Chapter 3

1. I.        Medications and Calculations2. A.      Systems of Measurements

-          There are 3 systems of measurements

Metric system o Was developed in the late 18th centuryo The internationally accepted system of measure

Apothecary system Was replaced by the metric system Dates back to the middle ages and had been used in England since the 17th

century. Household system

Commonly used in community and home settings.

 

Metric System

-          The metric system is a decimal system based on the power of 10.

-          The basic units of measure are gram (g, gm, G, Gm) for weight; liter (l, L) for volume; and meter (m, M) for length.

Unit Names and Abbreviations MeasurementsGram (weight) 1 kilogram (kg, Kg) 1000 g  1 gram (g, gm, G, Gm) 1 g  1 milligram (mg) 0.001 g  1 microgram (mcg) 0.000001 g  1 nanogram 0.000000001 gLiter (volume) 1 iloliter (kl, Kl) 1000 L (l)  1 liter (L, l) 1 L (l)  1 milliliter (ml) 0.00 L (l)Meter (length) 1 kilometer (km) 1000 m  1 meter (m, M) 1 m  1 centimeter (cm) 0.01 m  1 millimeter (mm) 0.001 m

 

Apothecary System

-          Common system used by most practitioner s before the universal acceptance of the International Metric System

-          Now all pharmaceuticals are manufactured using the metric system, and the apothecary system is no longer included on any drug labels.

-          All medication should be prescribed and calculated using metric measures, but occasionally the use of the fluid ounce and grains is found. For those rare circumstances, nurses should have a general understanding of the apothecary system.

-          The apothecary system uses Roman numerals instead of arbic numbers to express the quantity. The roman numeral is placed after the symbol or abbreviation for the unit of measure.

Ex. gr x stands for 10 grains.

-          In the apothecary system, the unit of weight is the grain (gr), and the units of fluid volume are the ounce (fluidounce), the dram (fluidram), and the minim (min).

 

Dry Weight Fluid VolumeLarger Units Smaller Units Larger Units Smaller Units

1 ounce (oz) 480 grains (gr) 1 quart (qt) 2 pints (pt)1 ounce (oz) 8 drams (dr) 1 pint (pt) 16 fluid ounces1 dram (dr) 60 grains (gr) 1 fluid ounce 8 fluid dram (fl dr)1 scruple 20 grains (gr) 1 fluid dram 60 minims (min, or m)    1 minim 1 drop (gt)

 

Household System

-          Uses household containers such as spoons, cups and glasses as measuring devices.

-          Not as accurate as metric system  because of the lack of standardization.

Household Equivalents in Fluid Volume1 measuring cup 8 ounces (oz)1 medium size glass (tumbler size) 8 ounces (oz)1 coffee cup (c) 6 ounces (oz)1 ounce (oz) 2 tablespoon (T)1 tablespoon (T) 3 teaspoons (t)1 teaspoon (t) 60 drops (gtt)1 drop (gt) 1 minim (min, or m)

 

Approximate Metric, Apothecary, and Household Equivalents  Metric System   Apothecary

SystemHousehold System

Weight 1 kg 1000 g 2.2 lb 2.2 lb  1 g 1000mg 15 (16) gr    0.5 g 500 mg 7 ½ gr    0.3 g 300 (325) mg 5 gr    0.1 g 100 mg 1 ½ gr    0.06 g 60 (65) mg 1 gr    0.03 g 30 (32) mg ½ gr    0.01 g 10 mg 1/6 gr      0.6 mg 1/100 gr      0.4 mg 1/150 gr      0.3 mg 1/200 gr  Volume 1 L; 1000 ml   1 qt; 32 oz (fl oz)    0.5 L; 500 ml   1 pt; 16 oz (fl oz)    0.24 L; 240 ml   8 fl oz 1 glass  0.18 L; 180 ml   6 fl oz 1 c  30 ml   1 fl oz; 8 fl dr 2 T; 6 t  15 ml   ½ fl oz; 4 fl dr 1 T; 3 t  5 ml     1 t  4 ml   1 fl oz; 60 m (min) 1 t  1 ml   15 (16) m 15-16 gttHeight/Distance 2.54 cm   1 in 1 in  25.4 mm   1 in 1 in

 

1. Methods for Calculation

-          The four general methods for the calculation of drug dose are the (1) basic formula, (2) ration and proportion, (3) fractional equation, (4) and dimensional analysis.  These methods are used to calculate oral and injectable drug doses.

-          For drugs that require individualized dosing, calculation by body weight (BW) or by body surface area (BSA) may be necessary.

-          Before calculating drug doses, all units of measure must be converted to a single system.

Interpreting Oral and Injectable drug Labels

-          Pharmaceutical companies usually label their drugs with the brand name of the drug in large letters and the generic name in smaller letters.

-          The dose per tablet, capsule, or liquid (for oral and injectable doses) is printed on the drug label.

 

1. Method 1: Basic Formula (BF)

-          The basic formula is easy to recall and is most frequently used in calculating drug dosages.

 

D x V = A

H

 

-          D = desired dose (drug dose ordered by the health care provider)

H = on hand dose (drug dose on label of container)

V = vehicle (drug form in which the drug comes (tablet, capsule, liquid)

A = the amount calculated to be given to the client

 

1. Method 2: Ratio and Proportion

-          The ratio and proportion method is the oldest method currently used in the calculation of drug dosages.

 

H        :        V    ::    D        :        x                                                    

 

-          D = desired dose (drug dose ordered by the health care provider)

H = on hand dose (drug dose on label of container)

V = vehicle (drug form in which the drug comes (tablet, capsule, liquid)

x = the amount calculated to be given to the client

 

1. Method 3: Fractional Equation

-          The fractional equation method is similar to ratio and proportion except it is written as a fraction.

H = D

V    x

 

-          H = dosage on hand

V = vehicle

 

D = desired dosage

X = unknown

 

-          Cross – multiply and solve for x

 

 

 

 

 

1. Method 4: Dimensional Analysis

-          Dimensional analysis is a calculation method known as units and conversions. The advantage of DA is that it decreases a number of steps required to calculate a drug dosage. It is set up as one equation.

 

1. Identify the unit/form (tablet, capsule, ml) of the drug to be calculated. If the drug comes in tablet, then tablet = (equal sign)

2. The known dose and unit/form from the drug label follows the equal sign.

Order:  amoxicillin 500 mg

On the drug label: 250 mg per 1 capsule

 

Capsule =         1cap

                       250 mg

 

1. The mg (250 mg) is the denominator and it must match the next numerator, which is 500 mg (desired dose or order). The NEXT denominator would be 1 or blank.

 

Capsule =       1cap       X    500 mg  =

                       250 mg               1

 

1. Cancel out the mg, 250 and 500. What remains is the capsule and 2. Answer is 2 capsules

 

1. Method 5: Body Weight

-          The body weight method of calculation allows for the individualization of the drug dose and involves the following three steps:

1. Convert pounds to kilograms if necessary (lb / 2.2 = kg)2. Determine drug dose per BW by multiplying as follows:

Drug dose x body weight = clients dose per day

1. Follow the basic formula, ratio and proportion, fractional equation, or dimensional analysis method to calculate the drug dosage.

 

1. Method 6 : Body surface area (BSA)

-          The body surface area (BSA) method is considered the most accurate way to calculate the drug dose for infants, children, older adults, nd cliets who are on antineoplastic agents or whose BW is low. The BSA, in square meters, is determined by where the person’s height and weight intersect the nomogram scale. To calculate the drug dosage the BSA method, multiply the drug dose ordered by number of square meters.

 

100 mg x 1.8 m2 (BSA) = 180 mg/day

Chapter2

Drugs and the Body   (Pharmacodynamics)

Pharmacodynamics- The study of the drug mechanisms that produce biochemical or physiologic changes in the body.- What happens to the body in response to the drug.- Interactions between chemical components of living systems & foreign chemicals including drugs that enter these systems.

A. Drug Actions:a. To replace or act as substitutes for missing chemicals.b. To increase or stimulate certain cellular activities.c. To depress or slow cellular activities.d. To interfere with the functioning of foreign cells, such as invading microorganisms or neoplasm.

B. Theories of Drug Actionsa. Drug Receptors Interaction Theoryo Receptor sites – location on a cell surface where certain molecules such as enzymes, hormones, drugs attach to interact with cell component.o Receptor sites react with certain chemicals to cause an effect within the cell.o “lock and key theory”

o Drug action may be:1. Agonist• Drugs interact directly with receptor sites to cause the same activity that natural chemicals

would cause at that site.• Ex. Insulin2. Antagonist• A drug has an affinity for a receptor but displays little or no intrinsic activity.a. Competitive antagonisto Competes with the agonist for receptor sitesb. Non-competitive antagonisto Binds to receptor sites and blocks the effects of the agonist

b. Drug Enzyme Interactionso Interferes with enzyme systems that act as catalyst from various chemical reactions.o Enzyme systems: Cascade effect; one enzyme activating another, causing cellular reaction. If single step in one of enzyme system is blocked, normal cell function is disruptedo Ex. ACE inhibitors, inhibiting the release of angiotensin converting enzyme in the lungs, preventing the conversion of Angiotensin I to Angiotensin II which is a powerful vasocontrictor, preventing an increase in blood pressure.

c. Selective Toxicityo All chemotherapeutic agent would act only on 1 enzyme system needed for life of a pathogen or neoplastic cell & will nor affect healthy cells.o Ex. Penicillin

C. Classifications of Drug Action (in terms of speed of action)a. Rapido few seconds to minutes.o intravenous, sub-lingual, inhalationb. Intermediateo 1-2 hours after administrationo intramuscular, subcutaneousc. Delayed/Slowedo Several hours after administrationo oral and rectal

D. Parameters of Drug ActionParameters – notable characteristicsa. Onset of actiono Latent period, interval between time the drug is administered and 1st sign of its effect.b. Duration of actiono Period from onset until drug effect is no longer seen.o Length of time the drug exerts pharmacologic effect.c. Peak of actiono drug reaches its highest blood / plasma concentrationd. Termination of actiono point from onset at which drug effect is no longer seen

Drugs and the Body   (Pharmacokinetics)

Drugs and the BodyI. Pharmacokinetics- The term kinetics refers to movement.- Pharmacokinetics deals with a drugs actions as it moves through the body- What happens to the drug when it enters the body.- Involves the study of the following:o Absorptiono Distributiono Metabolism/Biotransformationo Excretion

A. Absorption

- In order to reach reactive tissues, a drug must first make its way into the circulation.- Absorption refers to what happens to a drug from the time it is introduced to the body until it reaches the circulating fluids.- Drugs can be absorbed from many different areas in the body:o GITo Mucous membraneso Through the skino Through the lungso Through the muscleo Through subcutaneous tissues

a. Cell Absorption- Drugs can be absorbed into cells through various processes

1. Passive Absorption (diffusion)o Movement of drug particles from an area of higher concentration to an area lower concentration.o No energy required: occurs when smaller molecules diffuse across membraneo Stops when drug concentration on both sides of the membrane is equalo Major process through which drugs are absorbed into the bodyo Oral drugs use passive transport2. Active Absorptiono Movement of drugs particles from an area of low concentration to an area of high concentration.o Energy is requiredo Used to absorb electrolytes (Ex. sodium, potassium)o3. Pinocytosis

o Cells engulf the drug to carry it across the membrane.o Transport fat-soluble vitamins (vitamin A,D,E,K)

b. Factors Affecting Drug Absorption1. Blood Flow2. Pain3. Stress4. Foods (High fat and solid foods)5. Exercise6. Solubility7. Nature of the absorbing surface8. pH9. Concentration10. Dosage form

c. Oral Administration of Drug

B. Distribution

- Process by which drug becomes available to body fluids & tissues- The ways a drug is transported from the site of absorption to the site of action (transportation)- Happens in the circulation (circulatory system)

a. Factors Affecting Distribution1. Size of the organ2. Blood flows drug is quickly distributed to organs with large supply of blood (heart, liver, kidneys) distribution to other internal organs, skin, fat, muscle is slower3. Solubility Lipid-soluble or non lipid-soluble Lipid-soluble drugs can cross the blood-brain barrier & enter the brain4. Protein binding

b. Protein Binding- as drug travels trough the body, it comes in contract with proteins (albumin)- the drug can remain free or bind to protein- Portion of drug bound to protein is inactive, no therapeutic affect

1. Free/unbound portion (+) pharmacologic response2. Highly protein bound drug 89% of drug is bound to protein diazepam, piroxicam, valproic acid3. Moderately high protein bound drugs 61-89% bound protein Erythromycin, phenytoin

4. Moderately protein bound drugs 30-60% bound to protein aspirin, lidocaine, pindolol, theophyline

5. Low protein-bound drugs 30% bound to protein amikacin, amoxicillin

C. Metabolism/Biotransformation

- Also called detoxification.- Refers to the bodies ability to change a drug from its dosage form to a more water soluble form that can be excreted- A sequence of chemical events that change a drug to a less active form after it enters the body- Permits the body to inactivate a potent drug before it accumulates & produces toxic effects- Drugs can be metabolized several ways:o Most drugs metabolized into inactive metabolites (products of metabolism), which are then excretedo Other drugs converted to active metabolites – capable of exerting their own pharmacologic action May undergo further metabolism or may be excreted from body unchanged Prodrugs – some drugs administered as inactive drugs which don’t become active until they’re metabolized

a. Sites of Metabolism1. Liver Through the drug metabolizing enzymes (microsomal enzymes, non-microsomal enzymes) 1st pass effect/hepatic 1st pass – some drugs do not directly go into circulation but pass thru intestinal lumen to liver via portal vein2. Plasma3. Kidneys4. Membranes

b. Factors Affecting Drug Metabolism1. Diseases Liver cirrhosis and heart failure2. Genetics People metabolize drugs rapidly, other more slowly.3. Environment Smoking and stressful environment4. Age Infants have immature livers that reduce the rate of metabolism. Elderly patients experience a decline in liver size, blood flow and enzyme production that also slows metabolism5. Nutrition Liver enzymes involved in metabolism rely on adequate amounts of amino acids, lipids,

vitamins and carbohydrates.6. Insufficient amounts of major body hormones Decrease amounts of insulin and adrenal corticosteroids can reduce metabolism of drugs in the liver.

D. Excretion

- Removal of drug from the body- Is the process by which drugs are eliminated from the body- Drug is changed into inactive form & excreted by the body

a. Sites of Excretion1. Kidney Free/unbound/water soluble drugs are filtered in kidneys Protein bound drug cannot be filtered in kidney2. Lungs, exocrine (sweat, salivary, mammary) glands, skin, intestinal tract

b. Factors Affecting Excretion1. Urine pH Normal urine pH is 4 – 5.8 Acidic urine promotes elimination of weak base drugs• Ex. Cranberry juice decreases urine pH Alkaline urine promotes elimination of weak acid drugs• Ex. Nabicarbonate increases urine pH, use to eliminate as excess aspirin in the system due to overdose2. Glomerular Filtration Rate The amount of glomerular filtrate in the glomerulus• Glomerular Filtration• Passive Reabsorption• Active Secretion Nephron Glomerulus Proximal Tubule Bladder When there is a decrease in glomerular filtration rate drug excretion are slowed/impaired. Can result to drug accumulation3. Half-life Time it takes for one half of drug concentration to be eliminated. Short half-life• 4-8 hrs: given several times a day (ex. penicillin G) Long half-life• More than 12 hrs: given 2x or 1x a day (ex. digoxin)

Chapter 1

Introduction to Nursing   Pharmacology

1. I.                    Introduction to Nursing Pharmacology

 

1. A.      Introduction to Drugs

-          The human body works through a complicated series of chemical reactions and processes.

-          Drugs are chemicals that are introduce into the body to cause some sort of change.

Drugs will undergo process with in the body which involve breaking and eliminating the drugs, in turn affect the body’s complex series of chemical reactions.

-          Understanding how drugs act on the body to cause changes and applying that knowledge in the clinical setting are important aspects of nursing practice.

-          The nurse is in a unique position regarding drug therapy because nursing responsibilities include the following:

Administering drugs Assessing drug effects Intervening to make the drug regimen more tolerable Providing patient teaching about drugs and drug regimen. Monitoring the overall patient care plan to prevent medication error

-          Knowing how drugs works make these tasks easier to handle, thus enhancing drug therapy.

 

1. B.      History

o Early drug – plants, animals & mineralso 2700 BC – earliest recorded drug use found in Middle East & Chinao 1550 BC – Egyptians created Ebers Medical Papyrus

      Castor oil – laxative

      Opium – pain

      Moldy bread – wounds & bruises

Galen (131-201 AD) Roman physician; initiated common use of prescriptions 1240 AD – introduction of apothecary (pharmacy) system (Arab doctors)

1st set of drug standards & measurements (grains, drams, minims), currently being phased out

15th century – apothecary shops owned by barber, surgeons, physicians, independent merchants

18th century – small pox vaccine (by Eward Jenner, British Doctor)

Digitalis from foxglove plant for strengthening & slowing of heartbeat Vitamin C from fruits

19th century – morphine & codeine extract from opium

      Introduction of atropine & iodine

      Amyl nitrite used to relieve anginal pain

      Discovery of anesthetics (ether, nitrous oxide)

Early 20th century – aspirin from salicylic acid

                        Introduction of Phenobarbital, insulin, sulforamides

Mid 20th century

1940 – Discovery antibiotics (penicilline, tetracycline,streptomycin), antihistamines, cortisone

1950 – Discovery antipsychotic drug, antihypertensives, oral contraceptives, polio vaccine

1. C.      Pharmacology

-          Is the study of the biological effects of chemicals.

-          It is the scientific study of the origin, nature, chemistry, effects and uses of drugs.

-          In clinical practice, health care providers focus on how chemicals act on living organisms.

 

Subdivisions of Pharmacology

1. Pharmacodynamics – study of the biochemical & physiological effects of drugs & mechanisms of action

o what the drug does to the body2. Pharmacokinetics – deals with the absorption, distribution, biotransformation &

excretion of drugs

what the body does to the drug deals with beneficial effects of the drugs (medicines) source of drugs ex: penicillin from penicillium (fungi)

3. Pharmacotherapeutics – study of drugs used in the diagnosis, prevention, suppression, & treatment of diseases

4. Pharmacognosy – study of drugs in their original unaltered state; origin of drugs

5. Toxicology – study of biologic toxins: study of poison & its effects deals with deleterious effects of physical & chemical agents (including drugs) in human

Nurses deal with Pharmacotherapeutics, or Clinical Pharmacology, the branch of pharmacology that uses drugs to treat, prevent, and diagnose diseases.

Clinical Pharmacology

-          Addresses two key concerns

The drug’s effects on the body The body’s response to the drug

-          Because drug can have many effects the nurse must know which ones may occur when a particular drug is administered.

 

Effects of the Drug

1. 1.       Therapeutic Effect

-          The primary effect intended, that is the reason the drug is prescribed.

-          Also called desired effect.

1. 2.       Side Effect

-          The effect of the drug that is not intended.

-          Also called secondary effect.

1. 3.       Drug Allergy

-          The immunologic reaction to the drug.

1. 4.       Anaphylactic Reaction

-          A severe allergic reaction which usually occurs immediately following administration of the drug.

1. 5.       Drug Tolerance

-          A decreased physiologic response to the repeated administration of a drug or chemically related substance. Excessive increase in the dosage is required in order to maintain the desired therapeutic effect.

1. 6.       Drug Interaction

-          Effects of one drug are modified by the prior or concurrent administration of another drug, thereby increases or decreases the pharmacological action.

1. Drug Antagonism – the conjoint effects of two drugs is less than the drugs acting separately.

2. Summation – The combined effect of two drugs produces a result that equals the sum of the individual effect of each agent.

3. Synergism – The combined effects of drugs is greater than the sum of each individual agent acting independently.

4. Potentiation – The concurrent administration of two drugs in which one increases the effect of the other drug.

 

Therapeutic Effects of Drugs

1. 1.       Palliative

-          Relieves the symptoms of a disease but not affect the disease itself.

-          Ex. Analgesic for pain

1. 2.       Curative

-          Treats the disease condition

-          Ex. Antibiotic for infection

1. 3.       Supportive

-          Sustains body functions until other treatment of the body’s response can take over.

-          Ex Mannitol to reduce/ICP in a client for surgery due to brain tumor.

1. 4.       Substitutive

-          Replaces body fluids or substances.

-          Ex. insulin injection for diabetes mellitus

1. 5.       Chemotherapeutic

-          Destroys malignant cells

-          Ex. Cyclophophamide for cancer of the prostate gland.

1. 6.       Restorative

-          Returns the body to health.

 

1. D.      Drug Nomenclature 1. CHEMICAL NAME – atomic/molecular structure of drug

Ex. acetylsalicylic acid

1. GENERIC NAME/NON-PROPERTY NAME – original designation given to the drug when the drug company applies for approval patents

universally accepted & not capitalized; before drug becomes official, used in all countries protected by law; not capitalized ex. aspirin

1. TRADE/BRAND/PROPRIETY NAME – name given by the drug company that developed it

followed by the symbol R or TM, 1st letter is capitalized ex. Aspilet

1. E.       Sources of Drugs

1. Plants – roots, bark, sap, leaves, flowers, seeds of medicinal plants

digitalis (use as a herat stimulant) from wildflower, purple foxglove, dried leaves of plant active principles of plants

o alkaloids – alkaline in reaction, bitter in taste, powerful in physiologic activityo atropine & scopolamineo morphine sulfate, cocaine, quinine, nicotine, caffeineo procaine

o glycosides – digitaliso resin – soluble in alcohol; example – colonic irritant found in laxative cascarao gums – used in bulk-type laxatives: some used in certain skin preparations for

their soothing reliefo oils – castor oil, oil of wintergreen

2. Animal Products – from organs, organ secretion or organ cellso Used to replace human chemical not produces because of disease or genetic

problemso Thyroid drugs & growth hormones preparations – from animal thyroid &

hypothalamus tissue (many of these preparations are now created synthetically – safer & purer)

o Insulin – from pancreas of animals (hog, cattle, sheep): thru genetic engineering – cld produce human insulin by altering E. coli bacteria making it a better product without impurities that come with animal products

1. Inorganic Compounds – from free elements, both metallic & non-metallic usually in form of acids bases, salts found in food

Dilute HCI – control/prevent indigestion Calcium, aluminum, fluoride, iron, gold, potassium more potent, more stable, less toxic steroids – arthritis & other diseases sulfonamides/chemotherapeutic agents – kill microorganism slow their growth meperidine HCI (Demerol)

4. Synthetic Sources – many drugs developed synthetically after chemical in plants, animals, or environment have been screened for signs of therapeutic activity

 

1. Genetic engineering – alter bacteria to produce chemicals that are therapeutic and effective.

Reordering of genetic information enables scientists to develop bacteria that produce insulin for human.

1. Chemical alterations – Scientists alter chemical with proven therapeutic effectiveness to make it better.

Sometimes a small change in a chemical’s structure can make that chemical more useful as a drug, more potent, more stable, less toxic.

 

1. F.       Drug Classification

1. By Actiono Ant- infectives – antiseptics, disinfectants, sterilantso Antimicrobials, metabolic, diagnostic materials, vitamins & mineralso Vaccine & serums, antifungals, antihistamines, antineoplastics, antacids

2. By Body System

CNS – (+)/(-) actions of neural pathways & centers; ex. Phenobarbital ANS – governs several bodily functions so that drugs that affect ANS will at the same

time affect other systems functions; ex. scopolamine GIT – acts on muscular & glandular tissues; ex. loperamide Respiratory System – act on resp. tract, tissues, cough center, suppress, relax, liquefy &

stimulate depth & rate of respiration; salbutamol Urinary system – act on kidney & urinary tract; ex. furosomide Circulatory system – act on heart, blood vessels, blood;  ex. Metroprolol

 

1. G.     Kinds of Drugs2. 1.       Prescription Drugs

-          Also known as legend drugs

-          Can be dispensed if with prescription order; with specific name  of drug & dosage regimen to be used by patient.

1. 2.       Non-Prescription Drugs

-          Also known as Over – the – Counter Drugs

-          can be dispensed without prescription order

-          for self treatment of variety of complaints

-          vitamin supplements, cold/cough remedies, analgesics, antacids, herbal products

 

Cautions in use of OTC drugs:

1. Delay in professional diagnosis & treatment of serious/potentially serious condition may occur

2. Symptoms may be masked making the diagnosis more complicated3. Clients’ health care provider/pharmacist should be consulted before OTC preparations are

taken4. Labels/instructions should be followed carefully5. Ingredients in OTC drug may interact with prescribed drug

6. Inactive ingredients may result in adverse reactions7. Potential for overdose8. Multiple medication users are at risk as more medications are added to therapy regimen9. Interactions of medications are potentially dangerous

 

1. 3.       Investigational drug

-          new drugs undergoing clinical trails

1. 4.       Illicit/street drug

-          used/distributed illegally for non-medical purposes to alter mood of feeling