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Lecture 4.

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Presentation on theme: "Lecture 4."— Presentation transcript:

1 Lecture 4

2 Therapeutic alternatives:
These are drug products that contain different active ingredients but of the same pharmacologic class and used for the same therapeutic objective. e.g.1 Diclofenac-containing drug products could be used instead of those containing Indomethacin or Ibuprufen (as NSAI). e.g.2 Naphazoline hydrochloride and Phenylephrine hydrocholride (as vasoconstrictors).

3 Routes of administration
The majority of drugs must be absorbed into bloodstream in order to reach the site of action. They affect the rate and efficiency of absorption. A particular drug may be available in different forms. Many drugs are available as tablets and injection.

4 The choice between tablets and injection depends on a number of factors including:
The severity of illness. The urgency with which the drug effect is needed The part of the body requiring treatment. The patient’ s general state of health (ability to swallow).

5 Oral administration Advantages:
Is the most frequently used method of administration. Most drugs are absorbed into bloodstream through the walls of the intestine. Advantages: Safe, easy and economic.

6 Disadvantages: Unsuitable in certain medical conditions and for some drugs such as: Emergency due to slow onset of action Presence of nausea, vomiting and diarrhea. Drugs destroyed by gastric acid e.g. Penicillin. Drugs destroyed by GIT enzymes e.g. Insulin. Drugs inactivated by first pass metabolism in the intestinal mucosa e.g. Nitroglycerin. Drugs that interact with food e.g. Tetracycline.

7 Swallowing difficulty:
Unconscious patients Children refuse to swallow oral medications Geriatrics often have difficulty in swallowing

8 Sublingual administration
The drug is inserted under the tongue in the form of tablet. Advantages: Rapid onset of action (less than 5 minutes). Suitable for drugs subjected to first pass mechanism e.g. Nitroglycerine.

9 Disadvantages: Short duration of action (the length of time that a drug gives a therapeutic effect). Unsuitable for irritant drugs and drugs with bitter taste.

10 Parenteral administration
Drugs may be injected into body to produce systemic effect. Advantages: Rapid response. Lower dose and side effects. Person’s intolerance to a drug when taken by mouth (irritant drug). Suitable for drugs destroyed by gastric acid. Suitable for drugs with poor GIT absorption.

11 Disadvantages: Dangerous as it is difficult to remove the drug once it is administrated. Invasive and painful (lower compliance). Sterile techniques are necessary to avoid the risk of infection. Need special experience.

12 Types of injections

13 The type of injection used depend on:
Types of injections: Intravenous (IV) Intramuscular (IM) Subcutaneous (SC) Intradermal (ID) The type of injection used depend on: The nature of drug The condition being treated.

14 Intravenous route Administration and precautions:
Are usually made into a peripheral vein with an angle of 15-20o. A danger for IV rout is the introduction into toxic agents or microorganisms directly into bloodstream. Solution must be sterile and free of particles or air bubbles (embolism).

15 Intramuscular injection
Administration and precautions: Slower onset of action and longer duration (depot effect) compared to IV route. Are given in the upper outer portion of the iliac muscle (avoid nerve insertion). Injection is administered with 90 o angle. Volume of injection up to 5 mL.

16 Subcutaneous injection
Administration and precautions: Longer duration of action compared to IV and IM Is given below the skin into the subcutaneous fat (45o angle). Usually on the outside of the upper arm, may also in the abdomen. No more than 1.5 mL should be injected. Common example is insulin.

17 Intradermal injection
Administration and precautions: Administered into the capillary rich dermis (10-15o angle). Used for local anesthesia. The major use is allergy skin testing.

18 Rectal administration
Drugs are administrated into the rectum in the from of suppositories or retention enema. Advantages: Rapid onset of action. Suitable for drugs destroyed by gastric acid. Drugs subjected to first pass metabolism. Suitable in case of nausea, vomiting and coma. Disadvantages: Irregular absorption.

19 Inhalation Advantages:
Drugs may be inhaled to produce a systemic effect or a local effect on the respiratory tract. Drugs are gases or volatile liquids. Advantages: Rapid onset of action. Can be used for a local effect on the lungs e.g. bronchodilator in asthma and bronchitis. or for a systemic effect e.g. inhalation general anesthetics.

20 Topical administration
The drug is applied to the skin or mucous membranes. Used in treating localized disorders such as skin infections and nasal congestion. Available in a variety of forms such as creams, lotions and eye and ear drops.

21 Advantages: Disadvantages: Slow onset of action.
It is easier to control the effects of drugs applied locally and to produce the maximum benefit with minimum side effects. Disadvantages: Slow onset of action.

22 Slow-release preparations
They are formulated to release their active drug slowly over a given period of time. Used when it is necessary to control the release of small amounts of drug into body. Present in the form of depot injections, transdermal patches, implants, tablets and capsules.

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