From the Guidelines
Peak and trough refer to the highest and lowest levels of a substance in the body, typically used when discussing medication concentrations in the bloodstream. The peak is the maximum concentration reached after taking a dose, usually occurring shortly after administration. The trough is the minimum concentration, typically measured just before the next scheduled dose. These measurements are important for medications where maintaining certain blood levels is critical for effectiveness and safety, such as antibiotics, anticonvulsants, and immunosuppressants. For example, with vancomycin (an antibiotic), doctors might target peak levels of 20-40 μg/mL and trough levels of 10-20 μg/mL for serious infections, as suggested by the Infectious Diseases Society of America 1. Monitoring these levels helps ensure the medication remains effective without reaching toxic concentrations. If levels are too low at the trough, the medication may be ineffective; if too high at the peak, side effects or toxicity may occur. The concepts of peak and trough apply to many biological processes beyond medications, including hormone levels and blood glucose.
Key Points to Consider
- Peak levels are typically measured after administration of a dose
- Trough levels are measured just before the next scheduled dose
- Target peak and trough levels vary by medication and condition being treated
- Monitoring peak and trough levels is crucial for medications with narrow therapeutic indexes, such as vancomycin 1
- Adjusting doses based on peak and trough levels can help minimize toxicity and maximize efficacy, as recommended by the British Thoracic Society 1
Clinical Application
In clinical practice, monitoring peak and trough levels is essential for ensuring the safe and effective use of certain medications. By adjusting doses based on these levels, healthcare providers can minimize the risk of toxicity and maximize the therapeutic benefit of the medication. For example, the British Thoracic Society recommends targeting trough levels of less than 5 mg/L and peak levels of 25-35 mg/L for certain medications 1. By following these guidelines and monitoring peak and trough levels closely, healthcare providers can provide optimal care for their patients.
From the FDA Drug Label
When monitoring gentamicin peak concentrations, dosage should be adjusted so that prolonged levels above 12 mcg/mL are avoided. When monitoring gentamicin trough concentrations, dosage should be adjusted so that levels above 2 mcg/mL are avoided
- Peak refers to the highest concentration of gentamicin in the blood, usually occurring after administration of the drug.
- Trough refers to the lowest concentration of gentamicin in the blood, usually occurring just before the next dose is administered. The goal is to maintain peak levels below 12 mcg/mL and trough levels below 2 mcg/mL to minimize the risk of toxicity 2.
From the Research
Definition of Peak and Trough
- Peak refers to the highest concentration of a substance, such as a drug, in the blood or other fluid [ 3 ].
- Trough refers to the lowest concentration of a substance, such as a drug, in the blood or other fluid [ 3 ].
Measurement of Peak and Trough Concentrations
- Peak concentrations are typically measured after administration of a drug, when its concentration in the blood or other fluid is at its highest [ 4 ].
- Trough concentrations are typically measured just before administration of the next dose of a drug, when its concentration in the blood or other fluid is at its lowest [ 5 ].
Importance of Peak and Trough Concentrations
- Measuring peak and trough concentrations is important for ensuring that drug concentrations remain within a therapeutic range, minimizing the risk of toxicity or ineffective treatment [ 6 ].
- Peak and trough concentrations can be used to adjust drug dosing regimens and optimize treatment outcomes [ 7 ].