Neurologic and Psychiatric Therapeutics



Neurologic and Psychiatric Therapeutics













TABLE 9.1. Seizures—Urgent Management











































Drug Dosage Comment
Thiamine 100 mg IV/IM To avoid Wernicke’s encephalopathy in alcoholics after glucose administration
Dextrose 50% 25–50 ml IV For hypoglycemic seizures
Diazepam 2.5–10 mg IV, repeat after 5–10 min if needed May cause respiratory depression and hypotension
Seizures may recur because duration of efficacy is short
Phenytoin 10–20 mg/kg IV Maximum infusion rate 50 mg/min
Precipitates if injected into glucose-containing solutions
Arrhythmias develop during rapid administration; monitor ECG
Can produce hypotension
Fosphenytoin 10–20 PE/kg IV Fosphenytoin should be prescribed in PE
Fosphenytoin 75 mg = phenytoin 50 mg
Infusion rate should be 100–150 mg PE/min
Continuous monitoring of ECG, BP, and respiration is essential during IV loading
Peak phenytoin levels occur approximately 2 h after the end of the loading infusion
Fosphenytoin should not be administered IM for the treatment of status epilepticus
Phenobarbital 10–20 mg/kg IV Maximum infusion rate 50 mg/min
Respiratory depression and hypotension should be anticipated
Thiopental 25–100 mg IV Hypotension and apnea are expected
5 mg/kg induces general anesthesia, but with a variable response
Neuromuscular blocking agents See Table 2.4 Neuromuscular blocking agents possess no anticonvulsant properties
For intractable seizures or life-threatening acidosis or muscle contractions
Use of these agents can mask seizure activity; therefore, EEG monitoring is required
General anesthesia For intractable seizures or life-threatening acidosis or muscle contractions
ECG, electrocardiogram; EEG, electroencephalogram; IV, intravenous; IM, intramuscular; PE, phenytoin sodium equivalent; BP, blood pressure










TABLE 9.2. Seizures—Maintenance Therapy


























































Drug Daily Dosage Optimal Blood Level (μg/ml) Comment
Carbamazepine 5–25 mg/kg PO divided tid-qid 4–8 Metabolized to active metabolite
Side effects: nystagmus, dysarthria, diplopia, ataxia, drowsiness, nausea, blood dyscrasias, hepatotoxicity
Fosphenytoin Maintenance dose: 4–6 mg/kg PE total daily dose
IV/IM divided doses q8h
Temporary substitution for oral Dilantin: same as daily oral Dilantin dose in mg		 10–20 (measured as phenytoin)
Free level 1–2		 Fosphenytoin 75 mg = phenytoin 50 mg
Maximum infusion rate 150 mg PE/min
IV infusion requires continuous ECG, BP, and respiratory monitoring
Administer fosphenytoin substitution doses at the same frequency as oral Dilantin
Side effects: tingling, paresthesias after IV administration; other side effects similar to phenytoin
Gabapentin 900 mg PO divided tid — Side effects: fatigue, somnolence, dizziness, ataxia
Lamotrigine 25 mg PO every other day if on valproic acid + enzyme inducer; 50 mg/d if not on valproic acid, but on enzyme inducer — Side effects: rash, abnormal thinking, dizziness, ataxia, nervousness, somnolence, diplopia, nausea, vomiting, weight gain
Phenobarbital 2–5 mg/kg PO/IV qd 10–40 Maximum infusion rate 50 mg/min
Side effects: drowsiness, nystagmus, ataxia, skin rash, learning difficulties
Phenytoin 4–8 mg/kg PO/IV qd Total level:10–20
Free level 1–2		 Maximum infusion rate 50 mg/min
Side effects: nystagmus, ataxia, dyskinesias, sedation, gingival hyperplasia, hirsutism, blood dyscrasias, rashes, systemic lupus erythematosus, peripheral neuropathy
Primidone 5–20 mg/kg PO divided tid Primidone: 5–15
Phenobarbital: 15–40		 Metabolized to phenobarbital, which contributes to pharmacologic activity
Side effects: sedation, nystagmus, ataxia, vertigo, nausea, skin rashes, megaloblastic anemia
Topiramate Goal of 200 mg PO bid
Starting dose 50 mg PO bid		 — Adequate fluid intake should be maintained to minimize the risk of kidney stone formation
Side effects: psychomotor slowing, difficulty in concentrating, speech and language problems, somnolence and fatigue, kidney stone formation
Valproic acid 10–60 mg/kg PO divided tid 50–100 Side effects: nausea, vomiting, diarrhea, drowsiness, alopecia, weight gain, hepatotoxicity, thrombocytopenia, tremor
Valproate sodium injection 10–60 mg/kg IV divided tid-qid
IV dose equals the oral dose when used as a temporary substitute for oral therapy		 IV product is intended for temporary substitution of oral valproate in same daily dose and dosing interval
IV dose should be infused as a 60 min infusion, but not faster than 20 mg/min
BP, blood pressure; ECG, electrocardiogram; IM, intramuscular; IV, intravenous; PE, phenytoin sodium equivalent; PO, by mouth









TABLE 9.3. Increased Intracranial Pressure











































Agent Dosage Comment
Adjunctive therapy Airway and hemodynamic management may be indicated
Neurosurgical consultation
Mannitol 0.25–1.0 g/kg IV, then 0.25–0.5 g/kg IV q4h As needed to maintain ICP without exceeding serum osmolality of 320–400 mOsm
Adverse effects: transient immediate hypervolemia followed by diuresis and hypovolemia; hyperosmolar state; possible rebound increase in ICP after termination, particularly if mannitol is retained by abnormal tissue; exacerbation of intracranial bleeding
Hypertonic saline 23.4% Standard dose of 30 ml (120 mEq) over 15–20 min (2ml/min)
Maximum dose 60 ml		 Must be administered through a central line
Administration without a central line is an absolute contraindication
This is for acute osmotherapy with the goal of reduced ICP
Obtain serum sodium after every dose of 30 ml of 23.4% saline
Hypertonic saline 3% Mixture 3% saline (50% as acetate 50% as chloride)
Or mixture as 3% saline (100% as chloride)
Starting dose 40–50 ml/h
Titrate to serum sodium goal (140–160 meq)
Serum sodium concentration of 160 is the maximum tolerated serum sodium concentration
Common bolus volume is 250 cc		 Must be administered through a central line
Administration without a central line is an absolute contraindication
Obtain serum sodium levels every 2–4 h while infusing and immediately after bolusing
Hypertonic saline 2% Given as an IV bolus or continuous infusion
Serum sodium should be monitored every 4 h while in the infusion		 No absolute contraindications
Furosemide 10–20 mg IV q4h Titrated
Decreases edema and CSF production
Does not produce rapid decreases in ICP
Pentobarbital 3–5 mg/kg IV bolus, over 30 min then 1 mg/kg/h
Loading dose:
   10mg/kg/h for 3 h then
   2mg/kg/h		 Monitoring: EEG burst suppression, therapeutic level of 20–50 μg/ml
Burst suppression goal 1:10 to 1:30 ratio of complexes to seconds
Lidocaine 0.5–1.5 mg/kg IV or intratracheally Useful with acute airway manipulations to reduce coughing
Can precipitate seizures
Dexamethasone 4–20 mg IV q6h Decreases brain swelling with vasogenic edema
Increases mortality in head trauma
CSF, cerebral spinal fluid; EEG, electroencephalogram; ICP, intracranial pressure; IV, intravenous









TABLE 9.4. Cerebral Vasospasm
















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Jun 16, 2016 | Posted by in CRITICAL CARE | Comments Off on Neurologic and Psychiatric Therapeutics

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Goal Treatment Comments
If arterial pressure excessively elevated, lower toward normal range Trimethaphan or labetalol Refer to Tables 3.11 and 3.12; vasodilator agents may increase intracranial blood volume and intracranial pressure and are usually avoided in symptomatic vasospasm
Ensure adequate intravascular volume Colloid and/or crystalloid solutions as appropriate Fluids maximize cardiac performance and blunt catecholamine release and activation of renin-angiotensin system; if cerebral edema is severe, may need invasive monitoring
Avoid arterial hypotension