The therapeutic range is 10-20 mcg/mL. Total phenytoin levels (mcg/mL) and typical corresponding signs and symptoms are as follows: Lower than 10 – Rare.
Contents
- 1 What should your Dilantin level be?
- 2 What is a toxic level of Dilantin?
- 3 What happens when your Dilantin level is too high?
- 4 How do you interpret phenytoin levels?
- 5 What does a low phenytoin level mean?
- 6 What causes low Dilantin levels?
- 7 What is a high Dilantin level?
- 8 How often should Dilantin levels be checked?
- 9 What are the symptoms of too much Dilantin?
- 10 What is the toxic level of phenytoin?
- 11 What are the usual signs of acute phenytoin toxicity?
- 12 What is the major concern after administering phenytoin to a patient with seizure?
- 13 How do you monitor Dilantin levels?
- 14 What is total phenytoin level?
- 15 How do you adjust phenytoin levels?
What should your Dilantin level be?
Results are given in micrograms per milliliter (μ/mL). The normal therapeutic range for children and adults is 10 to 20 μ/mL (8 to 15 μ/mL in newborns).
What is a toxic level of Dilantin?
Twenty to 30 mg/L: Nystagmus. Thirty to 40 mg/L: Ataxia, slurred speech, tremor, nausea, and vomiting. Forty to 50 mg/L: Lethargy, confusion, hyperactivity. Greater than 50 mg/L: Coma and seizures.
What happens when your Dilantin level is too high?
What is Dilantin toxicity? Dilantin, or phenytoin, toxicity happens when you have high levels of Dilantin in your body that become harmful. Dilantin is a medicine that is used to prevent and treat seizures. Dilantin toxicity can lead to a coma.
How do you interpret phenytoin levels?
Toxic phenytoin levels are defined as greater than 30 µg/mL. Lethal levels are defined as greater than 100 µg/mL. The reference range of free phenytoin is 1-2.5 µg/mL. In patients with renal failure associated with hypoalbuminemia, free phenytoin levels may be more accurate than total phenytoin levels.
What does a low phenytoin level mean?
Phenytoin blood testing is ordered because phenytoin blood levels must be maintained within a narrow therapeutic range. If levels are too low, the affected person may experience seizures; if they are too high, the person may experience symptoms associated with phenytoin toxicity.
What causes low Dilantin levels?
Drugs which may decrease phenytoin levels include: carbamazepine, chronic alcohol abuse, reserpine, and sucralfate. Moban® brand of molindone hydrochloride contains calcium ions which interfere with the absorption of phenytoin.
What is a high Dilantin level?
At serum levels of 30 ug/mL, the drug is toxic in up to 50% of patients. The first sign of toxicity is usually nystagmus, which occurs at levels of 20 ug/mL. Cerebellar ataxia, tremor, and hyperreflexia occur at about 30 ug/mL and confusion, lethargy, and coma at 40 ug/mL and higher.
How often should Dilantin levels be checked?
A level can be taken 2-4 hours following an IV loading or top-up dose (12-24 hours for oral doses) and levels should then be monitored every 24 hours until control is achieved and concentration has stabilised.
What are the symptoms of too much Dilantin?
Symptoms
- Coma.
- Confusion.
- Staggering gait or walk (early sign)
- Unsteadiness, uncoordinated movements (early sign)
- Involuntary, jerky, repeated movement of the eyeballs called nystagmus (early sign)
- Seizures.
- Tremor (uncontrollable, repeated shaking of the arms or legs)
- Sleepiness.
What is the toxic level of phenytoin?
Signs and symptoms of phenytoin toxicity typically correspond to the serum level, and progress from occasional mild nystagmus at 10-20 mcg/mL (the therapeutic range) to coma and seizures at levels above 50 mcg/mL (see Presentation and Workup).
What are the usual signs of acute phenytoin toxicity?
Unsteady gait, dizziness/vertigo, nausea/vomiting, general weakness, and drowsiness were the most common presenting symptoms.
What is the major concern after administering phenytoin to a patient with seizure?
Nervous System: The most common adverse reactions encountered with phenytoin therapy are nervous system reactions and are usually dose-related. Reactions include nystagmus, ataxia, slurred speech, decreased coordination, somnolence, and mental confusion.
How do you monitor Dilantin levels?
Laboratories often report the value in g/L instead ( g/dL = g/L x 0.1 ). After a patient has received a loading dose of intravenous phenytoin, levels can be checked one hour after the dose. If loading is achieved by oral dosing, phenytoin levels can be checked 24 hours after the last dose10.
What is total phenytoin level?
The range for percent free phenytoin is 8% to 14%. However, response and side effects will be individual. In patients with renal failure, total phenytoin is likely to be less than the therapeutic range of 10.0 to 20.0 mcg/mL. Severe toxicity occurs when the total blood concentration exceeds 30.0 mcg/mL.
How do you adjust phenytoin levels?
A rough guide to making an adjustment to the daily dose that should increase a serum level without leading to supratherapeutic / toxic levels is: If the phenytoin concentration is < 7 mcg/mL, the dose may be increased by 100 mg/day. If the phenytoin concentration is 7-12 mcg/mL, the dose may be increased by 50 mg/day.
