Although the reference range is between 10 and 20 µg/mL, about half of patients' seizures are controlled at values lower and higher than the therapeutic range. Some adverse effects of phenytoin are related to specific serum levels. Nystagmus is frequently observed at levels greater than 20 µg/mL.
Also to know is, what is the normal range for Dilantin levels?
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. Between 10 and 20 - Occasional mild nystagmus.
Secondly, what does high phenytoin level mean? The neurotoxic effects are concentration dependent and can range from mild nystagmus to ataxia, slurred speech, vomiting, lethargy and eventually coma and death. Paradoxically, at very high concentrations, phenytoin can lead to seizures. Greater than 50 mg/L: Coma and seizures.
Secondly, when should a phenytoin level be drawn?
In these situations of routine monitoring (unlike the emergency situation of breakthrough seizures in scenario two), it is preferable to draw the phenytoin level just prior to the next dose (a trough level) or at least eight hours after the last dose10,11.
What happens when your Dilantin level is too high?
Dilantin Toxicity Serious toxicity can occur in people who take Dilantin. This is more likely to happen when doses are increased or other medications are started or stopped. Common symptoms of Dilantin toxicity include dizziness, drowsiness, coordination problems, rapid eye movements, and extreme fatigue.
How do I lower my phenytoin level?
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 happens if phenytoin is low?
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 phenytoin levels?
Patients with unusually low levels may be noncompliant or hypermetabolizers of phenytoin. Unusually high levels result from liver disease, congenital enzyme deficiency or drug interactions which result in metabolic interference.How long does phenytoin stay in your system?
Oral Administration This means that about half of the drug is eliminated from the body in four hours, although some of the drug is expected to remain in your body for two to three days.What happens if you take too much phenytoin?
An overdose of phenytoin can be fatal. Overdose symptoms may include twitching eye movements, slurred speech, loss of balance, tremor, muscle stiffness or weakness, nausea, vomiting, feeling light-headed, fainting, and slow or shallow breathing. Avoid drinking alcohol while you are taking phenytoin.Does Dilantin cause brain damage?
Multiple studies have shown that Dilantin, a commonly prescribed antiepileptic drug, may increase the risk of experiencing brain damage or the death of nerve cells in the brain. Dilantin long term side effects may include cerebellar atrophy or degeneration.What is phenytoin toxicity?
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.What can affect Dilantin levels?
Alcohol use can increase your blood levels of phenytoin and may increase side effects. Daily alcohol use can decrease your blood levels of phenytoin, which can increase your risk of seizures. Avoid taking antacids at the same time you take Dilantin. Antacids can make it harder for your body to absorb the medication.How do you calculate phenytoin levels?
If you are a human and are seeing this field, please leave it blank. If clcr < 20 mL/min then Corrected Phenytoin = Total Phenytoin Level / ( (0.1 x albumin) + 0.1) This is so cool!How do I start phenytoin?
Phenytoin typical doses are 3–5mg/kg/day. The first dose should be given 12–24 hours after the loading dose. Oral or nasogastric administration should be used, whenever possible. Only use intravenous administration when these options are not feasible and where cardiac monitoring is available.How does low albumin affect phenytoin levels?
The concentration of albumin in serum is decreased with inflammation, chronic liver disease, or malnutrition. The presence of hypoalbuminemia is known to reduce the protein binding of phenytoin in plasma,8,10 and both the ratio of free/total phenytoin concentration and the total phenytoin concentration may be altered.What are the side effects of phenytoin?
Side Effects. Headache, nausea, vomiting, constipation, dizziness, feeling of spinning, drowsiness, trouble sleeping, or nervousness may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly. Phenytoin may cause swelling and bleeding of the gums.When should phenytoin be corrected for albumin?
Phenytoin (Dilantin) Correction for Albumin / Renal Failure. Corrects serum phenytoin level for renal failure and/or hypoalbuminemia. Use in patients with albumin ≤3.2 g/dL (32 g/L). The “Sheiner-Tozer Equation” is the official name of this correction.Does Dilantin make you tired?
Dilantin may cause drowsiness, dizziness or sleepiness in some people and affect alertness. Be careful when drinking alcohol while taking Dilantin. Combining Dilantin and alcohol can make you more sleepy, dizzy or lightheaded.What drugs interact with phenytoin?
Drugs That Affect Phenytoin Concentrations| Interacting Agent | Examples |
|---|---|
| Drugs that may increase phenytoin serum levels | |
| Antiepileptic drugs | Ethosuximide, felbamate, oxcarbazepine, methsuximide, topiramate |
| Azoles | Fluconazole, ketoconazole, itraconazole, miconazole, voriconazole |
| Antineoplastic agents | Capecitabine, fluorouracil |
