Pharmacology Basics

Pharmacology:

The study and description of drugs, their composition, actions, and effects

Pharmacy:A licensed business involved in dispensing drugs.

Dispensing:Compounding, packaging, labeling, and selling and/or delivering a drug in response to a prescription written by a qualified health provider

PharmacokineticsDeals with the effects drugs have on people, including absorption, metabolism, distribution, and excretion

ToxicologyConcerned with the adverse effects of drugs and chemicals used for therapeutic purposes

Clinical PharmacologyStudy of how drugs work, how they interact with other drugs, and their therapeutic effects on diseases and disease processes

Drug:A chemical substance that affects the processes of the mind or body

Any chemical compound used in the diagnosis, treatment, or prevention of disease or other abnormal condition.

Plants◦ From leaves, seeds, sap, stems, fruit, roots

Ex Willow tree extract used in aspirin

Animal Sources◦ Usually a source of hormones

Ex insulin from pigs, estrogen from horses

Minerals◦ Supplements and chemicals

Ex iron, milk of magnesia, lithium carbonate

Semi-synthetic◦ Drug from a natural source is combined with a

synthetically produced compound to alter the effect Ex heroin is semi-synthetic variant of morphine

Synthetic◦ Drug completely formulated in the laboratory

Ex insulin, ibuprofen, diazepam (Valium)

A single drug can have up to four names◦ Chemical

Represents the exact formula Ex N-(4-hydroxyphenyl) acetanamide is Tylenol

◦ Generic Official, nonproprietary name given by international

body to ensure no two products have the same name Always spelled in lowercase

Ex acetaminophen (Tylenol), tetracycline

Trade Name◦ Patented name chosen by a company for sales

purposes Patented compounds are protected for 20 years Patented trade names are protected forever

Other companies can produce a drug after the patent on the compound runs out, but they cannot use the patented trade name

Pharmacists can replace a prescribed Brand name drug with the equivalent generic as long as the doctor has not indicated “no substitutions” Ex Advil (ibuprofen), Tylenol (acetaminophen)

Botanical Name◦ Refers to the natural substance that a drug is

made of Digitalis purpurea is the plant from which digitalis is

derived

Two methods:◦ Prescription

Drugs defined by the federal government to be dangerous, powerful, or habit forming are only available by physician’s order

Correspond to NAPRA Schedule I Pharmacist must have prescription from physician

before it is filled

◦ Over-the-Counter (OTC) Drugs that are considered safe to take without

specific advice of a physician

3 categories Pharmacy Only: Restricted Access (Schedule II) Pharmacy Only: Under Supervision (Schedule III) Sold Anywhere: No Restrictions (Unscheduled)

Classification of Drugs by Use◦ Therapeutic

Taken to relieve symptoms

◦ Diagnostic Used to perform diagnostic tests

◦ Curative Overcome a disease, infection, or other condition

◦ Replacement Taken to replace a hormone or other normally present

substance that the human body can no longer produce

◦ Prophylactic Prevent a condition or to decrease the severity of a

condition

Classification by Scope of Action◦ Local

Drug is stored and produces an effect only at the site of application Ex steroid creams to treat a rash

◦ Systemic Drug circulates through the bloodstream to produce a

general effect Ex most orally ingested drugs

◦ Cumulative Drug accumulates in the body faster than it can be

metabolized or excreted and exerts a greater effect than the initial dose.

Can be harmful or beneficial Ex some antibiotics

Classification by Action or Function

◦ Analgesic◦ Anesthetic (Local, Regional, General)◦ Antacid◦ Anxiolytic◦ Antibiotic (bactericidal, bacteriostatic)◦ Anticoagulant◦ Anticonvulsant

◦ Anti-depressant◦ Antihyperglycemic◦ Antidiarrheal◦ Anti-emetic◦ Antifungal◦ Antihistamine◦ Antihypertensive◦ Anti-inflammatory (NSAID)

◦ Antipyretic◦ Antitussive◦ Bronchodilator◦ Cathartic◦ Contraceptive◦ Decongestant◦ Diuretic◦ Emetic

◦ Hormone◦ Hypnotic◦ Miotic◦ Narcotic◦ Purgative

Classification by route of transmission◦ Some drugs must be administered in a very

specific form for them to act. Others come in different forms that can be used for different circumstances. Ex Antibiotics can be given orally for normal

treatment, but can also be injected intravenously for more rapid action

Topical / Transdermal◦ Applied to a body surface or mucous membrane◦ May be local or systemic

Ex steroid cream to locally treat dermatitis, patch to deliver hormones, heart medication, motion sickness, etc

◦ Ointment: emulsion of semisolid consistency having a petroleum or paraffin base

◦ Lotion: active ingredients contained in a water base

◦ Liniment: active ingredients contained in a liquid base, usually more oil than lotions

Inhalation◦ Drugs administered into the airway to be

absorbed through the mucous membranes of the respiratory system

◦ Puffers or Metered Dose Inhalers (MDI’s) dispense a powder or nebulized liquid

Otic ◦ Placed directly in the ear – usually drops◦ Often antibiotics used to treat ear infection

Ophthalmic◦ Drops or ointments placed directly in the eye ◦ Used to treat localized eye conditions

Nasal ◦ Drugs sprayed or inhaled through the nostrils◦ Sprays are often used for localized effect

Ex Otrivin◦ Mostly decongestants, but also pain medication

Sublingual or Buccal◦ Drugs placed under the tongue or between the

cheek and the gum◦ Usually absorbed through mucous membranes –

no swallowing◦ Quick acting◦ Used for nitroglycerine, Ativan (tranquilizer)

Vaginal◦ Suppositories or creams to treat local infections◦ Creams or foams used in contraception

Rectal◦ Suppositories that dissolve at normal body

temperature◦ Effect can be local or systemic

Ex suppository for hemorrhoids, nausea

◦ Enemas used for diagnostic purposes

Oral◦ Most common route of delivery

◦ Comes in many forms Pills: pressed, round, solid medication (AKA Tablet) Enteric-coated: covered to prevent medication from

dissolving until later in the GI tract (intestines) Sustained Release: additives slow the action of the

drug to ensure sustained action

Oral con’t Caplets: Oval-shaped solid medication, may be

easier to swallow Capsules: drug in powder or liquid form encased in a

hard or soft shell (usually gelatin) – masks taste of drug, can be extended release

Liquid: easy to ingest Suspension: small particles of medicine suspended in a

liquid base Emulsion: droplets of oil and water mixed together Elixir: contains alcohol, sugar water and sometimes

flavouring Syrup: Similar to elixir, but no alcohol and thicker

Parenteral◦ Administration by injection◦ Fastest, most accurate effect◦ Several ways to inject

Subcutaneous (SC) Intradermal Intramuscular (IM) Z-track Intravenous (IV)

Therapeutic Action◦ The effect considered desirable

Side Effect◦ Two kinds:

Those that are expected to occur and are usually minor Those that are detrimental to the health of the patient

(may be fatal) AKA Adverse Effects

Allergies◦ Different from side effects

Serious reaction such as chest pain, skin rash, anaphylaxis that is life threatening

Must also be aware of food allergies when prescribing medication

Body Weight◦ Drug effects are often not about

amount, but about proportion◦ Larger people need larger doses

Age◦ The elderly and young children

process drugs differently due to differences in metabolism and excretion mechanism

Time of Day◦ Food intake, normal body rhythms,

level of activity all affect drug action◦ Some drugs need to be taken on a

strict schedule◦ Some drugs should always be given

at same time of day, some on a full stomach, some on an empty stomach

◦ Certain foods should be avoided with certain drugs

Gender◦ Men and women’s bodies process differently

due to differences in muscle mass and hormone levels

◦ Pregnancy is also a significant issue

Other medication◦ Physicians and pharmacists check for drug –

drug interactions◦ Herbal medicines can also effect a drug’s action

Includes:◦ Vitamins and Minerals◦ Herbal remedies◦ Homeopathic medicines (HM) and Traditional

medicines◦ Probiotics

Natural Health Products Regulations (2004)◦ To be sold, products must have a Product License

NPN – natural product number DIN-HM – homeopathic medicine number

◦ Manufacturers must have a Site License

Should be treated as drugs◦ Many have therapeutic effects◦ Many also have side, unpredictable and/or

adverse effects◦ Can interact with other, prescribed medications

Encourage patients to bring/list natural health products when they tell the physician about other medications they are taking

Compendium of Pharmaceuticals and Specialties (CPS)◦ Updated list of drugs, with information on action,

indications, contraindications, and side effects

Internet◦ Be careful that you get information from

reputable sources!