2. MYSTENIA GRAVIS
• Chronic muscular disease caused by a defec
in neuromuscular transmission characterize
by gradual destruction of Ach receptors.
• characterized by fatigue and severe
weakness of skeletal muscles
2
5. DRUGS FOR MYASTHENIA GRAVIS
1. NEOSTIGMINE
ACTION:
– Inhibit destruction of Ach facilitating transmission
of impulse across myoneural junction
PHARMACOKINETICS:
• Poorly absorbed orally
• Can cross blood-brain barrier affect CNS
• Duration of action 2-4hrs
5
6. DRUGS FOR MYASTHENIA GRAVIS
1. NEOSTIGMINE
CONTRAINDICATION:
• Obstruction of GI tract, urinary tract
• Peptic ulcer disease
• Asthma
• Coronary insufficiency
• Hyperthyroidism
6
7. DRUGS FOR MYASTHENIA GRAVIS
1. NEOSTIGMINE
ADVERSE EFFECTS:
• EXCESSIVE MUSCARINIC STIMULATION
– Excessive salivation
– Increased gastric secretion
– Increased tone and motility of GI
– Urinary urgency
– Bradycardia
– Sweating
7
8. DRUGS FOR MYASTHENIA GRAVIS
1. NEOSTIGMINE
ADVERSE EFFECTS:
• NEUROMUSCULAR BLOCKADE
– Accumulation of Ach in amount sufficient to produce
depolarizing neuromuscular blockade
– Results in paralysis of respiratory muscles
8
9. DRUGS FOR MYASTHENIA GRAVIS
2. PYRIDOSTIGMINE (Mestinon)
• Inhibit destruction of Ach
• Has longer duration than neostigmine
• * adverse reaction: decreased HR, diarrhea
and hypotension
9
10. DRUGS FOR MYASTHENIA GRAVIS
3. EDROPHONIUM (Tensilon)
• A drug with very short duration of action (10-20 min)
• PRIMARILY USED AS A DIAGNOSTIC AGENT to differentiate
myasthenic crisis from cholinergic crisis
• If the drug alleviates symptoms = MYASTHENIC CRISIS
• If the drug intensifies symptoms = CHOLINERGIC CRISIS
10
12. ALZHEIMERS DISEASE
• Progressive disorder involving neuronal
degeneration in the cortex leading to loss of
memory and inability to perform activities of
daily living
12
13. DRUGS FOR ALZHEIMERS DISEASE
1. COGNEX
• 1st cholinesterase inhibitor approved for
Alzheimer’s disease
• Administered orally
• Food decreases absorption
• Blood levels peak in 2 hrs, with short half-
life of 3hrs, must be administered 4x a day
• Cause liver damage with high dose
13
14. DRUGS FOR ALZHEIMERS DISEASE
2. ARICEPT
• Current agent of choice
• Well-absorbed orally
• Eliminated mainly in urine and partly in
bile
• Has longer plasma half-life of 6hrs
• Administered 1x a day
14
18. SEIZURES
• Sudden and rapid firing of electrical
impulse from neuron located in brain
• Generalized seizures begin in 1 area and
spread throughout the different areas of
the brain
• Partial seizures involve only 1 area of
the brain and remain localized.
18
19. DRUGS FOR SEIZURES
1. HYDANTOINS
• Stabilize nerve membranes and limit spread of
excitability from the initiating focus
Drugs:
1. phenytoin (Dilantin) = prototype drug
2. ethotoin
3. fosphenytoin
4. mephenytoin
19
20. DRUGS FOR SEIZURES
1. HYDANTOINS
INDICATION:
– Tonic-clonic seizures
PHARMACOKINETICS:
• Slowly absorbed in small intestine
• Excreted in urine
• Highly protein bound, thus, decrease in serum protein
or albumin can increase free phenytoin serum level
• Half-life is 22 hrs
20
21. DRUGS FOR SEIZURES
1. HYDANTOINS
CONTRAINDICATIONS:
• Psyche conditions
• Bradycardia
• Hepatic failure
CAUTION:
• Pregnancy – can cause birth defects and
bleeding tendencies
21
22. DRUGS FOR SEIZURES
1. HYDANTOINS
ADVERSE EFFECTS:
1. GINGIVAL HYPERPLASIA
2. Neurologic and psyche SE like slurred speech,
confusion, depression and thrombocytopenia
3. Hyperglycemia = effect of drug inhibiting release
of insulin
Less severe AE:
1. Alopecia
2. Hirsutism
3. Nystagmus
4. N&V
22
23. DRUGS FOR SEIZURES
1. HYDANTOINS
SPECIAL NURSING CONSIDERATIONS:
1. Administer IV infusion of phenytoin directly
into a large vein.
– Maybe diluted in NSS; dextrose solution should be
avoided-cause drug precipitation
2. Do not administer continuously
– 50 mg can be administered in a period of
1min for adult and 25mg in elderly
23
24. DRUGS FOR SEIZURES
1. HYDANTOINS
SPECIAL NURSING CONSIDERATIONS:
3. Monitor local irritation at injection site
4. Monitor drug levels as ordered; therapeutic
level 10-20mcg/ml
5. Enteral feeding interfere oral absorption. Stop
feeding for 2 hrs before and after
administration
24
25. DRUGS FOR SEIZURES
2. SUCCINIMIDES
ACTION:
– Suppress the abnormal electrical activity in
the brain associated in petit mal or absence
seizure
INDICATION:
– Control of absence seizures
25
26. DRUGS FOR SEIZURES
2. SUCCINIMIDES
– Absorbed in GI tract
– Peak levels of 1-7hrs
– Metabolized in liver
– Excreted in urine
– Able to cross placenta and enter breast milk
26
27. DRUGS FOR SEIZURES
2. SUCCINIMIDES
CONTRAINDICATIONS:
– Renal/hepatic disease
– Pregnancy and lactation
– Intermittent porphyria
27
28. DRUGS FOR SEIZURES
2. SUCCINIMIDES
ADVERSE EFFECTS:
• Depressing effects in CNS:
– Depression, drowsiness, ataxia, insomnia, HA and
blurred vision
• Bone marrow suppression and dermatologic
reaction:
– Pruritus, urticaria, alopecia and Steven Johnson’s
syndrome
28
29. DRUGS FOR SEIZURES
2. SUCCINIMIDES
GENERAL NURSING CONSIDERATIONS:
1. Discontinue at any sign of hypersensitivity
reaction, liver dysfunction or severe skin rash
– to prevent potential fatal reaction.
2. Administer with food
– to alleviate GI upset
3. Women of child-bearing age should be referred
for counseling
– may cause serious damage to fetus
29
30. DRUGS FOR SEIZURES
2. SUCCINIMIDES
GENERAL NURSING CONSIDERATIONS:
4. Suggest wearing of MedicAlert bracelet
– to alert emergency workers about the use of the drugs
5. Monitor CBC before and periodically during
therapy
– to detect bone marrow suppression early and provide
appropriate interventions
30
32. DRUGS FOR SEIZURES
3. DRUGS FOR PARTIAL/FOCAL SEIZURES
ACTION:
– Control partial or focal seizures either by
acting on the sodium and calcium channels or
increasing GABA activity
32
33. DRUGS FOR SEIZURES
3. DRUGS FOR PARTIAL/FOCAL SEIZURES
CONTRAINDICATION:
• Bone marrow suppression
• Hepatic dysfunction
• Pregnancy and lactation
• Presence of renal stones
ADVERSE EFFECTS:
• CNS depression: drowsiness, fatigue,
weakness, confusion and HA
33
35. NEUROMUSCULAR ABNORMALITIES
MUSCLE SPASM
• Result of musculoskeletal injury
– Muscle stretches beyond capacity
• Characterized by painful contraction of muscles
• Spasms are felt when sensory impulses travel fro
the spinal cord to the site of injury, passing
the motor nerves to cause muscle contraction
• Blood flow to the muscle is disrupted causing
lactic acid accumulation and pain
35
36. MUSCLE SPASTICITY
• Permanent condition caused by neuronal
damage in the CNS
• Hyperactive stimulation of the muscles
resulting to loss of muscle coordination
• Ex in MULTIPLE SCLEROSIS
– Lesion in CNS interrupts nerve impulse
resulting to progressive muscle weakness
36
38. CENTRALLY-ACTING MUSCLE RELAXANTS
ACTION:
• Interfere with neuromuscular communication
in CNS to cause muscle relaxation
INDICATION:
• Multiple Sclerosis
• Cerebral palsy
• Any trauma in spinal cord
38
39. CENTRALLY-ACTING MUSCLE RELAXANTS
• Rapidly absorbed orally
• Peak 2-3hrs
• Can cross blood brain barrier and crosses the
placenta
CAUTION:
– CNS depression
– Cardiac dysfunction
– Hepatic and renal dysfunction
– Pregnancy and lactation
39
40. CENTRALLY-ACTING MUSCLE RELAXANTS
NURSING CONSIDERATIONS:
• Discontinue if + hypersensitivity or liver
dysfunction.
– If using baclofen, taper the drugs gradually within 1-2
weeks to prevent dev’t of psychoses
• If receiving baclofen using IV pump, instruct
client about the pump and the rationale for the
need to monitor frequently
• Report if client’s respiratory status
deteriorates
40
42. DIRECT-ACTING MUSCLE RELAXANTS
ACTION:
• Relaxes muscles thru direct action on the
skeletal muscle fibers
• Dantrolene prevents muscular contraction
by inhibiting the release of calcium from
the muscle fibers
42
43. DIRECT-ACTING MUSCLE RELAXANTS
INDICATION:
• Tx of upper motor neuron disorders:
MYASTHENIA GRAVIS & CEREBRAL PALSY
• Acute tx of malignant hyperthermia
(complication of general anesthesia=severe
muscle contraction)
43
44. DIRECT-ACTING MUSCLE RELAXANTS
• Only 30% of oral dose is absorbed, reaching
peak plasma concentration in 5 hrs
• Liver metabolizes the drug
• Crosses the placenta and breastmilk
44
46. DIRECT-ACTING MUSCLE RELAXANTS
NURSING CONSIDERATIONS:
1. Assess for lactose intolerance before drug
administration
– Dantrolene capsules contain lactulose
2. Administer with food or milk to avoid GI
distress
3. Advise to wear appropriate protective
clothing sunscreen when exposed to direct
sunlight
46
47. DIRECT-ACTING MUSCLE RELAXANTS
NURSING CONSIDERATIONS:
4. Provide safety precautions in cases of severe
muscle weakness
5. Provide frequent skin care to prevent skin
breakdown
6. Inform client that hepatitis is 1 of the
dangerous adverse effects
– Loss appetite, n&v, yellow skin or eyes and
changes in urine and stool color.
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