Question | Answer |
Solid Drug | Powder
Tablet
Pill
Bolus
Pessary
Suppository |
Liquid Drug | Mixture
Tincture
Spirit
Suspension
Elixir
Emulsion
Extract
Infusion
Decoction
Injection
Liniment
Lotion |
Semisolid Drug | Ointment
Cream
Paste
Electurary |
Gases Or Vapor Drugs | Aerosol
Spray
Mist |
Powder | A mixture of drugs packaged in packets or sachets |
Tablet | Active drugs combined with a binder and excipient.
The mixture is compressed into tablets by machine.
Disk like shape.
Can be scored or unscored. |
Enteric-Coated Tablets | Irritant tablets or which are destroyed by gastric acid are coated with phenylsalicylate (salol) or other substance, which is insoluble in acid, but will dissolve in the alkaline small intestine. |
Pill | Consists of a mixture of drugs & a sticky binder in the form of ovoid or spherical mass, which is provided with a glazed sugar coating. |
Capsule | Is a container made of mixture of gelatin and glycerin and is suitable for drugs in powdered form and certain liquid drugs. |
Bolus | A large and cylindrical in shape.
It is used for horses & cattle. |
Mixture | An aqueous solution or suspension intended for oral administration.
Aromatic water (aqueous solution of a volatile oil such as peppermint or cinnamon) is added to prevent contamination with bacteria or mold. |
Pessary | Conical solid preparation for intravaginal use in humans. |
Suppository | Conical solid preparation given intrarectally for systemic effect in humans.
It melts and releases its active ingredients after being introduced into the body. |
Paste | Semisolid preparation for either external use (on the skin) or internal use. |
Electurary | Semisolid preparation which is applied on the back of the tongue for a systemic effect. |
Tincture | Alcoholic liquid preparation of nonvolatile substance either for external or internal use. |
Spirit | Alcoholic liquid preparation of a volatile substance. |
Suspension | Aqueous suspension of solids & usually contains a dispersing agent (gum tragacanth or methyl cellulose) to delay settling.
The bottle should contain the phrase 'shake well before use'.
Insoluble solid in liquid, usually separates. |
Syrup | Solution of medicinal agents, flavoring and coloring agents in an 85% sucrose solution (more than 50% sucrose). |
Elixir | Hydro-alcoholic solution of medicinal agents that have been sweetened and flavored (it has a better keeping quality than a mixture because of high alcohol content). |
Emulsion | Consists of an oily substance dispersed in an aqueous medium with an emulsifying or a dispersing agent (gum acacia, lecithin or methyl-cellulose).
Consists of two immersible liquids. |
Extract | Obtained by passing the solvent over the dried plant material (percolation) then evaporation of the solvent, or placing the crude material in the solvent until the active substances are extracted (maceration). |
Infusion Extract | When cold water or warm water is used in an extract. |
Decoction Extract | If boiling water is used in an extract. |
Injections | Sterile solutions or suspensions in aqueous (sometimes and oil vehicle).
Heat sterilized or if unstable to heat are filtered through Millipore filters.
Some drugs are unstable in solution and are packaged aseptically in vials. |
Injections | Reconstituted with sterile H2O immediately before injection.
Tablets for injections are somewhat similar to powder in vials. |
Repository Forms (Slow Release Form) | Sustained release forms prolong effective drug concentration in the body by providing for sustained release from the dosage form. |
External Dosage Forms (Red Label) | Liniment
Lotion
Ointment
Cream
Dusting Powder |
Liniment | A liquid or semisolid preparation to be applied on the skin with friction (rubbing).
Generally contains counterirritants used in chronic inflammation of muscles and tendons. |
Lotion | Solution or suspension of soothing substances to be applied on the skin in acute inflammation to relieve pain. |
Ointment | Semisolid greasy preparation in which the drug is dissolved or dispensed in a suitable base. |
Cream | Incorporates a drug in water-oil emulsion.
Water will evaporate following application, leaving the drug and a thin film of oil on the skin. |
Dusting Powder | Mixture of drugs in powder form for external use such as talc or starch as adsorbents. |
Gases Or Vapors | Aerosol |
Aerosol | Drug incorporated in a suitable solvent and packaged under pressure with a propellant such as fluorinated hydrocarbon or nitrogen. |
Vehicles (Solvents Or Carriers) | Solids
Oral Medications
Injections
Semisolid |
Solid Forms Of Vehicles | Starch
Sucrose
Talc
Polyvinylpyrrolidone (PVP)
Resin |
Oral Medications Of Vehicles | Waters (Peppermint Water)
Syrup
Elixir |
Injections Of Vehicles | Sterile Water
Sterile Saline
Propylene Glycol
Polyethylene Glycol
Polyvinylpyrrolidone
Polysorbate 80 (Tween 80) |
Semisolid Forms Of Vehicles | Paraffin Oil & Wax
Bees Wax
Vaseline |
Factors Affecting Selection Of The Route Of Administration | Therapeutic Factors
Drug Factors |
Therapeutic Factors | Onset & duration of action
Site of action
Adverse reactions |
Drug Factors | Irritation
Solubility
pH |
Routes Of Administration | Local
Systemic |
Local Routes Of Administration | Skin
Nasal
Conjunctival
Urethral & Bladder
Vaginal
Rectal
Mammary
Sublingual
GI Tract
Otic
Epidural
Intraspinal
Intrasynovial (Intra-Articular)
Intramedullary (Into Bone Marrow) |
Systemic Routes Of Administration | Oral (Per Os, Enteral)
Parenteral or by injection (Intravenous, IV; Subcutaneous, SQ; Intramuscular, IM; Intraperitoneal, IP)
Inhalation (gases, vapors, aerosol) |
Advantages To Oral Administration | Safe
Convenient in some animals
Economical
No problem of infection |
Disadvantages To Oral Administration | Inactivation of some drugs by gastric acidity, digestive enzymes or rumen microflora
The presence of food may affect absorption
The presence of drug may affect absorption
Activity of the GI tract affects absorption |
Disadvantages To Oral Administration | Irritant drugs may cause vomiting and diarrhea
Onset of action is slow
Unpalatability of some drugs |
Advantages To Intravenous Administration | Accurate
Fast onset of action
Irritating, hypertonic, acidic or basic drugs can be given
Large volumes can be given |
Disadvantages to Intravenous Administration | Dangerous |
Advantages To Intramuscular Administration | Rapid absorption
Duration of action is longer than intravenous
Suspensions can be injected |
Disadvantages To Intramuscular Administration | Irritant, hypertonic, acidic or basic drugs may cause tissue damage |
Advantages To Subcutaneous Administration | Slow absorption but constant
Longer duration of action |
Disadvantages To Subcutaneous Administration | Slow onset
Irritating drugs can not be used |
Metrology | The study of weights & measures used in prescription writing.
Preferable to use the metric system, but the apothecary system is sometimes used. |
Metric System Weights | 1kg = 1000g
1g = 1000mg
1mg = 1000ug
1ug = 1000ng |
Metric System Volumes | 1L = 1000mL
1mL = 1000uL |
The Apothecaries' System Weights | 1 ounce = 8 drams
1 dram = 60 grains
1 grain = 65mg |
The Apothecaries' System Volume | 1 pint = 16 fluid ounces
1 fluid ounce = 8 fluid drams
1 fluid dram = 60 minims |
Approximate Common Conversions | 1 gallon = 4 liters
1 liter = 1 quart = 2 pints
1 kilogram = 2.2 pounds
1 ounce = 30 grams
1 fluid ounce = 20 millimeters
1 grain = 65 milligrams
1mL = 1cc |
Posology | The study of doses |
Dose | The amount of drug given to an animal to give a certain effect |
Dosage | The amount of drug per the unit body weight (kilogram or pound) & is usually in mg/kg or mg/lb |
Types Of Doses | Therapeutic (Effective) Dose
Toxic Dose
Lethal Dose |
Minimal Therapeutic Dose | Smallest amount that has a therapeutic effect |
Maximal Therapeutic Dose | Largest amount that can be tolerated without producing toxic effects |
Therapeutic Dose | Optimal dose, which lies some place between the minimal and maximal therapeutic dose |
The Effective Dose Fifty (ED50) | Effective dose in 50% of the animals
Median effective dose |
The Toxic Dose | Amount that produces undesirable clinical, hematological, biochemical or pathological alterations |
The Lethal Dose | Dose that causes death |
The Lethal Dose 50 (LD50) | Dose that causes death in 50% of the animals
Median lethal dose |
Evaluation Of Relative Safety Of Drugs | The therapeutic index
The standard safety margin |
The Therapeutic Index | Ratio between the LD50/ED50
The larger the therapeutic index, the wider the margin of safety of a drug |
The Standard Safety Margin (SSM 100%) | Expresses the precentage dose increase between ED99 and LD1
LD1/ED99 is called the certain safety factor
The wider the margin between ED99 and LD1 for a drug, the safer the drug
The standard safety margin is more accurate than the therapeutic index |
Abbreviations | Names of drugs should not be abbreviated.
Chemical formulas must not be used in prescription writing.
Abbreviations of Latin words are commonly used in prescription writing because they may save time and are readily understood by the pharmacist. |