Pharmacologic Principles
Pharmaceutics – drug into body (disintegration of dosage form dissolution in the body)
Pharmacokinetics – what body does to the drug (absorption, distribution, metabolism, excretion)
Pharmacodynamics – what drug does (drug receptor interaction)
Pharmacotherapeutics – how does the med work
First Pass Effect Non First Pass Effect
Oral Buccal/SL
NG/DHT/FT/G-tube Inhaled
Hepatic Artery IV, IM, SQ, Vaginal
Rectal Intra nasal, transdermal
Lifespan Considerations
Pregnancy
- 1st trimester is greatest danger for drug induced developmental defects
- Drugs cross the placenta by diffusion
- Last trimester the greatest percentage of maternally absorbed drug gets to the fetus
- FDA is changing pregnancy safety categories
Neonatal and Pediatrics
Absorption
- Gastric pH is less acidic
- Gastric emptying slowed
- IM absorption is faster and irregular
- First pass elimination is reduced
Distribution
- The younger the person the greater the % of total body water
- Lower fat content
- Decreased level of protein binding
- Immature blood brain barrier
Metabolism
- Liver immature
- Older children have increased metabolism
Excretion
- Kidney immaturity affects GFR and tubular secretion
- Decreased perfusion rate of the kidneys may reduce excretion of drugs
,Elderly
Absorption
- Gastric pH less acidic
- Gastric emptying slowed
- Movement through GI tract is slowed
- Blood flow slowed to GI tract
Distribution
- Decreased % body water
- Increased overall body fat content
- Decreased production of proteins by liver
- Decreased protein binding drugs (increased free drug)
Metabolism
- Aging liver produces fewer microsomal enzymes affecting drug metabolism
- Reduced blood flow to liver
- Decreased metabolism
Excretion
- Decreased # of intact nephrons
- Decreased blood flow
- Decreased function
- Decreased GFR
- Decreased excretion
Fluid and Electrolytes
Diffusion
- High à low
- NO ENERGY REQUIRED
Facilitated Diffusion
- High à low
- NO ENERGY NEEDED
Active Transport
- Low à high
- ENERGY NEEDED (ATP)
Osmosis
- Low à high
- Dilute à concentrated
- NO ENERGY NEEDED
- ECF = ICF à ISOTONIC
- ECF < ICF à HYPOTONIC
- ECF > ICF à HYPERTONIC
,Crystalloids
- Water and electrolytes
- Used for dehydration, maintenance, weeping wounds
- NO PROTEIN
- Ex. ) 0.9% NS, 0.45% NS, 3% NS, Lactated ringers, D5W, D5 0.45 NS, Plasmalyte
Hypotonic IV Solutions
- Water > electrolytes
- Dilutes fluid OUTSIDE of cell
- ECF = ICF
- Ex.) D5W, 0.45% NaCl
- DOES NOT REPLACE ELECTROLYTES
Isotonic Solutions
- Fluid replacement
- Used for low sodium, dehydration
- Ex.) Lactated ringers, 0.9% NaCl
- CONTAINS ELECTROLYTES
Hypertonic IV Solutions (SUPER SALTY)
- Treats HYPOvolemia and HYPOnatremia
- Ex.) 3% NaCl, D5 ½ NS, D5W NS, and D10
Colloids
- GIVE WHEN PROTEIN IS LOW
- Ex.) Albumin, Dextran, Hetastarch
Blood Products
- CAN CARRY OXYGEN
- Ex.) PPF – in patients who are at risk for bleeding, FFP – HAS clotting factors, PRBCs –
anemia, acute blood loss
, HYPOKALEMIA < 3.5
Causes: Burn, loop diuretics, vomiting, diarrhea,
alkalosis, corticosteroids, ketoacidosis
Clinical Manifestations: Muscle weakness, muscle cramping, weak
irregular pulse, PVC’s, weak hand grips,
lethargy
Treatment: Potassium chloride tablets, 40mEq oral,
20mEq central line, 10 MEq peripheral IV
NEVER BOLUS
HYPERKALEMIA >5
Causes: Supplements, ACE inhibitors, potassium
sparing diuretics, metabolic acidosis,
infections, renal failure
Clinical Manifestations: Muscle weakness, abdominal cramping,
diarrhea, irregular pulse, dysrhythmias,
cardiac arrest
Treatment: Kayexalate, Dialysis, Diuretic therapy, Insulin
à dextrose à sodium bicarb, IV calcium
HYPONATREMIA < 135
Causes: Diarrhea, vomiting, renal disorder, diuretics,
burns, wound drainage, fasting diets,
excessive water gain
Clinical Manifestations: Irritability, confusion, muscle cramps,
lethargy, nausea, vomiting, tremors, seizures,
coma
Treatment: Fluid restriction, oral sodium chloride, 3%
NaCl
HYPERNATREMIA >145
Causes: Excessive sodium intake, near drowning in
salt water, inadequate water intake, excessive
water loss, poor renal excretion
Clinical Manifestations: Muscle weakness, lethargy, red flushed skin,
decrease UO
Treatment: Water replacement, D5W, 0.45% NS
Pharmaceutics – drug into body (disintegration of dosage form dissolution in the body)
Pharmacokinetics – what body does to the drug (absorption, distribution, metabolism, excretion)
Pharmacodynamics – what drug does (drug receptor interaction)
Pharmacotherapeutics – how does the med work
First Pass Effect Non First Pass Effect
Oral Buccal/SL
NG/DHT/FT/G-tube Inhaled
Hepatic Artery IV, IM, SQ, Vaginal
Rectal Intra nasal, transdermal
Lifespan Considerations
Pregnancy
- 1st trimester is greatest danger for drug induced developmental defects
- Drugs cross the placenta by diffusion
- Last trimester the greatest percentage of maternally absorbed drug gets to the fetus
- FDA is changing pregnancy safety categories
Neonatal and Pediatrics
Absorption
- Gastric pH is less acidic
- Gastric emptying slowed
- IM absorption is faster and irregular
- First pass elimination is reduced
Distribution
- The younger the person the greater the % of total body water
- Lower fat content
- Decreased level of protein binding
- Immature blood brain barrier
Metabolism
- Liver immature
- Older children have increased metabolism
Excretion
- Kidney immaturity affects GFR and tubular secretion
- Decreased perfusion rate of the kidneys may reduce excretion of drugs
,Elderly
Absorption
- Gastric pH less acidic
- Gastric emptying slowed
- Movement through GI tract is slowed
- Blood flow slowed to GI tract
Distribution
- Decreased % body water
- Increased overall body fat content
- Decreased production of proteins by liver
- Decreased protein binding drugs (increased free drug)
Metabolism
- Aging liver produces fewer microsomal enzymes affecting drug metabolism
- Reduced blood flow to liver
- Decreased metabolism
Excretion
- Decreased # of intact nephrons
- Decreased blood flow
- Decreased function
- Decreased GFR
- Decreased excretion
Fluid and Electrolytes
Diffusion
- High à low
- NO ENERGY REQUIRED
Facilitated Diffusion
- High à low
- NO ENERGY NEEDED
Active Transport
- Low à high
- ENERGY NEEDED (ATP)
Osmosis
- Low à high
- Dilute à concentrated
- NO ENERGY NEEDED
- ECF = ICF à ISOTONIC
- ECF < ICF à HYPOTONIC
- ECF > ICF à HYPERTONIC
,Crystalloids
- Water and electrolytes
- Used for dehydration, maintenance, weeping wounds
- NO PROTEIN
- Ex. ) 0.9% NS, 0.45% NS, 3% NS, Lactated ringers, D5W, D5 0.45 NS, Plasmalyte
Hypotonic IV Solutions
- Water > electrolytes
- Dilutes fluid OUTSIDE of cell
- ECF = ICF
- Ex.) D5W, 0.45% NaCl
- DOES NOT REPLACE ELECTROLYTES
Isotonic Solutions
- Fluid replacement
- Used for low sodium, dehydration
- Ex.) Lactated ringers, 0.9% NaCl
- CONTAINS ELECTROLYTES
Hypertonic IV Solutions (SUPER SALTY)
- Treats HYPOvolemia and HYPOnatremia
- Ex.) 3% NaCl, D5 ½ NS, D5W NS, and D10
Colloids
- GIVE WHEN PROTEIN IS LOW
- Ex.) Albumin, Dextran, Hetastarch
Blood Products
- CAN CARRY OXYGEN
- Ex.) PPF – in patients who are at risk for bleeding, FFP – HAS clotting factors, PRBCs –
anemia, acute blood loss
, HYPOKALEMIA < 3.5
Causes: Burn, loop diuretics, vomiting, diarrhea,
alkalosis, corticosteroids, ketoacidosis
Clinical Manifestations: Muscle weakness, muscle cramping, weak
irregular pulse, PVC’s, weak hand grips,
lethargy
Treatment: Potassium chloride tablets, 40mEq oral,
20mEq central line, 10 MEq peripheral IV
NEVER BOLUS
HYPERKALEMIA >5
Causes: Supplements, ACE inhibitors, potassium
sparing diuretics, metabolic acidosis,
infections, renal failure
Clinical Manifestations: Muscle weakness, abdominal cramping,
diarrhea, irregular pulse, dysrhythmias,
cardiac arrest
Treatment: Kayexalate, Dialysis, Diuretic therapy, Insulin
à dextrose à sodium bicarb, IV calcium
HYPONATREMIA < 135
Causes: Diarrhea, vomiting, renal disorder, diuretics,
burns, wound drainage, fasting diets,
excessive water gain
Clinical Manifestations: Irritability, confusion, muscle cramps,
lethargy, nausea, vomiting, tremors, seizures,
coma
Treatment: Fluid restriction, oral sodium chloride, 3%
NaCl
HYPERNATREMIA >145
Causes: Excessive sodium intake, near drowning in
salt water, inadequate water intake, excessive
water loss, poor renal excretion
Clinical Manifestations: Muscle weakness, lethargy, red flushed skin,
decrease UO
Treatment: Water replacement, D5W, 0.45% NS
