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Peak and Trough Sampling Times
To assess drug concentrations during the trough phase, blood should be drawn immediately before the next dose.
To assess peak levels, the time for drawing depends on the route of administration:
- Oral: One hour after drug is taken (assumes a half-life of > two hours)
- IV: 15-30 minutes after injection/infusion
- Intramuscular (IM): 30 minutes - one hour after injection
How do you calculate when to collect a peak blood collection?
To assess peak levels, the time for drawing depends on the route of administration: Oral: One hour after drug is taken (assumes a half-life of > two hours) IV: 15-30 minutes after injection/infusion. Intramuscular (IM): 30 minutes - one hour after injection.
When should a peak level be drawn?
A trough level is drawn immediately before the next dose of the drug is administered. A peak level is drawn 1 to several hours after the drug is administered (depending on the drug).
Why do we measure peak and trough?
Peak and trough levels indicate drug levels in an individual's body. A peak is the highest level of a medication in the blood, while a trough level indicates the lowest concentration. Troughs of medication concentration occur after the drug has been broken down and metabolized by the body.
When the peak level of a medication is reached what happens to that medication?
After taking a drug, levels peak quickly then drop slowly as the drug is eliminated (cleared from the body) – every drug has its own absorption curve. The highest concentration is called the Cmax. The time taken to reduce the highest concentration by half (by 50%) is called a drug's 'half-life' or T½.