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

Plantse.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)morphinecodeine

Atropa Belladonna(Deadly nightshade)Atropine

Digitalis lanata Digitalis purpurea

Cinchona treeQuinine

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

Ricinus communis(Castor been)

Ginkgo biloba (maidenhair tree) FlavonoidsDiterpene lactones

Natural drugs

Microorganismse.g. Penicillin from Penicillium notatum. Streptomycin from Streptomyces griseus. Gentamicin from Micromonospora purpurea. Vancomycin from Streptococcus orientalis.Mineralse.g. Calcium, Magnesium, Aluminium salts. Liquid paraffin from petroleum.

Natural drugsAnimalse.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, SulfadioxineFluoroquinolones – e.g. Ciprofloxacin, Levofloxacin, MoxifloxacinSalicylates – e.g. Acetylsalicylic acidBarbiturates – e.g. PhenobarbitalBenzodiazepines – e.g. Diazepam, Bromazepam, LorazepamAcetaminophen (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 insulinsHuman 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 replaceor supplement defective genes. It imparts new function to cells.CancersAlzheimer’s diseaseParkinson’s disease Diabetes mellitusArterial HypertensionCystic fibrosisMultiple sclerosisMuscular 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.)

Drug nomenclatureChemical name which is LONG, COMPLEX AND NOT USED CURRENTLYNonproprietary 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: OmeprazoleBrand names: Losec (AstraZeneca), Sopral (Sopharma), Probitor (Sandoz), Omeprazid (Nobel Pharma),Ulcoprol (Actavis), Helicid (Zentiva)

1,3 dimethylxanthineNonproprietary name : TheophyllineТrade 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 HealthInsurance Fund.

Structure of the prescription

The prescription consists of seven parts including

1. Inscriptio 2. Praepositio3. Praescriptio 4. Subscriptio5. Signatura6. Nomen medici7. 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

1,0 0,10,010,0010,0001

1 g 100 mg10 mg1 mg100 g

The strength of the drug should be written in metric units.

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. orDa tales doses №20 in tabulettis or short form D. t. d. №20 in tab.

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 formS. Take one tablet 3 times daily.

Nomen mediciSignature and seal of the doctor may be put at the marked place in the prescription blank or after the last prescribed drug.

Nomen aegrotiThis 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 drugse.g.Rp/ Paracetamoli 500 mg D. sat. № 1 in tab. S. Take 1 tablet 3 times daily. #Rp/ Amoxicillini 1 g D. sat. № 1 in tab. 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 thewhole 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.