Sources & Bodily Effects of Drugs Pharmacy Technician Sources & Bodily Effects of Drugs

Key Terms Adverse drug effects Dosage Drug interactions Drug processes Effects of drugs Sources of drugs Variables

DRUG-Any chemical substance taken into the body for the purpose of affecting body function

Sources of drugs Sources of Drugs Plants Animals Minerals Synthetic

Effects of Drugs No matter how different the source, the common characteristic of all drugs is the ability to affect body function in some manner When introduced to the body, all drugs cause cellular change (drug action), followed by physiological change (drug effect) Systemic-reaches widespread areas of the body Local-limited to an area of the body where administered

Drug Processing by the Body Pharmacokinetics 4 DRUG PROCESSES: ADME ABSORPTION-Absorption is the transfer of a drug from its site of administration to the bloodstream. Drugs that are inhaled or injected enter the bloodstream more quickly than drugs taken orally. Oral drugs are absorbed by the stomach or small intestine and then passed through the liver before entering the bloodstream. DISTRIBUTION-Distribution is the transport of a drug from the bloodstream to tissue sites where it will be effective, as well as to sites where the drug may be stored, metabolized, or eliminated from the body. Once a drug reaches its intended destination, the drug molecules move from blood through cellular barriers to various tissues.

ADME Cont’d METABOLISM-While circulating through the body, a drug undergoes chemical changes as it is broken down in a process called metabolism, or biotransformation. Most of these changes occur in the liver, but they can take place in other tissues as well. EXCRETION-Eventually, most drugs or their metabolites circulate through the kidney, where they are discharged, or eliminated, into the urine. Drugs can also be excreted in the body's solid waste products, or evaporated through perspiration or the breath.

Our body recognizes drugs as "foreign substances Our body recognizes drugs as "foreign substances." It removes them, usually in urine or in bowel movements. Many drugs are removed unchanged by the kidneys in urine. Other drugs must be processed by the liver. Enzymes in the liver change drug molecules, and then they are eliminated in urine or in bowel movements. When you take a pill, the drug goes from the stomach into the intestine and then into the liver before circulating to the rest of the body. If the drug is easily broken down by the liver then very little of the drug reaches the body.

Other Variables AGE WEIGHT SEX PSYCHOLOGICAL STATE

DRUG INTERACTIONS SYNERGISM-the action of 2 drugs working together in which 1 helps the other simultaneously for an effect that neither could produce alone Desirable undesirable POTENTIATION-the action of 2 drugs in which 1 prolongs or multiplies the effects of the other drug. ANTAGONISM-the opposing action of 2 drugs in which 1 decreases or cancels out the effect of the other

Dosage Minimum dose-smallest amount that will produce a therapeutic effect Maximum dose-largest amount of a drug that will produce a desired effect Loading dose-initial high dose used to quickly elevate the level of the drug in the body Maintenance dose-dose required to keep the drug level at a steady state Toxic dose-amount of a drug that will produce harmful side effects of symptoms or poisoning Lethal dose-dose that causes death Therapeutic dose-dose that is customarily given (avg adult dose based on body wt of 150 lbs)

Route GI tract routes Parenteral routes Oral Nasogastric tube Rectal Parenteral routes Injection routes IV, IM, SC, ID Intracardiac, intraspinal, intrascapsular Topical Dermal, muscosal Inhalation There are advantages and disadvantages of each route. The doctors choice of a particular route of administration of a drug may depend on 1.) desired effects, 2.) absorption qualities of the drug 3.) how the drug is supplied

Unexpected Responses to Drugs Teratogenic effect-effect from maternal drug administration that causes the development of physical defects in a fetus Idiosyncrasy- Unique, unusual response to a drug Tolerance-decreased response to a drug Dependence-acquired need for a drug that may produce psychological and/or physical symptoms of withdrawl when the drug is discontinued Psychological Physical Hypersensitive-immune response (allergy) to a drug may be of varying degrees Anaphylactic reaction-severe possibly fatal allergic response Medic-Alert tag

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