PEDIATRIC DOSING.pdf

PHARMACOLOGY REYES, DHAYNE H. | DOCTOR OF DENTAL MEDICINE | DEN-221 PEDIATRIC DOSING Infants/ neonate prolonged...

PHARMACOLOGY REYES, DHAYNE H. | DOCTOR OF DENTAL MEDICINE | DEN-221 PEDIATRIC DOSING Infants/ neonate prolonged emptying time. Pediatric – relating to the branch of medicine dealing with children and their diseases. → While some drugs absorbed in the small intestine, the absorption or therapeutic effect -oxford dictionary. may be delayed. CHILDHOOD STAGES: GASTROINTESTINAL ENZYME ACTIVITIES 1. NEONATE – Up to 28 days. -It is lower in new born that in adult activities of -Infant that is 4 weeks old. amylase and lipase, beta-glucuronidase and glutathione peroxidase enzymes are low in 2. INFANTS- Ages 1-24 months infants up to 4 months of age. -A child under the age of 1 yr. ABSORPTION IN INTRAMUSCULAR ROUTE 3. CHILDREN- Ages 2-11 years. Less Predictable absorption in infant -A person between birth and puberty, or Diazepam- rapid absorption- between that developmental period of infancy relieves symptoms of anxiety and puberty. and alcohol (withdrawal) Phenobarbital- poor absorption 4. ADOLESCENTS- Ages 12-18 and are used to control seizures. -A young person who has begun puberty but has ABSORPTION FROM SKIN not become an adult. Percutaneous (skin) absorption may be Remember: Drugs that are effective in one group increased in neonate because of of pediatric patients may be ineffective or toxic in underdevelopment epidermal barrier another group of pediatric patients. (stratum corneum) and increase skin PHARMACOKINETICS in Pediatric hydration. ABSORPTION ABSORPTION FROM RECTAL ROUTE DISTRIBUTION The rectal route of administration (ROA) METABOLISM may be useful to infants or children who EXCRETION are unable to take oral medication. TWO (2) FACTORS AFFECTING ABSORPTION IN suppository GI TRACT of Pediatric PX DISTRIBUTION 1. PH- Dependent passive diffusion. Drug distribution may be determined by: Premature infants- elevated pH (high acidity and high alkaline) Physicochemical properties of the drug: Infants pH 6-8 pKa 2. GASTRIC EMPTYING molecular weight Tests that measure the time it Physiologic factors: takes for food to empty out of o Total Body Water – your stomach. 94% in the fetus, 85% in premature infants, 1|Page PHARMACOLOGY REYES, DHAYNE H. | DOCTOR OF DENTAL MEDICINE | DEN-221 78% in full term infants, ADVERSE DRUG REACTIONS 60% in adults. 1. THERAPEUTIC EFFECT - the action of a drug o Plasma Protein Binding Drug- that is clinical desirable. plasma protein binding may be associated with drug safety 2. ADVERSE EFFECT - the undesirable action of a issues and several adverse drug. effects. o Volume of Distribution (Vd) – 3. TOXIC EFFECT - are adverse effects of an the decrease in plasma protein unexpected nature resulting from the direct binding of drugs can increase action of the drug on the tissue or organ system. their apparent volume of 4. ALLERGIC REACTION - requires the production distribution. of other compounds to elicit a response METABOLISM 5. SIDE EFFECT - are generally predictable, mild Drug metabolism is substantially slower reactions that must be accepted as being in infants compared with other children commonly present when a particular drug is used and adults. 4 GENERAL GROUP OF ACTION OF DRUG Remember: child dose is adjusted in accordance UNDER ADVESE EFFECTS with formulas based on weight or age. 1. Toxic Reactions The ff. formulas have been suggested for dose 2. Allergic Reactions (Drug Hypersensitivity) calculation for: 3. Idiosyncrasies INFANTS AND PRESCHOOL CHILDREN 4. Interference with the natural defense CLARK’s RULE (based on weight) mechanisms Weight (lb) a Adult Dose = Infant Dose 150 CLINICAL MANIFESTATION OF DRUG ADVERSE FRIED’S RULE (based on age) EFFECTS Age in months x Adult Dose = Infant Dose Toxic Reactions may occur as: 150 1. Exaggerated effects on target organs or tissues PRESCHOOL TO ADOLESCENT 2.Effects on nontarget organs or tissues YOUNG’S RULE 3.Effects on fetal development Age in year x Adult Dose = Child Dose Age in years + 12 4.Local reactions COWLING’S RULE 5.Drug interactions Age (at next birthday) x Adult Dose = Child d. 1. EXAGGERATED DRUG EFFECTS ON TARGET 24 ORGANS OR TISSUES considered as an extension of the therapeutic effects produced in a 2|Page PHARMACOLOGY REYES, DHAYNE H. | DOCTOR OF DENTAL MEDICINE | DEN-221 sensitive patient or by an overdose of o induration the drug. o tissue necrosis Consider the following: for TOPICAL ROUTE: o this type of drug reaction may result o irritation from the presence of disease in the o itching patient for ENTERAL ROUTE: o this type of effect may inhibit either drug metabolism or excretion o nausea o effect could prolong the action of drug o vomiting o dyspepsia (constipate) II. EFFECTS ON NONTARGET ORGANS OR TISSUES DRUG INTERACTIONS caused by non-therapeutic action of drug -Defined as an action of an administered drug on usually appears in higher doses or with more the effectiveness or toxicity of another drug prolonged administration administered earlier, simultaneously, or later. a reduction of drug can generally terminate this o Drug enhancement adverse effect o Antagonism CONGENITAL ANOMALIES of body metabolism ALLERGIC REACTIONS may alter patient’s reaction to many drugs (DRUG HYPERSENSITIVITY) preexisting disease may intensify the effect on -Ingested drug must be metabolized to a reactive nontarget organs drug metabolite called HAPTEN -HAPTEN can act as an antigen only after III. EFFECTS ON FETAL DEVELOPMENT combining with high molecular weight (TERATOGENIC EFFECT) compounds in the body called PROTEINS. drug groups in dentistry that carry TYPE OF ALLERGIC REACTIONS IN DRUG ALLERGY warnings about use during pregnancy: 1. TYPE I- o NSAIDS Immediate hypersensitivity reactions o Tetracyclines o mediated by immunoglobulin E o Benzodiazepines (IgE) antibodies (place ** Patient do not always indicate that they are significant role atopic condition pregnant, so it is important to ask them. by inducing immediate hypersensitive reaction, in short LOCAL REACTIONS they release chemical reaction are characterized by tissue irritation that cause allergic reaction) o IgE binds to the mast cells and PARENTERAL Routes of Administration basophils (injectable) can produce the following: o when drug antigen binds with o irritation on site of administration IgE antibody, histamine, o pain 3|Page PHARMACOLOGY REYES, DHAYNE H. | DOCTOR OF DENTAL MEDICINE | DEN-221 leukotrienes, edema, and IDIOSYNCRASY inflammatory response. are reactions that cannot be explained o TARGET of this reactions are the by pharmacologic or biochemical VASCULATURE resulting in: mechanisms ALLERGY ANAPHYLACTIC SHOCK INTERFERENCE WITH NATURAL DEFENSE ANAPHYLAXIS -is an acute, life-threatening MECHANISM allergic reaction characterized by: e.g. long term use of antibiotics hypotension bronchospasm laryngeal edema cardiac arrhythmias -can occur 5 to 30 minutes after drug administration. TYPE OF REACTIONS IN DRUG ALLERGY RESPIRATORY SYSTEM- Rhinitis, asthma SKIN - Urticaria (itchy patches), Dermatitis 2.TYPE II -Reactions are mediated by IgG and IgM antibodies called CYTOLOGIC REACTIONS o When drug antigen binds to these antibodies, the antigen-antibody complex results in cell destruction. 3.TYPE III o known as ARTHUS REACTIONS o mediated by IgG antibody o the drug antigen-antibody complex fixes complement and deposits in the vascular endothelium o results in serum sickness -Urticarial skin eruptions/ -Arthralgia (shrink joints) -Arthritis 4|Page