Routes of administration

The route of administration is the method used to introduce a drug into the body. Routes are broadly grouped into enteral and parenteral routes.

• Enteral routes deliver the drug into the gastrointestinal (GI) tract (for example, oral or rectal administration).
• Parenteral routes bypass the GI tract (for example, intravenous injection). Parenteral routes bypass the first-pass effect.

Types of enteral routes

1. Oral: Administration to or by way of the mouth.
2. Sublingual: Administration beneath the tongue.
3. Buccal: Administration directed toward the cheek, generally from within the mouth.
4. Rectal: Administration to the rectum.

Types of parenteral routes

1. Intravenous: Administration within or into a vein or veins.
2. Intramuscular: Administration within a muscle.
3. Subcutaneous or subdermal: Administration beneath the skin; hypodermic.
4. Intraarterial: Administration within an artery or arteries.
5. Intrathecal: Administration within the cerebrospinal fluid at any level of the cerebrospinal axis, including injection into the cerebral ventricles or into the fluid filled space between the spinal cord and the membrane surrounding it.
6. Intradermal: Administration within the dermis.
7. Intraperitoneal: Administration within the peritoneal cavity.
8. Intraosseous: Administration into the medulla of bone.

Other routes of administration

1. Otic or auricular route: Administration to or by way of the ear.
2. Ocular or ophthalmic route: Administration within the eye.
3. Nasal route: Administration to the nose; administered by the nose.
4. Vaginal route: Administration into the vagina.
5. Transdermal: Administration through the dermal layer of the skin to the systemic circulation by diffusion.
6. Inhalation: Administration within the respiratory tract by inhaling orally or nasally for local or systemic effect.
7. Nebulization: The use of nebulizers to administer drug aerosols into the lungs.
8. Pump: A medical device used to deliver drugs or fluids into a patient’s body in a controlled manner. It is commonly used to deliver insulin, pain medications, chemotherapy drugs, etc.
9. Urethral: Administration into the urethra.
10. Topical: Administration to a particular spot on the outer surface of the body or skin.

Special handling and hazardous drugs

The National Institute for Occupational Safety and Health (NIOSH) considers a drug hazardous if it exhibits one or more of the following characteristics in humans or animals:

• carcinogenicity
• teratogenicity, or developmental toxicity
• reproductive toxicity
• organ toxicity at low doses
• genotoxicity
• structure and toxicity profiles of new drugs that mimic existing hazardous drugs

These include various antineoplastic and cytotoxic medications, anesthetic agents, antiviral agents, etc. Examples include warfarin, fluorouracil (5-FU), cyclophosphamide, tamoxifen, and oxytocin.

Exposure to hazardous drugs can occur through inhalation or direct skin contact, especially during preparation and handling activities such as:

• labeling drug containers
• transferring or reconstituting medications
• withdrawing needles from drug vials
• needle or sharp handling and disposal

Personal protective equipment (PPE), such as gloves and masks, should be worn while handling hazardous medications (for example, when counting tablets on a tray). Hazardous drugs must be stored separately from other medications on a separate shelf and clearly marked. Special bags should be used to dispose of hazardous medications, and separate counting trays should be used to count hazardous drugs.