For Quality, Essential, Generic Medicines
Chapter 1: About Drugs in General    
 
Efficacy, Safety and Convenience of Dosage Forms
Systemic dosage forms
  Oral   (mixture, syrup, tablet [coated, slow-release], powder, capsule)
  sublingual   (tablet, aerosol)
  rectal   (suppository, rectiol)
  inhalation   (gases, vapour)
  injections   (subcutaneous, intramuscular, intravenous, infusion)
  Local dosage forms
  skin   (ointment, cream, lotion, paste)
  sense organ   (eye drops/ointment, ear drops, nose drops)
  oral/local   (tablets, mixture)
  rectal/local   (suppository, enema)
  vaginal   (tablet, ovule, cream)
  inhalation/local   (aerosol, powder)
  Oral forms
  efficacy :
(-) uncertain absorption and first-pass metabolism, (+) gradual effects (that is a ,
drug may be metabolised before it can be measured in the systemic circulation - one of the causes of low oral bio-availability. For more information see: http://www.merck.com/pubs/mmanual/section22/chapter298/298c.htm ).
     
     
  safety : (-) low peak values, uncertain absorption, gastric irritation
  convenience : (-) handling (children, elderly)
Sublingual tablets and aerosols
  efficacy : (+) act rapidly, no first-pass metabolism
  safety : (-) easy overdose
  convenience : (-) aerosol difficult to handle, (+) tablets easy to use
Rectal preparations
  efficacy : (-) uncertain absorption, (+) no first-pass metabolism, rectal fast effect
  safety : (-) local irritation
  convenience : (+) in case of nausea, vomiting and problems with swallowing
  Inhalation gases and vapours
  efficacy : (+) fast effect
  safety : (-) local irritation
  convenience : (-) need handling by trained staff
  Injections
  efficacy : (+) fast effect, no first-pass metabolism, accurate dosage possible
  safety : (-) overdose possible, sterility maybe a problem
  convenience : (-) painful, need trained staff, more costly than oral forms
  Topical preparations
  efficacy : (+) high concentrations possible, limited systemic penetration
  safety : (-) sensitization in case of antibiotics, (+) few side effects
  convenience : (-) some vaginal forms difficult to handle
  Source: Guide to Good Prescribing, WHO Action Programme on Essential Drugs, Geneva, 1995.

Suppositories are solid bullet-shaped drug forms which can be easily inserted into the rectum; and when these drug forms are available for insertion into the vagina, they are called pessaries. They both contain a drug and an inactive substance which is derived from vegetable oil or cocoa butter. The active ingredients are released slowly as the suppository or pessary dissolves at body temperature.

Drops for eyes, ears and nose are drug solutions administered by means of a dropper.

Nasal Spray contains a solution of a drug in water administered in the nose by means of a dropper or spray.

Inhalers are drugs in solution or suspension form which are then released under pressure. The aerosol inhalers function by means of a valve mechanism which ensures delivery of the recommended dosage. It contains a mouth piece and is used for respiratory conditions.

Evaluation of Drug Profiles

The drug profiles in this book in Section 2 give detailed information on 51 individual drugs. The drugs have been so selected that they cover all the main drug classes which are widely used. When a certain drug-class comprises a number of different drugs, only the ones that are most commonly used have been included in this book.

The drug profiles are aimed at providing information and guidance to the lay person. Information on 107 other drugs has been included in tabular form in Section 3.

Each drug profile is presented in the same way, using standard headings in a uniform sequence. To help the reader understand the information, each heading of the drug profile is explained in detail.

     
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