Suppositories: Definition and Advantages

Study Notes

Suppositories are solid dosage forms designed for insertion into body orifices (rectum, vagina, urethra).
They melt, soften, or dissolve within the body, delivering a local or systemic effect.

Bypass first-pass metabolism: Offers an alternative for drugs with poor oral bioavailability.
Suitable for drugs destroyed by portal circulation: Prevents drug degradation before reaching systemic circulation.
Effective in cases of nausea and vomiting: Allows administration when oral intake is impossible.
Suitable for drugs with unpleasant odour and taste: Masks unpleasant characteristics of the drug.
Systemic distribution for unconscious patients: Provides an alternative route for patients unable to take drugs orally.
Minimal irritation in the stomach: Appropriate for drugs that irritate the gastrointestinal tract.
Administration of drugs susceptible to gastric pH and enzymes: Protects sensitive drugs from degradation in the stomach.
Faster onset of action than oral route: Direct absorption from mucosa into venous circulation.
Rapid and direct local effect for rectal, vaginal, and urethral conditions: Provides targeted treatment for localized disorders.
Accurate dosage forms: Provides reliable and precise drug delivery.
Suitable for pediatric and geriatric patients: Alternative for individuals with difficulty swallowing oral medications.

Patient acceptance: May be considered embarrassing for some patients.
Limited rectal fluid content: Potential impact on dissolution rate and drug absorption.
Not suitable for patients with diarrhea: May hasten bowel evacuation and reduce drug absorption.
Storage requirement: Need to be stored at low temperatures to maintain stability.
Potential for irritation or large dosage: High drug concentration in suppository may cause irritation or limit dosage.
Incomplete absorption: Suppositories might promote bowel evacuation and result in incomplete drug absorption.
Potential drug degradation by rectal flora: Some drugs might be degraded by microorganisms present in the rectum.

Local Relief:
- Hemorrhoids
- Acute constipation
- Rectal inflammation or ulcers
Systemic Absorption:
- Nausea and vomiting
- Fever and pain
- Hormonal therapy
Before endoscopic examination: To clear the rectal cavity for better visualization.
To empty the bowel before surgery: Facilitates bowel preparation for surgical procedures.

Severe rectal conditions: Rectal bleeding or severe hemorrhoids.
Known hypersensitivity or allergy: To the drug or excipient.
Rectal surgery: May irritate the surgical site or interfere with healing.
Obstruction or severe stricture: May be difficult to insert or could worsen the condition.
** Diarrhea:** May further promote bowel movements and reduce drug efficacy.
Chronic constipation: May lead to dependence and repetitive use.
Paralytic ileus: May cause discomfort or worsen the condition.

Shape and size must be appropriate for:
- Easy insertion into the target orifice.
- Retention for the required duration.

Rectal Suppositories:
- Shape: Torpedo-shaped
- Weight: 1g for children, 2g for adults
- Length: About 3 cm
Urethral Suppositories:
- Shape: Pencil-shaped.
- Weight: 2g and 60-75 mm long for females, 4g and 100-150 mm for males.
Vaginal Suppositories:
- Shape: Oviform
- Weight: About 3-5g
- Used for treatment of infections and contraception.
Nasal Suppositories:
- Weight: About 1g
- Used for nasal delivery of drugs.
Ear Cones (Aurinaries):
- Shape: Cylindrical
- Weight: About 1g
- Less commonly used.