Ampicillin

Oral Antibiotics

Drug class: β-Lactam Antibiotics, is a broad-spectrum penicillin antibiotic.

Ampicillin（中文：安比西林）

Ampicillin is a broad-spectrum penicillin antibiotic used to treat various bacterial infections. Below is a detailed overview of its characteristics, usage, and percautions.

Common Strengths of Ampicillin

• 250 mg
• 500 mg

Drug Usage

Ampicillin is used to treat infection caused by susceptible bacteria, including:

• Respiratory tract infections
• Urinary tract infections
• Meningitis
• Gastrointestinal infections
• Gonorrhea
• Skin infections

Mechanism of Action

Ampicillin works by inhibiting bacterial cell wall synthesis, which leads to cell lysis and death of the bacteria.

Route of Administration

• Oral capsules
• Oral suspension
• Intravenous (IV) injection

Dosages

• Typically, the standard adult dosage is 250 mg to 500 mg every 6 hours for mild to moderate infections
• Renal Dosing: dosage adjustments are based on estimated glomerular filtration rate (eGFR):
  • eGFR >30 mL/min: Standard dosing
  • eGFR 15 to 30 mL/min: Reduce frequency to every 12 hours
  • eGFR <15 mL/min: Reduce frequency to once daily

Side Effects

Frequency	Adverse reactions
Common Side Effects	Nausea
	Vomiting
	Diarrhea
	Rash
Serious Side Effects	Allergic reaction (e.g. anaphylaxis)
	Clostridum difficile-associated diarrhea
	Severe skin reactions (e.g. Stevens-Johnson syndrome)

Pharmacokinetics

• Bioavailability: The bioavailability of ampicillin when taken orally is approximately 40-60%. Peak plasma concentrations are typically reached within 1 to 2 hours after oral administration.
• Half-Life: The elimination half-life of ampicillin is generally between 1 to 2 hours in healthy individuals. However, this half-life can extend significantly in patients with renal impairment, sometimes excedding 20 hours.
• Excretion: Ampicillin is primarily excreted unchanged in the urine.
• Onset of Action: Ampicillin typically begins to works within 1 to 2 hours after oral administration.
• Duration of Action: Effects generally last for 6 to 8 hours.

Drug Precautions

Pregnancy

Ampicillin is generally considered safe during pregnancy but should be used only if clearly needed.

Breastfeeding

It passes into breast milk in low levels; consult a healthcare provider before use while breastfeeding.

Children and Elderly

Use with caution; dosing may need adjustment based on age and weight, especially in pediatric patients.

Monitoring Requirements

Regular monitoring of renal function, liver function, and complete blood counts may be necessary during prolonged therapy.

Drug Interactions

Ampicillin can interact with various with medications, including:

• Probenecid (increase ampicillin levels)
• Allopurinol (increase risk of skin rash)
• Oral contraceptives (may reduce effectiveness)

FAQ

How Should I Take the Tablet?

Take ampicillin with a full glass of water, on an empty stomach (at least 30 minutes before or 2 hours after meals) for optimal absorption

What Should I Avoid While Taking?

Avoid alcohol.

'What Happens if I Miss a Dose?

Take the missed dose as soon as you remember, but skip it if it is almost time for your next dose. Do not double up.