Drug Dosage and Blood Concentration – therapeutic range

Drug Dosage and Blood Concentration – therapeutic range

1. the goal of drug dosing is to give a dose that places the drug concentration above the MEC but below the level at which adverse effects occur

2. the drug blood level is only one piece of data that must be considered when evaluating the patient's response to drug therapy

A Nurse's Role in Monitoring Drug Blood Levels

1. notify the physician or nurse practitioner if the level indicates that the patient is not in the therapeutic range or is greatly above the therapeutic range

2. if a patient appears to be experiencing adverse effects

3. if is important to note the exact time the last dose of the drug was administered on the drug blood level specimen slip

Adverse Effects – undesirable effect other than the intended therapeutic effect

can check "trough" - check blood 30 minutes prior to medication dose and then check "peak" after dose is given

Drug interaction: occurs when two drugs or a drug and another element (such as food) have an effect on each other

*Minimize adverse effects & maximize positive effects, plan for pt education

Adverse Effects – Nurses need to understand adverse effects and drug interactions and use this knowledge in their management of drug therapy.

Two types of adverse effects:

1. mild adverse effects, such as nausea, are bothersome perhaps only to the pt

2. serious adverse effects, such as liver failure, are life threatening

Determining Adverse Effects

1. It is important for nurses and other health care professionals to be alert for adverse effects from drug therapy.

2. Adverse effects may be mistaken for changes associated with aging or disease pathology.

Adverse Effects – Not predictable or dose related – Allergic Response

1. an allergic response is an immune system response

2. symptoms of allergy due to release of histamine

3. redness, itching, swelling, rash, hives

4. most serious allergic response is called anaphylaxis (breathing shuts down, death can follow)

Adverse Effects – Not predictable or dose related – Idiosyncratic Response

1. related to the individual rather than dose-related

2. idiosyncratic responses (sometimes called paradoxical effects) to a drug are unusual and in fact may be the opposite of what is anticipated

Adverse Effects – toxicities

1. specific patterns or groups of symptoms related to drug therapy that carry risk for permanent damage or death are called toxicities

2. the organ or system that is affected is used to name the toxicity, ie. neurotoxicity, nephrotoxicity, cardiotoxicity, hepatotoxicity, ototoxicity, and immunotoxicity

Neurotoxicity – sometimes referred to as CNS toxicity, it is a drug's ability to harm or poison a nerve cell or nerve tissue (alkaloids for chemotherapy, such as vincristine can cause irreversible damage and can affect pt's ability to lift feet)

1. injury to the CNS is largely irreversible because the highly differentiated neurons of the brain cannot divide and regenerate

2. immature nervous systems (ie. fetal and neonate nervous systems) can easily be damaged by drugs that produce neurotoxicity