ROUTE OF DRUG ADMINISTRATION ( Part 3/3 )

3) Tropical Route Of Drug Administration :

Dermal route

Transdermal Route

• Topical application is used when a local effect of the drug is desired.
• For example, clotrimazole is applied as a cream directly to the skin in the treatment of dermatophytosis.
• Topical administration is the application of a drug directly,
• To the surface of the skin
• Dermal- rubbing in of oil or ointment (local action)
• Transdermal - absorption of drug through skin (systemic action) 
•  
• To the mucous membrane i.e. Eye, vagina, nose, urethra, ears, colon, lungs
• Examples of drugs: eye drops, antiseptic, sunscreen, callous removal, nasal, etc.

Merits:

 

• Local therapeutic effects.
• Not well absorbed into the deeper layers of the skin or mucous membrane.
• Lower risk of side effects.
• Transdermal route offers steady level of drug in the system.
• Sprays for inhalation through the nose may be for local or systemic effects
• Stable blood levels.
• No first pass metabolism drug must be potent or patch becomes too large

Demerits:

• Excessive application causes irritation and burning on the skin.
• Can not be applying on wounded or broken skin.
• In case of administration   of drug to sensitive areas such as mucous membrane of eye,nose,vagina,etc care must be taken .
• In case of mucous membrane the administered drug preparation  should be sterile otherwise pathogen causes damage to the membrane.

 4) Pulmonary or Inhalation Route Of Drug Administration:

 

Pulmonary Route

Inhalation

• This route involves administration of drugs directly into the nose.
• in this way drugs can pass directly to the lungs.
• inhalation may be the route of choice to avoid the systemic effects.
• drugs used involve volatile drugs and gases.
• Examples include aerosols like salbutamol; steam inhalations include tincture and benzoin

Merits:

• Rapid absorption takes place.
• Rapid onset of action takes place.
• This route has minimum side effects.
• No first pass effect takes place.
• This method is easy.
• Fewer doses is required.

Demerits:

• Special apparatus such as inhalers is required.
• Irritation of the respiratory tract may take place.
• Cooperation of the patient is required.
• Airway must be patent.

-THE END-

References:

Lippincott's illustrated review:  pharmacology by richard harvey

5th edition published by wolters kluwer

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