Excitement: strengthening or improving the original functional activities of the body's organs; Inhibition: weakening or reducing the original functional activities of the body's organs. Changes in excitability, reactivity, and metabolism

Direct effect (primary effect): The direct effect of a drug on the tissues and organs it comes into contact with. Indirect effect (secondary effect): secondary reaction in other tissues and organs caused by the direct effect of the drug. Local effect: The effect of the drug on the local area before it is attracted into the blood circulation. Absorption (systemic effect): The systemic reaction caused by the drug being absorbed into the blood circulation. Generally also refers to the effect that occurs after a drug is transported to various tissues and organs throughout the body.

Selective effect: The pharmacological effect of a certain drug is limited to specific organs, but has no obvious effect on other organs.

Treatment of causes and symptoms

Side effects: Refers to the effects of a drug at therapeutic doses that are unrelated to the therapeutic purpose. Side effects are adverse reactions. Toxic effects: Damage to the body caused by excessive doses of drugs or long-term use of certain drugs, and even endangering the safety of sick animals. Allergic reaction (anaphylaxis) (has little to do with drug dose, and different drugs can cause similar symptoms. Epinephrine is the drug of choice for anaphylactic shock) Aftereffect: refers to the blood drug concentration that has dropped to the threshold concentration after stopping the drug (effective concentration) below, the remaining pharmacological effects.

Half-effective dose (ED50): The dose that causes a positive reaction or is effective in 50% of the animals in a group of animals. LD50: The dose that causes the death of 50% of the animals in a group of experimental animals.

Dose-response curve

Therapeutic index = LD50/ED50 Safety range: [minimum effective rate, minimum poisoning amount]

Effects on enzymes, effects on ion channels, effects on nucleic acids, effects on neurotransmitters or internal active substances, participation in or interference with cell metabolism, effects on immune mechanisms, changes in physical and chemical conditions

①Oral administration - influencing factors: emptying rate, pH value, filling degree of gastrointestinal contents, drug interactions, first-pass effect ② Injection administration - intravenous injection (no absorption process); intramuscular injection; subcutaneous injection (small dose); intradermal injection (allergy test) ③Respiratory administration-fast absorption; no first-pass effect ④Skin administration (drug concentration and matrix affect absorption) - conditions met by drenching agents: the drug dissolves from the preparation matrix and passes through the stratum corneum and epithelial cells; the drug is fat-soluble

Absorption rate: intravenous injection > alveolar administration > intraperitoneal injection > intramuscular injection > subcutaneous injection > intradermal injection > mucosal administration (oral) > skin administration (smear)

Bioavailability: refers to the speed and degree of drug absorption from the site of administration into the systemic circulation. First-pass effect: The phenomenon in which drugs are absorbed from the gastrointestinal tract and enter the liver through the portal vein system, where they are metabolized for the first time, reducing the amount of drug entering the systemic circulation.

Influencing factors: ① The physical and chemical properties of the drug; ② The concentration gradient between blood and tissue; ③ The blood flow of the tissue; ④ The affinity of the drug to the tissue Storage - bound to plasma proteins Tissue barriers: blood-brain barrier, placental barrier

Phase and type: Phase I reaction - oxidation, reduction, hydrolysis Phase II reaction - binding

How the drug is excreted: Bile excretion, renal and intestinal excretion, milk excretion, pulmonary excretion, salivary excretion.

Reasons for using blood drug concentration to evaluate drug changes in the body: (drawing lines may be considered) ① Target site concentration is generally positively correlated with blood drug concentration and pharmacological effects; ② Changes in blood drug concentration can reflect changes in concentration at the target site; ③Plasma drug concentration can reflect the ADME pattern of the target site; ④ Blood samples are easy to obtain and cause little damage to the body Note: Plasma drug concentration refers to the drug concentration in plasma and is not equal to the target site concentration.

drug time curve

Apparent volume of distribution: When the distribution of a drug in the body reaches dynamic equilibrium, the total volume required for the total amount of drug to be distributed according to blood drug concentration. Vd=A (total amount of drug in the body, mg)/C (plasma drug concentration, mg/L) Elimination half-life: Plasma half-life, the time required for plasma drug concentration to decrease by half. (an important basis for determining the dosing interval) Bioavailability: refers to the speed and degree of drug absorption from the site of administration into the systemic circulation. Area under the drug-time curve—reflects the total amount of drug reaching the systemic circulation

Co-administration and drug interactions Combination medication: Using two or more drugs at the same time to treat a disease is called combination medication. Pharmacokinetic interactions: absorption, distribution, biotransformation, excretion Pharmacodynamic interactions: synergy, antagonism In vitro interactions: incompatibility (when two or more drugs are used together in vitro, they directly cause physical/chemical mutual changes, thereby affecting the efficacy of the drug, and even causing adverse reactions, which are called incompatibility)