Vaginal Drug Administration
Leila has an exam in Pharmacology next week, and with this being one of the toughest subjects in nursing school, she decided to start studying tonight. That way, she wouldn’t cram and would even have time to research more about concepts that she finds complicated.
Tonight she is reading all about drug routes. Intravenous, okay, she has read about that, check! Intradermal, subcutaneous and intramuscular injections, check! Sublingual, check! Vaginal… wait, what? There is a vaginal route when administering drugs? Confused and now intrigued, she decides to read on about this route, its benefits and when it should be used.
Why the vaginal route
Although clinicians normally use topically administered drugs in the vagina, this route for systemic drug administration is somewhat novel. According to research, the vagina is a highly effective site for drug delivery, particularly in women’s health. It is also an ideal route for drug administration since it allows for the administration of lower doses, steady drug levels, and less frequent administration than the oral route.
According to Dr. Anita L. Nelson, who presented a brief overview of the anatomy, histology, and immunology of the vagina, the vagina has a rich system of defenses and dynamic microbiology, as well as a rich vascular plexus that makes it ideal for absorbing drugs. Furthermore, studies show that with vaginal drug administration, absorption is unaffected by gastrointestinal disturbances, there is no first-pass effect, and use is discreet.
Advantages of vaginal administration
- Generally there is less drug degradation via this route of administration compared to oral administration
- The dose can be retrieved if necessary
- There is the potential of long term drug absorption with various intrauterine devices (IUDs).
- It should also be noted that vaginal administration lead to variable absorption since the vagina is a physiologically and anatomically dynamic organ that causes pH and membrane permeability to change over time.
- There is also a tendency of some dosage forms to be expelled after insertion into the vagina.
Vaginal formulations include solutions, powders for solutions, ointments, creams, aerosol foams, suppositories, and tablets.
Vaginal suppositories are employed as contraceptives, feminine hygiene antiseptics, bacterial antibiotics, or to restore the vaginal mucosa. Vaginal suppositories are inserted high in the vaginal tract with the aid of a special applicator. The suppositories are usually globular, oviform, or cone-shaped and weigh between 3 – 5 grams. Patients should be instructed to quickly dip the suppository in water before insertion. Because suppositories are generally used at bedtime and can be messy if the formulation is an oleaginous base, patients should wear a sanitary napkin to protect nightwear and bed linens.