound spasticity, and muscle rigidity. Caution patient to avoid abrupt withdrawal of this medication because it may precipitate an acute withdrawal reaction (hallucinations, increased spasticity, seizures, mental changes, restlessness).

20. Four drugs for muscle spasticity are :-

1. Diazepam - it is a benzodiazepine, so it increases the central inhibitory effects of GABA. Specifically, the drug increases muscle relaxation through potentiating GABAergic effects on alpha motor neurons in the spinal

#. Adverse effects of diazepam :-

1. sedation and general reduction in psychomotor ability

2. May develop tolerance/physical dependence

3. Sudden withdrawal may induce seizures, anxiety, agitation, tachycardia, or death

2. Baclofen :-

Baclofen is an agonist of GABA, and binds preferentially to GABA(B) receptors within the spinal cord at specific synapses. By binding to GABA(B) it then increases GABAergic inhibitory effects, successfully inhibiitng alpha motor neurons in the spinal cord.

Adverse effects - May result in fever, mental status changes, exaggerated rebound spasticity, and muscle rigidity.

3. Dantrolene :-

- It is a direct acting skeletal muscle relaxant that binds to the ryanodine receptor reducing it's open state and blocking calcium release from the sarcoplasmic reticulum without altering calcium reuptake.

#. Adverse effects :-

Malignant hyperthermia

Potentially fatal condition caused by succinylcholine and general anesthetics

*Hepatic Toxicity** Dose-related liver damage is the most serious adverse effect.

Because of these, should be administered in the lowed effective dosage and for the shortest time necc

4. Trileptal oxcarbazepine :-

Voltage-sensitive sodium channels in neuronal membranes blocked, hyperexcitable neurons stabilized, and seizures suppressed

Adverse effects: Dizziness, drowsiness, double vision, nystagmus, headache, nausea, vomiting, and ataxia. This medicine can cause dry mouth from too little production of saliva.

Stevens-Johnson syndrome SNS

Toxic epidermal necrolysis TEN