drugs

Subcutaneous route of administration

Administration routes

  • enteral
    • Oral
    • Sublingual
    • Rectal
  • parenteral
    • Intravenous
    • Intramuscular
    • subcutaneous
  • INHALATION
  • TRANSCUTANEOUS

The subcutaneous route requires the drug to be administered through a syringe into the subcutaneous tissue. It is however very difficult to establish the exact point at which to administer, because it depends on the inclination of the needle and on the staff performing the operation.

With the subcutaneous route, local effects (such as a local anesthetic) or systemic effects (for example, a drug that acts systemically, such as insulin) can be achieved. In the subcutaneous route, compared to the intramuscular route, the injectable volume (max. 2 ml.) Is much lower, the absorption much slower and the pain more intense, given that the skin tissue has many more nociceptive endings than the muscle. The speed of absorption depends on the degree of spraying in the area, so it must be remembered that if a localized effect is to be obtained, the drug will be associated with a vasoconstrictor. If you want to increase the area of ​​contact, the medicine will be associated with the enzyme hyaluronidase, which thanks to its activity reduces the consistency of collagen.

The recommended sites for subcutaneous injection are:

  • the upper outer part of the arms
  • the periombelical area of ​​the abdomen
  • the front of the thighs

The skin should be raised to avoid injecting the drug into the muscle and the needle should be inserted at an angle of 90 ° to the skin surface; important is the rotation of the injection sites.

ADVANTAGES:

  • the absorption of the aqueous solutions is rapid;
  • absorption can be slowed by adding a vasoconstrictor;
  • it is a way suitable for the implantation of tablets or pellets;
  • little training is needed to perform this type of administration;
  • suitable for frequent administration.

DISADVANTAGES:

  • irritating drugs can cause pain and necrosis;
  • does not allow the administration of large volumes;
  • a certain variability of absorption is possible.

Subcutaneous implants

With regard to subcutaneous administration, the possibility of performing small subcutaneous implants should also be mentioned. The implant consists in lifting the upper part of the skin and inserting a solid pharmaceutical form containing a specific active ingredient. In this way the molecule will dissolve much more slowly, giving a deferred effect over time. Thanks to these implants you can for example administer steroid hormones (a method used in women entering menopause) or insulin in crystallized form, which can be inserted subcutaneously avoiding injection.