Ampicillin, also known as ampicillin and ampicillin, is a beta-lactam antibiotic used to treat a variety of bacterial infections. Indications include respiratory tract infections, urinary tract infections, meningitis, salmonella infections, and endocarditis. This product can also be used to prevent group B streptococcus infection in neonates and can be administered orally, intramuscularly and intravenously. Aminopenicillins also include amoxicillin, which penetrates more Gram-negative bacteria than penicillin or penicillinase-resistant penicillins, but are easily broken down by bacterial beta-lactamases, so they are often combined with sulbactam (a beta-lactam). Enzyme Inhibitors) to enhance the therapeutic effect against β-lactamase-producing bacteria. Ampicillin was first discovered in 1961. The drug is listed on the World Health Organization Model List of Essential Medicines and is one of the essential medicines for the basic public health system. In 2014, the wholesale price of each intravenous injection was about $0.13 to $1.20. The drug is a generic drug, and a ten-day course of treatment costs about $13.
2. What is the pharmacokinetics of ampicillin sodium?
After intramuscular injection of 0.5g, the peak plasma concentration of 12μg/ml was reached in 0.5 to 1 hour; after intravenous injection of 0.5g, the blood concentration was 17μg/ml and 0.6μg/ml after 15 minutes and 4 hours, respectively. Widely distributed in pleural effusion, joint effusion, aqueous humor and breast milk, and the concentration is high. The concentration in bile is several times higher than the blood concentration. Permeable through the placental barrier, but through the blood. CSF barrier capacity is low. The protein binding rate is 20% to 25%. The half-life is about 1.5 hours, and the half-life of renal insufficiency can be extended to 7 to 20 hours. 12% to 50% of drugs are metabolized in the liver, and some are secreted by glomerular filtration and renal tubules .
Ampicillin is well absorbed after administration. Normal people take 0.5g and 1g on an empty stomach, and the peak plasma concentration is reached after 2 hours, which are 5.2μg/ml and 7.6μg/ml, respectively; 0.5g is intramuscularly injected, and the peak plasma concentration is reached in 0.5-1h, which is about 12μg/ml; The plasma concentrations of 15min and 4h after intravenous injection of 0.5g were 17μg/ml and 0.6μg/ml, respectively. 1 hour after intramuscular injection of 10 mg/kg and 25 mg/kg in neonates and premature infants, the plasma concentrations reached their peak values of 20 μg/ml and 60 μg/ml, respectively. The drug is widely distributed in the body after absorption. The drug concentration in pleural effusion, joint effusion, aqueous humor and breast milk is higher. The concentration of ampicillin in bile is several times higher than that in blood; the concentration in bronchial secretion fluid of patients with pulmonary infection is 1/50 of the blood concentration in the same period; the concentration in serum of pregnant women is significantly lower than that in pregnancy. Ampicillin can pass through the placental barrier, and the amniotic fluid can maintain a certain blood concentration continuously. The ability of ampicillin to pass through the normal meninges is low, and the normal cerebrospinal fluid contains only a small amount of the drug, but the concentration of the drug increases significantly when the meninges are inflamed. The volume of distribution of ampicillin is 0.28L/kg, and the protein binding rate is 20% to 25%.
The half-life of healthy adults is 1.5h, and the half-life of neonates and premature infants is 1.0 to 1.2h. 12% to 50% of the drug is metabolized in the liver. The renal clearance of ampicillin is slightly slower than that of penicillin, partly through glomerular filtration and tubular secretion. The 24-hour urine excretion is 20% to 60% by oral administration, 50% by intramuscular injection, and 70% by intravenous injection. In patients with renal insufficiency, the half-life can be extended to 7 to 20 hours. Hemodialysis is effective in removing the drug, but peritoneal dialysis has no effect on ampicillin clearance.
3. What are the precautions for ampicillin sodium?
(1) If severe persistent diarrhea occurs during the treatment, it may be pseudomembranous colitis, and the drug should be stopped immediately, and corresponding antibiotic treatment should be used after diagnosis.
(2) It decomposes faster in weakly acidic glucose solution, so neutral infusion should be used as solvent. Use immediately after dissolving.
Other same as penicillin:
(1) First, inquire about allergy history in detail. People with allergy history are generally not suitable for skin test.
(2) Skin test should be carried out according to the prescribed method before administration (concentration of 500 units/ml, intradermal injection of 0.05 to 0.1 ml).
(3) Once the symptoms of anaphylactic shock appear, 0.5-1ml of 0.1% epinephrine should be injected intramuscularly immediately. If the clinical manifestations do not improve, repeat it once after half an hour, and cooperate with other symptomatic treatment at the same time.
(4) This product is not suitable for intrathecal injection. It can be administered intramuscularly or intravenously. When the daily dose of adults exceeds 5 million units, it should be drawn intravenously. The speed of intravenous administration should not exceed 500,000 units per minute, and it should be instilled rapidly in divided doses, generally once every 6 hours, to avoid central nervous system reactions.
(5) Patients with a history of allergic diseases such as asthma, eczema, hay fever, urticaria, etc. should be used with caution. Patients with severe renal impairment should adjust the dose or prolong the dosing interval.
(6) When large doses are administered, the introduced sodium or potassium ions should be considered, which can cause hypernatremia or hyperkalemia. 1 million units of penicillin sodium contains 1.7 mmol (39 mg) of sodium ions; 1 million units of penicillin G potassium contains 1.5 mmol (65 mg) of potassium ions.
(7) The aqueous solution of this product is unstable and easy to be hydrolyzed. Therefore, the injection should be prepared fresh. When it must be stored, it should be refrigerated and used up within 24 hours.
4. What are the drug interactions of ampicillin sodium?
(1) Combination with probenecid, aspirin, indomethacin and sulfa drugs can reduce the excretion of penicillin drugs, increase the blood concentration of penicillin drugs, and enhance the effect, but the toxicity may also increase.
(2) Combination with tetracyclines, erythromycin, chloramphenicol and sulfonamides and other antibacterial drugs may reduce the antibacterial effect of this product.
The combined application of ampicillin and chloramphenicol has different effects on the antibacterial effect of influenza bacillus in vitro. Chloramphenicol has no antagonism to ampicillin at high concentrations (5-10 mg/L), and can weaken the bactericidal effect of ampicillin at low concentrations (1-2 mg/L), but has no antibacterial effect on chloramphenicol. influences. And when the two drugs are used together to treat bacterial meningitis, the incidence of long-term sequelae is higher than when the two drugs are used alone.
(3) Combined use with warfarin can enhance the anticoagulant effect.
(4) Taking contraceptive pills at the same time may affect the contraceptive effect.
Ampicillin can stimulate estrogen metabolism or reduce its enterohepatic circulation, reducing the efficacy of oral contraceptives.
(5) kanamycin can enhance the in vitro antibacterial effect of ampicillin on Escherichia coli, Proteus and Enterobacter.
(6) Gentamicin can enhance the bactericidal effect of ampicillin on group B streptococcus in vitro.
(7) The combination of ampicillin and clavulanic acid can reduce the minimum inhibitory concentration against β-lactamase-producing gonococcus from 64 μg/ml to 4 μg/ml.
(8) Lincomycin can inhibit the antibacterial effect of ampicillin against Staphylococcus aureus in vitro.
(9) Allopurinol can increase the incidence of ampicillin skin and mucous membrane reactions, especially in patients with hyperuricemia.
(10) Chloroquine can reduce the absorption of ampicillin by 19% to 29%.
(11) Ampicillin decomposes quickly in weakly acidic glucose solution, so neutral liquid should be used as solvent.