Maintenance dose

Maintenance Dose is a term used in Pharmacology to refer to the dose of a drug that is required to keep the level of that drug in the body at a steady state, helping to maintain the desired level of drug effect over time. This is typically achieved after the administration of a Loading Dose, which is a higher dose given initially to quickly achieve therapeutic levels of the drug in the body.

Definition

The Maintenance Dose is the dose of a drug that maintains or keeps the level of the drug in the body at a stable or constant level over time. It is typically calculated based on the patient's weight, age, and overall health status. The maintenance dose is usually lower than the loading dose and is given at regular intervals to maintain the therapeutic level of the drug in the body.

Calculation

The calculation of the maintenance dose is based on the clearance of the drug from the body and the desired plasma concentration. The formula used is:

Maintenance Dose = (Desired plasma concentration x Clearance) / Bioavailability

Where:

• Desired plasma concentration is the target level of the drug in the blood.
• Clearance is the volume of plasma from which the drug is completely removed per unit time.
• Bioavailability is the fraction of the administered dose that reaches the systemic circulation.

Factors Affecting Maintenance Dose

Several factors can affect the maintenance dose of a drug. These include:

• Pharmacokinetics: This includes absorption, distribution, metabolism, and excretion of the drug. Changes in any of these factors can affect the maintenance dose.
• Pharmacodynamics: This refers to the relationship between drug concentration at the site of action and the resulting effect. Changes in the body's response to the drug can affect the maintenance dose.
• Patient-specific factors: These include age, weight, gender, genetic factors, and disease state. For example, patients with kidney or liver disease may require a lower maintenance dose due to decreased drug clearance.

See Also

• Loading Dose
• Therapeutic Drug Monitoring
• Pharmacokinetics
• Pharmacodynamics