Chapter 5

1. Chapter 5 Dosage Forms and Routes of Administration

2. Overview Drug sources Medication errors Dosage forms of drugs Principles of drug administration Methods of administering medications

3. Drug Sources Five basic sources of drugs: Plants Animals (including humans) Minerals or mineral products Synthetic chemicals Bio- or genetically engineered drugs

4. Examples of Drugs and Their Sources Digitalis ― from the foxglove plant Table salt, iron, potassium, silver, gold ― from earth and soil sources Pancreatin, pepsin, thyroid hormone, insulin — from animal fluids, glands, and enzymes (continues)

5. Examples of Drugs and Their Sources Meperidine, sulfonamides, oral contraceptives — synthetically made from artificial substances Newer forms of insulin — from gene splicing or genetic engineering

6. Dosage Form of Drugs Drug dosage forms are classified according to their physical state and chemical composition They may include gases, liquids, solids, and semisolids Some substances can change from one state to another, such as solids to liquids (melting), or liquids to gaseous states (vaporization)

7. Solid Drugs Tablets — may be chewable, sublingual, enteric-coated, or buffered Plasters — compositions of liquid and powder that harden when they dry

8. Solid Drugs Capsules — drug is contained in an external shell, usually gelatin; used when medications have unpleasant odor or taste Sustained-release (SR) or timed-release capsules — released slowly, over a period of time Caplets — shaped like capsules but consisting of tablets that are film-coated to make swallowing easier

9. Solid Drugs Gelcaps — oil-based medications enclosed in soft gelatin capsules Powders — drugs dried and ground into fine particles Granules — small particles encased in a gelatin capsule Troches/lozenges — flattened disks containing medications intended for localized mouth or throat application

10. Solid Dosage Forms

11. Semisolid Drugs Suppositories — bullet-shaped dosage forms inserted into a body orifice (rectum, vagina, and urethra are most common) Ointments — greasy medications for external application; usually rubbed into the skin (continues)

12. Semisolid Drugs Creams — nongreasy preparations with a water base, applied to the skin or administered via an applicator (such as with intravaginal creams) Gels — jelly-like substances for topical application Lotions – preparations applied to the skin to treat dermatologic disorders (continues)

13. Semisolid Drugs Pastes – topical formulations with a fatty base ingredient Patches – method of delivery for some semisolid dosages forms

14. Liquid Drugs Syrups — consist of a high concentration of sugar in water, which may or may not have medicinal substances added Solutions — drugs dissolved in a solvent, such as normal saline Spirits — alcohol-containing liquids used as solvents; also called essences (continues)

15. Liquid Drugs Elixirs — consist of water, alcohol, and sugar Tinctures — alcoholic preparations of soluble drugs Fluidextracts — concentrated solutions of a drug removed from plant sources Liniments — mixtures of drugs with oil, soap, water, or alcohol (continues)

16. Liquid Drugs Mixtures and suspensions — agents mixed with a liquid but not dissolved; must be shaken before use Aromatic waters — mixtures of distilled water with an aromatic volatile oil Emulsions — pharmaceutical preparations of two agents that are not ordinarily mixed, such as oil inside water; most creams and lotions are emulsions

17. Liquid Dosage Forms

18. Sprays and Aerosols Liquids or fine powders sprayed in a fine mist Respiratory treatment for asthma and skin sprays are most common Most are liquids, but some are powders with very small particles that pass through the spray apparatus

19. Gaseous Drugs Include anesthetic gases and compressed gases

20. Principles of Drug Administration Determining factors for route: Action of medication on the body Physical and emotional state of the patient Characteristics of the drug Other factors include: Age of patient Disease and condition of patient Absorption, distribution, metabolism, and elimination of drugs

21. Oral Route Safest and most convenient route Presence or absence of food in the stomach affects the absorption rate Oral drugs are usually not used when the patient is nauseated or vomiting (continues)

22. Oral Route Basic equipment needed for administration: Medicine cup Water cup Medicine dropper/oral syringe Calibrated spoon Sublingual — used when rapid action is desired, such as with migraine and angina medications Buccal — placed between cheek and gum

23. Tools for Administration of Liquid Dosages

24. Sublingual Administration

25. Parenteral Route Administration of drugs other than through the digestive system is called parenteral because the drugs bypass the GI tract Basic equipment needed for parenteral administration includes: Needles Syringes Ampules or vials Solutions, powders, and others

26. Needles Two types available: disposable (most common) and nondisposable Needle gauge is determined by the diameter of the lumen or opening at the beveled tip Range from 13 to 31 in gauge size, with lengths between 3/8 inch and 2 inches The larger the gauge, the smaller the diameter of its lumen (continues)

27. Needles Needles consist of 3 parts: Hub Shaft Bevel

28. Parts of a Syringe

29. Syringes Disposable syringes are sterilized, prepackaged, nontoxic, nonpyrogenic, and ready for use Syringe sizes range from 0.5 to 50 cc Most frequently used sizes are 1, 3, and 5 cc syringes

30. Types of Syringes Hypodermic — typically used for intramuscular or subcutaneous injections Retractable needle cover — used to prevent needle sticks; includes the injector pen used for insulin administration Insulin — calibrated in units (U) specifically for diabetes use; sizes are 0.3, 0.5, and 1 cc (continues)

31. Types of Syringes Tuberculin — used for small injections made intradermally; also used in allergy testing Prefilled — come with a single dose of medication already inside; for one-time use

32. Medication Containers Ampules — small sealed glass containers usually holding a single dose Vials — small bottles with rubber stoppers through which a sterile needle is inserted for the withdrawal of a dose of medication; some are for multiple uses

33. Ampules and Vials

34. Parenteral Medication Forms Parenteral refers to injection of liquid substances into the body via a sterile needle and sterile syringe Can be liquid or powder (reconstituted to a liquid)

35. Parenteral Routes Muscles (intramuscular) Veins (intravenous) Skin (intradermal or subcutaneous) Spinal column (epidural)

36. Intradermal (ID) Injections Given within the skin If correctly done, a small wheal occurs on the skin A three-eighths inch, 27- or 28-gauge needle is used Angle of insertion is 15 degrees, almost parallel to the skin surface (continues)

37. Intradermal (ID) Injections Common site of injection is the forearm Upper chest and back are also used Skin tests for allergies and tuberculosis are commonly done with this method Mantoux test is the preferred test for tuberculosis

38. Intradermal Injection

39. Subcutaneous (SC) Injections Given just below the skin in layer of fatty tissue called adipose tissue Commonly given in deltoid, anterior thigh, abdomen, and upper back Angle of insertion is 45 degrees, except for insulin and heparin, which are at 90 degrees Amount of drug should not exceed 2 mL

40. Subcutaneous Injection

41. Intramuscular (IM) Injections Preferred sites are the gluteus, deltoid, and vastus lateralis (thigh) muscles in adults Used for drugs that require more rapid absorption or large volumes of medication The vastus lateralis is usually used in infants Angle of insertion is 90 degrees Dosage may be from 0.5 to 5 mL (continues)

42. Intramuscular (IM) Injections Infants and children should be given no more than 2 mL Needle should be 1 to 3 inches in length, and even longer for obese patients Recommended gauge ranges from 20 to 23

43. Intramuscular Injection

44. Z-Track Intramuscular Injections Used when the drug is irritating to skin tissue Displaces upper tissue laterally before the needle is inserted Injection site should not be massaged after injection

45. Intravenous (IV) Injections Used during emergency situations Rate of absorption and onset of action are faster with this method than with other routes Usually inserted into superficial veins

46. Pump Systems Pumps provide continuous flow into the system Are electronic devices that force precisely measured amounts of fluid into veins over time Often used for diabetic patients

47. Topical Route Applied to body surface Most topical drugs are designed for local use Examples of topical medications are: Lotions Liniments Ointments Transdermal patches

48. Transdermal Patches Absorbed slowly through the skin Drug is carried from skin by capillaries Examples include: Nitroglycerin Estrogen Testosterone Nicotine Scopolamine

49. Inhalation Administration The act of drawing breath, vapor, or gas into the lungs is called inhalation Medication is inhaled to achieve local effects within the respiratory tract Oxygen therapy is ordered as liters per minute (LPM), with a percentage of oxygen concentration (continues)

50. Inhalation Administration Medications that utilize inhalers include: Bronchodilators Mucolytic agents Steroids (continues)