Central Nervous System Drugs Flashcards
Indications: Management of manifestations of psychotic disorders; relief of preoperative restlessness; adjunctive treatment of tetanus; acute intermittent porphyria; severe behavioral problems in children; control of hiccups, nausea, and vomiting.
Actions: Blocks postsynaptic dopamine receptors in the brain; depresses those parts of the brain involved in wakefulness and emesis; anticholinergic; antihistaminic; alphaadrenergic blocking.
Pharmacokinetics:
Route Onset Peak Duration
Oral 30–60 min 2–4 h 4–6 h
Intramuscular 10–15 min 15–20 min 4–6 h
T1/2: 2 hours, then 30 hours; metabolized in the liver, excreted
in the urine.
Adverse effects: Drowsiness, insomnia, vertigo, extrapyramidal symptoms, orthostatic hypotension, photophobia, blurred vision, dry mouth, nausea, vomiting, anorexia, urinary retention, photosensitivity.
Chlorpromazine
Indications: Management of severely ill patients with schizophrenia who are unresponsive to standard drugs; reduction of risk of recurrent suicidal behavior in patients with schizophrenia or schizoaffective disorder.
Actions: Blocks dopamine and serotonin receptors; depresses
the RAS; anticholinergic; antihistaminic; alpha-adrenergic
blocking.
Pharmacokinetics:
Route Onset Peak Duration
Oral Varies 1–6 h Weeks
T1/2: 4–12 hours; metabolized in the liver, excreted in the urine
and feces.
Adverse effects: Drowsiness, sedation, seizures, dizziness,
syncope, headache, tachycardia, nausea, vomiting, fever, neuroleptic malignant syndrome.
Clozapine
Indications: use as a temporary measure in hospitalized patients with acute respiratory insufficiency superimposed on chronic obstructive pulmonary disease.
Actions: Doxapram produces respiratory stimulation mediated through the peripheral carotid chemoreceptors. It is thought to stimulate the carotid body by inhibiting certain potassium channels.
Adverse effects: flushing, sweating, headache, dizziness,
nausea,diarrhea, and enlarged pupils.
Doxapram
Indications: Narcolepsy and attention-deficit disorder.
Actions: Mild cortical stimulant with CNS actions similar to those of amphetamines.
Pharmacokinetics:
Route Onset Peak Duration
Oral Varies 1–3 h 4–6 h
T1/2: 1–3 hours; metabolized in the liver; excreted in the urine.
Used: Given to increase a child’s attention span and cognitive
Adverse effects: Nervousness, insomnia, increased or decreased pulse rate and blood pressure, tachycardia, loss of appetite, nausea, abdominal pain.
Methylphenidate
Indications: Control of tonic-clonic and psychomotor seizures;
prevention of seizures during neurosurgery; control of status
epilepticus.
Actions: Stabilizes neuronal membranes and prevents hyper-
excitability caused by excessive stimulation; limits the spread of seizure activity from an active focus; has cardiac antiar rhythmic effects similar to those of lidocaine.
Pharmacokinetics:
Route Onset Peak Duration
Oral Slow 2–12 h 6–12 h
IV 1–2 h Rapid 12–24 h
T1/2: 6 to 24 hours; metabolized in the liver, excreted in the
urine.
Adverse effects: Nystagmus, ataxia, dysarthria, slurred speech,
mental confusion, dizziness, fatigue, tremor, headache, dermatitis, Stevens-Johnson syndrome, nausea, gingival hyperplasia, liver damage, hematopoietic complications, sometimes fatal.
Phenytoin
Indications: Long-term treatment of generalized tonic-clonic
and cortical focal seizures; emergency control of certain acute
convulsive episodes (status epilepticus, tetanus, eclampsia,
meningitis); anticonvulsant treatment of generalized tonic–
clonic seizures and focal seizures (parenteral).
Actions: General CNS depressant; inhibits impulse conduction
in the ascending RAS; depresses the cerebral cortex; alters
cerebellar function; depresses motor output, and can produce
excitation, sedation, hypnosis, anesthesia, and deep coma.
Pharmacokinetics:
Route Onset Duration
Oral 30–60 min 10–16 h IM, SC 10–30 min 4–6 h IV 5 min 4–6 h
T1/2: 79 hours; metabolized in the liver, excreted in the urine.
Adverse effects: Somnolence, insomnia, vertigo, nightmares, lethargy, nervousness, hallucinations, insomnia, anxiety, dizziness, bradycardia, hypotension, syncope, nausea, vomiting, constipation, diarrhea, hypoventilation, respiratory depression, tissue necrosis at the injection site, withdrawal syndrome.
Phenobarbital
Indications: Management of anxiety disorders; acute alcohol
withdrawal; muscle relaxant; treatment of tetanus; adjunct in
status epilepticus and severe recurrent convulsive seizures;
preoperative relief of anxiety and tension; management of
epilepsy in patients who require intermittent use to control
bouts of increased seizure activity
.
Actions: Acts in the limbic system and reticular formation;
potentiates the effects of GABA; has little effect on cortical
function.
Pharmacokinetics:
Route Onset Peak Duration
Oral 30–60 min 1–2 h 3 h
IM 15–30 min 30–45 min 3 h
IV 1–5 min 30 min 15–60 min
Rectal Rapid 1.5 h 3 h
T1/2: 20 to 80 hours; metabolized in the liver, excreted in the
urine.
Adverse effects: Drowsiness, sedation, depression, lethargy,
apathy, fatigue, disorientation, bradycardia, tachycardia,
paradoxical excitatory reactions, constipation, diarrhea, incontinence, urinary retention, drug dependence with withdrawal syndrome.
Diazepam
Indications: Control of absence seizures.
Actions: May act in inhibitory neuronal systems; suppresses
the electroencephalographic pattern associated with the absence seizures; reduce the frequency of attacks.
Pharmacokinetics:
Route Peak
Oral 3–7 h
T1/2: 30 hours (children), 60 hours (adults); metabolized in the liver, excreted in the urine and bile.
Adverse effects: Drowsiness, ataxia, dizziness, irritability,
nervousness, headache, blurred vision, pruritus, Stevens–
Johnson syndrome, nausea, vomiting, epigastric pain, anorexia,
diarrhea, and pancytopenia.
Ethosuximide
Indications: Treatment of seizure disorders, including partial
seizures with complex patterns; tonic-clonic seizures; mixed
seizures; trigeminal neuralgia.
Actions: Inhibits polysynaptic responses and blocks post-tetanic potentiations; mechanism of action is not understood; related to tricyclic antidepressants.
Pharmacokinetics:
Route Onset Peak
Oral Slow 4–5 h
Extended-release oral Slow 3–12 h
T1/2: 25 to 65 hours, then 12 to17 hours; metabolized in the
liver, excreted in the urine and feces.
Adverse effects: Drowsiness, ataxia, dizziness, nausea, vomiting, CV complications, hepatitis, hematological disorders, Stevens–Johnson syndrome.
Carbamazepine
Indications: Treatment of parkinsonism and Parkinson’s dis-
ease.
Actions: The precursor of dopamine, which is deficient in parkinsonism; crosses the blood-brain barrier, where it is converted to dopamine and acts as a replacement neurotransmitter; it is effective for 2 to 5 years in relieving the symptoms of Parkinson’s disease.
Pharmacokinetics:
Route Onset Peak Duration
Oral Varies 0.5–2 h 5 h
T1/2: 1 to 3 hours; metabolized in the liver, excreted in the
urine.
Adverse effects: Adventitious movements, ataxia, increased hand tremor, dizziness, numbness, weakness, agitation, anxiety, anorexia, nausea, dry mouth, dysphagia, urinary retention, flushing, and cardiac irregularities.
Levodopa
Indications: Adjunctive therapy for Parkinson’s disease; relief
of symptoms of extrapyramidal disorders (parkinsonism) that
accompany phenothiazine therapy.
Actions: Acts as an anticholinergic, principally in the CNS, returning balance to the basal ganglia and reducing the severity of rigidity, akinesia, and tremors; peripheral anticholinergic effects help to reduce drooling and other secondary effects of parkinsonism.
Pharmacokinetics:
Route Onset Peak Duration
Oral 1 h 1–1.5 h 6–12 h
IM 15 min Unknown Unknown
T1/2: 18.4 to 24.3 hours; metabolized in the liver.
Adverse effects: Disorientation, confusion, memory loss,
nervousness, light-headedness, dizziness, depression, blurred vision, mydriasis, dry mouth, constipation, urinary retention,
urinary hesitation, flushing, and decreased sweating.
Biperiden
Indications: used to treat excessive sleepiness caused by sleep apnea, narcolepsy, or shift work sleep disorder.
Actions: It has little to no in vivo affinity for the serotonin (5HT) or norepinephrine (NE) transporters. However, elevated concentrations of NE and 5HT in the prefrontal cortex and hypothalamus have been observed following modafinil administration, possibly as an indirect effect of increased extracellular dopamine. Modafinil exists as a racemic mixture of S- and R-enantiomers. The R-enantiomer is thought to be the source of modafinil’s psychotropic properties and is marketed independently as armodafinil
Modafinil
Indications: Alleviation of signs and symptoms of spasticity;
may be of use in spinal cord injuries or spinal cord diseases.
Actions: Gamma-aminobutyric acid (GABA) analogue; exact
mechanism of action is not understood; inhibits monosynaptic
and polysynaptic spinal reflexes; CNS depressant.
Pharmacokinetics:
Route Onset Peak Duration
Oral 1 h 2 h 4–8 h
Intrathecal 30–60 min 4 h 4–8 h
T1/2: 3 to 4 hours; not metabolized; excreted in the urine.
Adverse effects: Transient drowsiness, dizziness, weakness,
fatigue, constipation, headache, insomnia, hypotension, nausea,
urinary frequency.
Baclofen
Indications: Control of clinical spasticity resulting from upper
motor neuron disorders; preoperatively to prevent or attenuate the development of malignant hyperthermia in susceptible patients; IV for management of fulminant malignant hyperthermia.
Actions: Interferes with the release of calcium from the
sarcoplasmic reticulum within skeletal muscles, preventing
muscle contraction; does not interfere with neuromuscular
transmission.
Pharmacokinetics:
Route Onset Peak Duration
Oral Slow 4–6 h 8–10 h
IV Rapid 5 h 6–8 h
T1/2: 9 hours (oral), 4 to 8 hours (IV); excreted in the urine.
Adverse effects: Drowsiness, dizziness, weakness, fatigue,
diarrhea, hepatitis, myalgia, tachycardia, transient blood
pressure changes, rash, urinary frequency.
Dantrolene
Indications: Relief of moderate to severe acute or chronic pain; preoperative medication; component of combination
therapy for severe chronic pain; intraspinal to reduce intractable pain.
Actions: Acts as an agonist at specific opioid receptors in the
CNS to produce analgesia, euphoria, and sedation.
Pharmacokinetics:
Route Onset Peak Duration
Oral Varies 60 min 5–7 h
PR Rapid 20–60 min 5–7 h
SQ Rapid 50–90 min 5–7 h
IM Rapid 30–60 min 5–6 h
IV Immediate 20 min 5–6 h
T1/2: 1.5 to 2 hours; metabolized in the liver, excreted in the urine and bile.
Adverse effects: Light-headedness, dizziness, sedation, nausea, vomiting, dry mouth, constipation, ureteral spasm, respiratory depression, apnea, circulatory depression, respiratory arrest, shock, cardiac arrest.
Morphine
