Pharmacology 1 - Copy PDF

INTRODUCTION TO PHARMACOLOGY: Dr. HAMAD ALSHABI THE IMPORTANCE OF PHARMACOLOGY FOR DENTIST: A broad knowledge of pharmacology along with focus on particular aspects is needed by the dentist because: 1- Dentists have to prescribe/use drugs for the treatment of dental...

INTRODUCTION TO PHARMACOLOGY: Dr. HAMAD ALSHABI THE IMPORTANCE OF PHARMACOLOGY FOR DENTIST: A broad knowledge of pharmacology along with focus on particular aspects is needed by the dentist because: 1- Dentists have to prescribe/use drugs for the treatment of dental conditions or as adjuvant to dental procedures. 2- Many dental patients could be receiving other medication that may have orodental implications, or may interact with drugs prescribed by the dentist. 3- The dentist may have to deal with a medical emergency arising in the dental office during the course of a procedure. DRUG NOMENCLATURE (Drug names): 1- Chemical Name: It identifies the chemical and molecular composition. It is complicated, not suitable for prescribing e.g. - acetylsalicylic acid for aspirin. Dr. HAMAD ALSHABI 2- Nonproprietary, Generic Name: - is official, Approved name given by an official (pharmacopoeia) agency, e.g. WHO. It is less complicated, internationally identified, and should be used in prescription. each drug has one Generic Name e.g. aspirin, paracetamol. 3- Proprietary, Trade /brand name: - is assigned by the manufacturer - One drug may have multiple proprietary names. e.g. panadol, paramol, Amol for paracetamol. DOSAGE FORMS OF DRUGS Drug substances are seldom administered alone; rather, they are administered as dosage forms. Dosage Form is a formulation that contains the drug (active ingredient) and some inactive ingredients in quantities and physical form suitable for administration of a drug to a patient. Classification of dosage forms: 1- Solid dosage forms For absorption, Solid must disintegrate to release drug then the drug must dissolve into solution. a) Powder: The drug is in a dry and finely divided state that may be intended for internal (oral) or external (topical, such as dentifrices) use. b) Tablets: Tablets contain active drug plus binders, colorants, preservatives, and other substances. The tablet may be plain or coated. - sugar/ film coated: protect the drug and masks its bad taste. - enteric coated (delayed release): in which the coat dissolves in the intestine to avoid gastric irritation or inactivation by gastric acid. c) Capsules: capsules are hard or soft gelatin shells enclosing a powdered or liquid medication. The capsules may be enteric coated. Tablets and capsules may also be formulated to slowly release drugs (controlled- release, extended-release, or sustained-release formulations) and prolong their duration of action. d) Lozenges: Large tablets held in the mouth to dissolve or disintegrate slowly and produce local action. e) Suppositories: for insertion into the anal canal. Dr. HAMAD ALSHABI 2- Liquid dosage forms: a) solution: A clear, homogenous liquid dosage form that contains one or more chemical substances dissolved in a solvent or mixture of miscible solvents. They are used for oral, topical or parenteral administration. solution preparations for internal use: - Syrup: aqueous solution containing a high concentration of sucrose or other sugars. - Elixir: sweetened hydroalcoholic solution of drug. solution preparations for oral topical use: Gargles and Mouth washes. b) Suspensions: are dispersion of insoluble drugs in water with the help of a suspending agent. c) Emulsions: are uniform mixtures of two immiscible liquids (mostly oil and water) in which droplets of one are suspended in the other with the help of an amphiphilic emulsifying agent. Both suspensions and emulsions tend to settle down on keeping; should be shaken thoroughly before use. For absorption of Liquid dosage forms: - Drug in suspension must dissolve into solution. - Drug in solution is already dissolved. - Solutions are generally absorbed more quickly than suspensions. - Solutions and suspensions are generally absorbed more quickly than solid dosage forms because they do not require disintegration. 3- Semisolid dosage forms: a) Ointments: These are greasy semisolid preparations meant for external application. The drug is incorporated in an oily base. Dr. HAMAD ALSHABI b) Pastes: Semisolid but with solid particles at greater concentration when compared to ointment, which produces stiffer or more viscous preparation e.g Toothpastes. c) Gels: Translucent, non-greasy semisolid with higher water or alcohol percent than creams or ointment. Gelling agent is used for their preparation. d) Creams: are similar to ointment but the base is a water in oil emulsion. ROUTES OF DRUG ADMINISTRATION Dr. HAMAD ALSHABI