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Pharma week 3 FUNDAMENTALS CONCEPTS OF PHARMACOLOGY 2nd topic Weight Age Gender Physiological Pathological Genetics Immunological Psychological Environment Tolerance Cumulation Interactions 1.Weight People who are much heavier may require larger doses to get a therapeutic effect from a drug becau...

Pharma week 3 FUNDAMENTALS CONCEPTS OF PHARMACOLOGY 2nd topic Weight Age Gender Physiological Pathological Genetics Immunological Psychological Environment Tolerance Cumulation Interactions 1.Weight People who are much heavier may require larger doses to get a therapeutic effect from a drug because they have increased tissues to perfuse and increased receptor sites in some reactive tissue 2.Age Children metabolize many drugs differently than adults do, and they have immature systems for handling drugs.   Older adults undergo many physical changes that are a part of the aging process. Their bodies may respond very differently in all aspects of pharmacokinetics. 3.Gender  Physiological differences between men and women can influence a drug's effect. When giving IM injections: men have more vascular muscles so the effects of the drug will be seen sooner women have more fat cells than men do so drugs that deposit in fat may be slowly released and cause effects for a prolonged period 4.Physiological Factors Physiological differences such as diurnal rhythm of the nervous and endocrine systems, acid--base balance, hydration, and electrolyte balance can affect the way that a drug works on the body and the way that the body handles the drug. 5.Pathological Factors  Other pathological conditions can change the basic pharmacokinetics of a drug. GI disorders can affect the absorption of many oral drugs Vascular diseases and low BP alter the distribution of a drug Liver or kidney diseases affect the way that a drug is biotransformed and excreted and can lead to toxic reactions 6. Genetic Factors  Some people lack certain enzyme systems necessary for metabolizing a drug, whereas others have overactive enzyme systems that cause drugs to be broken down more quickly.   Predictable differences in the pharmacokinetics and pharmacodynamic effects of drugs can be anticipated with people of particular cultural backgrounds because of their genetic makeup. Pharmacogenomics is a new area of study that explores the unique differences in response to drugs that each individual possesses based on genetic makeup. 7. Immunological Factors  People can develop an allergy to a drug. After exposure to its proteins, a person can develop antibodies to a drug.   With future exposure to the same drug, that person may experience a full-blown allergic reaction. 8. Psychological Factors The patient's attitude about a drug has been shown to have an effect on how that drug works.   A drug is more likely to be effective if the patient thinks it will work than if the patient believes it will not work. This is called the placebo effect.   The patient's personality also influences compliance with the drug regimen. Some people who believe that they can influence their health actively seek health care and willingly follow a prescribed regimen. 9. Environmental Factors Some drug effects are enhanced by a quiet, cool, non-stimulating environment.      Sedating drugs: reducing external stimuli to decrease tension and stimulation help the drug be more effective      Antihypertensives: work well during cold, winter months may become too effective in warmer environments 10. Tolerance The body may develop a tolerance to some drugs over time.   Tolerance may arise because of increased biotransformation of the drug, increased resistance to its effects, or other pharmacokinetic factors.   When tolerance occurs, the drug no long cause Tolerance is a person's diminished response to a drug, which occurs when the drug is used repeatedly and the body adapts to the continued presence of the drug. Resistance refers to the ability of microorganisms or cancer cells to withstand the effects of a drug usually effective against them. (Missed used na gamot)   TYPES OF DRUG RESISTANT TB  TB is treatable and curable. Multidrug-resistant TB (MDR TB) is caused by TB bacteria that is resistant to at least isoniazid and rifampin, the two most potent TB drugs. These drugs are used to treat all persons with TB disease.   Extensively drug-resistant TB (XDR TB) is a rare type of MDR TB that is resistant to isoniazid and rifampin, plus any fluoroquinolone and at least one of three injectable second-line drugs (i.e., amikacin, kanamycin, or capreomycin). 11. Cumulation If a drug is taken in successive doses at intervals that are shorter than recommended, or if the body is unable to eliminate a drug properly, the drug can accumulate in the body, leading to toxic levels and adverse effects. 12. Interactions  When two or more drugs or substances are taken together, there is a possibility that an interaction can occur, causing unanticipated effects in the body.   Alternative therapies, such as herbal products, act as drugs in the body and can cause these same interactions.   Certain foods can interact with drugs in much the same way. Controlled Substances The Controlled Substances Act of 1970 established categories for ranking of the abuse potential of various drugs. The FDA studies the drugs and determines their abuse potential; the DEA enforces their control. Drugs with abuse potential are called controlled substances. DEA Schedules of Controlled Substances Schedule I (C-I): High abuse potential and no accepted medical use (heroin, marijuana, LSD)   Schedule II (C-II): High abuse potential with severe dependence liability (narcotics, amphetamines, and barbiturates)   Schedule III (C-III): Less abuse potential than schedule II drugs and moderate dependence liability (nonbarbiturate sedatives, nonamphetamine stimulants, limited amounts of certain narcotics) Schedule IV (C-IV): Less abuse potential than schedule III and limited dependence liability (some sedatives, antianxiety agents, and non-narcotic analgesics)   Schedule V (C-V): Limited abuse potential. Primarily small amounts of narcotics (codeine) used as antitussives or antidiarrheals.   Orphan Drugs These are drugs that have been discovered but are not financially viable and therefore have not been "adopted" by any drug company. Over-the-Counter Drugs These are products that are available without prescription for self-treatment of a variety of complaints.