When should phenytoin trough levels be taken?

A trough level ( i.e. sample prior to next dose) should be taken 5 days after commencing maintenance therapy or after a change in dose. A second sample should then be taken after a further 10 days as further accumulation may occur7,8.

Is phenytoin a trough level?

Serum trough values are recommended to establish and monitor phenytoin dosage regimens. Trough levels are preferred over peak levels. The recommended sampling time for trough levels is immediately preceding the next dose. Steady state levels are reached after 7 to 10 days of treatment.

What level should phenytoin?

Obtain a serum phenytoin level. The therapeutic range is 10-20 mcg/mL.

When do you give 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.

Is phenytoin a high risk medication?

The high-alert medications were: amiodarone, digoxin, dopamine, epinephrine, fentanyl, gentamycin, heparine, insulin, morphine, norepinephrine, phenytoin, potassium, propofol and tacrolimus.

What is normal free phenytoin level?

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. However, the Sheiner-Tozer formula (below) can be used to correct the phenytoin level.

When to draw a phenytoin level?

Phenytoin levels should be checked at specific times. Testing should be done a week to 10 days after treatment has started. Levels should be tested at regular intervals of at least once a month to ensure consistency. Additionally, if dosages are increased or decreased, testing should be done within a week of the adjustment.

What are appropriate phenytoin levels?

The normal therapeutic range for adults, who are consuming phenytoin is between 10.0-20.0 mcg/mL. As long as the drug remains within this range, there will be no side effects or other symptoms.

What is a trough drug level?

In medicine and pharmacology, a trough level or trough concentration ( Ctrough) is the lowest concentration reached by a drug before the next dose is administered, often used in therapeutic drug monitoring. The name comes from the idea that on a graph of concentration versus time, the line forms a U-shaped trough at…

What is peak and trough in medical terms?

A trough level is contrasted with a “peak level”, which is the highest level of the medicine in the body, and the “average level”, which is the mean level over time. It helps in therapeutic drug monitoring. It is widely used in clinical trials for newer medicines for its therapeutic effectiveness and safety.