Nursing interactions with Pharmacology

This is my overview of two early topics in nursing Pharmacology. It is my first real post and I will continue to change the duration of each post and the information density to get you guys the best content possible. If there are any issues or corrections let me know and i will change them. Also i am not a doctor or offering health care advice, these are just my nursing notes here to help you do better in nursing school.

– 5 rights plus many more extras that were added recently.

  • Administration, drug, patient, dose, route, time.
  • assessment, documentation,evaluation, education, and right to refuse medication or procedure

– Patient care

  • Pre-administration – before any interventions are prescribed
    • The nurse will go through their assessments finding the patient’s baseline. (basic and focused if needed) ie. Vitals, LOC,
    • Know and identify risk factors for the drug and the patient: disease that creates poor metabolism, drug interactions, allergies.
    • See if the patient will comply with the treatment and identify reasons that the patient may not beable to follow through with the prescription
  • Dose –
    • Know the indications and contraindications
    • A single drug can have multiple therapeutic ranges depending on the desired effect.
    • the dose will change with the route of administration
    • Pay extremely close attention to the label!
      • Expiration, concentration, and double check your dose calculations with route and concentration.
  • Therapeutic response (TPR) – the desired degree of the signs and symptoms a drug is showing
    • If there are no signs of the TPR then there is often an issue that needs to be addressed with the administration of the drug immediately
    • Things that affect the TPR –
      • Patient adherence – if the patient will follow through, not adhering decreases the TPR
      • Non drugs that increase TPR can be diet and exercise and can improve patient outcomes.
      • know the s/s of a patient that is falling out of the TPR and what to do if they are experiencing toxicity.
        • What to do, and when to do it.
      • PRN – as needed,
  • The nursing process quick:
    • Assessments – basic and focused
    • Analysis – what do you think the cause is, what is wrong, s/s,
    • Planning – Write care plan with goals, priorities, and interventions recommended.
    • Application of plan – Follow through with Care plan,
    • reassess and monitor – what was the degree of success of the plan?
      • what do we need to do next and how can we deal with issues in the CP that we found in the application?
      • Monitor the TPR, interactions, minimize the toxicity and Adverse effects of the drug


Pharmacokinetics

  • A drug’s movement through the body
    • Membranes-
      • Channel pores – these are very small and only allow very small molecules like Na and K to go through
      • Transport systems – carry the molecule across a membrane. These can be active which require energy, or passive which do not. These are also very selective in the way that they only transport  specific drugs.
      • P- Glycoprotein – this protein crosses the membrane and moves drugs out of the cell. it is also called a multidrug transporter protein, these exist in the liver excreting bile and in the kidneys excreting urine, they also are in the brain, placenta and intestines.
      • Direct penetration of the membrane – this is common system of pharmacokinetics. many drugs use this system because they are too large to pass though the other systems or do not have a specific structure to facilitate the transport system. a drug that passes through a membrane this way must be lipid soluble ie. not polar or an ion.
      • Polar molecules – uneven distribution of charge but no net charge
        • ie. Water
      • Ions – Have a net charge and most (except for the smallest) cannot pass through membranes.
        • Quaternary Ammonium Compounds – net positive charge and at least one nitrogen.
        • pH- dependent – Weak acids give up a proton in basic environments to become ionized and weak bases take a proton in acidic environments to become ionized.
        • Ion trapping due to pH imbalances – if one side of a membrane is acidic it will tend to ionize the basic drugs and trap them. If the other side is basic it will tend to ionize and prohibit acidic drugs from crossing.
    • Absorption an factors that regulate it.
      •  How fast the drug dissolves
        • faster is faster
      • the amount of receptors or surface area that the drug can absorb through
        • More is faster
      • Higher blood flow equals more drug to the cite and more absorption
      • Lipid soluble drugs absorb faster
      • pH differences increase the absorption if the drug ionizes in the plasma
    • Enteral route
      • oral – (PO) it can be a slow route and must go through the GI tract and the capillaries. This leads to variability in the absorption rates and can be affected by many things: pH, GI absorption, nausea and vomiting , and pt needs to have patient airway.
    • Parenteral
      • IV – Instant and no barriers to absorption, very precise control of amount, and can push drugs that would irritate patient otherwise.  It is irreversible and a patient cannot do it by themselves.
      • Intramuscular and subcutaneous – (IM) (subQ)must absorb through capillary wall, can use poorly soluble drugs, but it can possibly injure the patient.
  • Distribution –
    • Blood flow – decreases inside a solid tumor, and abscesses, which have no blood flow inside the structure.
    • Exiting the blood flow (vasculature)
      • – Capillary beds – most common and easy, the drug passes through the pores in the vessel wall.
      • Blood brain barrier – less common and hard to get through due to the tight junctions. Only lipid soluble and drugs that can utilize a transport system can pass through.
      • The Placenta – not a complete barrier to drug distribution and relatively weak, the same rules that allow drugs to cross a membrane apply to the placenta .
  • Metabolism – the enzymatic change of the drug structure, usually happens in the liver.
    • changes in metabolism can increase secretion, toxicity, Therapeutic action, decrease toxicity, activation and activation of pro drugs.
  • Excretion – removal of drugs from the patient. happens in three steps in the kidneys
    • glomerular filtration – the first step from moving the drug from the blood stream into
    • passive tubular reabsorption – lipid soluble move out and ionized stay in the
    • active tubular secretion – from the blood to the urine using active transport.
    • non-renal
      • Breast milk
      • bile
      • small amounts in the sweat and saliva.
  • Time related to the drug response
    • Plasma drug levels –
      • minimum effective concentration, the amount of the drug that brings the effect into the therapeutic range.
      • Therapeutic range, enough to get a response but not enough to be toxic.
      • Toxic concentration, the highest level of the range were negative or toxic effects occur.
      • Half life – the amount of time it takes for 1/2 of the drug to decrease by 50%
      • repeated doses will allow for the TP effects to plateau and stay consistent with the drug accumulation.
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