Prescription and Drug Prescription Writing. Department of Pharmacology & Toxicology Medical University – Sofia Dr Rumen Nikolov, PhD Introduction to Pharmacology. Prescription and Drug Prescription Writing.

Etymologically, pharmacology is the science of drugs (Greek pharmakon, medicine or drug; and logos, study)   Pharmacology is a branch of medicine which deals with drugs. Pharmacology can be defined as the study of the selective biologic activity of drugs in living matter.

A drug is a chemical substance that affects processes in living organism and used for treatment, prophylaxis (prevention) or diagnosis of the diseases. Classification of drugs: OTC (Over-the-counter) drugs - drugs that do not require a prescription. Prescription drugs - prescription drugs generally have a greater potential for adverse effects than OTC drugs, require monitoring for interactions with other medications, should only be used for a restricted time period.

Sources of drugs Natural – plants, microorganisms, animals, minerals. Synthetic Semi-synthetic Biosynthetic

Natural drugs Plants e.g. Morphine from Poppy capsules. Atropine from Belladonna roots. Digoxine from Digitalis leafs. Quinine from Cinchona bark. Hypericin and hyperforin from Hypericum herb. Flavone glycosides and terpenoids from Gingko leafs. Castor oil from Castor seeds.

Papaver somniferum (Opium Poppy) morphine codeine

Atropa Belladonna (Deadly nightshade) Atropine

Digitalis lanata Digitalis purpurea

Cinchona tree Quinine

Hypericum perforatum (St. John’s wort) Esbericum caps. Remotiv tab.

Ricinus communis (Castor been)

Ginkgo biloba (maidenhair tree) Flavonoids Diterpene lactones

Natural drugs Microorganisms e.g. Penicillin from Penicillium notatum. Streptomycin from Streptomyces griseus. Gentamicin from Micromonospora purpurea. Vancomycin from Streptococcus orientalis. Minerals e.g. Calcium, Magnesium, Aluminium salts. Liquid paraffin from petroleum.

Natural drugs Animals e.g. Thyroxine from porcine or bovine thyroid gland. Heparin from porcine gut or bovine lung. Insulin from porcine or bovine pancreas. Omega-3 fatty acids from fish oil (Omacor).

Synthetic drugs (60-65%) - They are prepared by chemical synthesis. Sulfonamides – e.g. Sulfamethoxazole, Sulfadioxine Fluoroquinolones – e.g. Ciprofloxacin, Levofloxacin, Moxifloxacin Salicylates – e.g. Acetylsalicylic acid Barbiturates – e.g. Phenobarbital Benzodiazepines – e.g. Diazepam, Bromazepam, Lorazepam Acetaminophen (Paracetamol) Isoniazid

Semi-synthetic drugs They are prepared by chemical modification of natural drugs. Ampicillin from Penicillin G Dihydroergotamine from Ergotamine Dehydroemetine from Emetine

Biosynthetic drugs These drugs are prepared by cloning of human DNA into bacteria like E. coli. Technique is called Recombinant DNA technology or Genetic engineering. Human insulins Human Growth Hormones (Somatropin) Human Interferons (alpha and beta) Human tissue plasminogen activator (Alteplase, Reteplase) Human Erythropoietin (Eprex)

Gene therapy - It is the introduction of functional genetic material DNA into target cells top replace or supplement defective genes. It imparts new function to cells. Cancers Alzheimer’s disease Parkinson’s disease Diabetes mellitus Arterial Hypertension Cystic fibrosis Multiple sclerosis Muscular dystrophy

Pharmacopoeia An official book published by authorized institution in a country containing description of commonly used drugs with their sources, properties, uses, doses, purity and potency. Drugs contained in pharmacopoeia are official drugs. European pharmacopoeia (E.P.) British pharmacopoeia (B.P.) United States pharmacopoeia (U.S.P.) Indian pharmacopoeia (I.P.)

Chemical name which is LONG, COMPLEX AND NOT USED CURRENTLY Drug nomenclature Chemical name which is LONG, COMPLEX AND NOT USED CURRENTLY Nonproprietary name (some times called ”generic name”) – given by WHO official names (in pharmacopoeias) approved names (not yet in pharmacopoeias) Proprietary name (trade or brand name) - given by the manufacturer e.g. Nonproprietary name: Omeprazole Brand names: Losec (AstraZeneca), Sopral (Sopharma), Probitor (Sandoz), Omeprazid (Nobel Pharma), Ulcoprol (Actavis), Helicid (Zentiva)

1,3 dimethylxanthine Nonproprietary name : Theophylline Тrade name: Novphyllin

Prescription The prescription is a written order from a doctor to a chemist including instructions for dispensing or preparing medicines to a certain patient. It is require that the prescriptions in Bulgaria should be in Latin. The prescription order may be issued by physicians or other licensed medical practitioners and dentists.

Type of prescription forms White Prescription form Yellow Prescription form Green Prescription form Prescription form №5

Doctors use a white prescription form to prescribed drugs without abuse potential.

Doctors use a yellow form to prescribed drugs with high abuse potential such as opioids (e.g. morphine, methadone, fentanyl, pethidine).

Doctors use a green form to prescribed drugs with low abuse potential than opioids such as benzodiazepines (e.g. Diazepam), and barbiturates (e.g. Phenobarbital)

Doctors use a prescription form №5 to prescribed drugs, which are fully or partially paid by the National Health Insurance Fund.

Structure of the prescription The prescription consists of seven parts including 1. Inscriptio 2. Praepositio 3. Praescriptio 4. Subscriptio 5. Signatura 6. Nomen medici 7. Nomen aegroti

Inscriptio This part consists identification data such as name of the doctor, master degree of the doctor, address, and the date. e.g. Dr. I. Ivanov, dermatologist “Alexandrovska” Hospital Sofia, 16.09.2010

Praepositio This part includes message to the pharmacist which express with Rp. or Rp/, an abbreviation for Latin word Recipe (Take thou). Rp. or Rp/ Doctor must write new Rp. for each new prescription

Praescriptio Rp/……… … Name (Genetivus case) Dose

The strength of the drug should be written in metric units. 1,0 0,1 0,01 0,001 0,0001 1 g 100 mg 10 mg 1 mg

Subscriptio This part is intended direction to the pharmacist. Doctor writes the number of the drug packing and the drug dosage form. e.g. Da scatulam №2 in tabulettis or short form D. scat. №2 in tab. or Da tales doses №20 in tabulettis D. t. d. №20 in tab.

Signa. Take one tablet 3 times daily. or short form Signatura (Label) This part is intended direction to the patient. It provides instructions for the manner of the use of the prescribed drug (how the drug should be taken by the patient). e.g. Signa. Take one tablet 3 times daily. or short form S. Take one tablet 3 times daily.

Nomen medici Signature and seal of the doctor may be put at the marked place in the prescription blank or after the last prescribed drug. Nomen aegroti This part of the prescription includes name, home address, and age of the patient.

Symbols and abbreviations used in the prescription  symbol for divided one prescription from next prescribed drugs e.g. Rp/ Paracetamoli 500 mg D. sat. № 1 in tab. S. Take 1 tablet 3 times daily. # Rp/ Amoxicillini 1 g S. Take 1 tablet every 8 h.

Symbols and abbreviations used in the prescription aa (ana partes aequales) is used to expressing substances in equal quantities ad is used to expressing add to get the whole weight (volume) of the solution or “up to” q.s. (quantum satis) means sufficient quantity. M.D.S. means Mix, give and label. M.f. (Misce fiat) means Mix to obtain. Verte! is used when doctor writes on the back of the prescription blank.