【Main Components】 Potassium Penicillin

【Properties】 This product is a white crystalline powder.

【Pharmacological Effects】 Pharmacodynamics: Penicillin belongs to bactericidal antibiotics, with strong antibacterial activity. Its antibacterial mechanism mainly involves inhibiting the synthesis of the cell wall glycopeptide in bacteria. During the growth phase, sensitive bacteria divide vigorously, with the cell wall in the biosynthesis stage. Under the action of penicillin, the synthesis of glycopeptide is blocked, preventing the formation of the cell wall and causing cell membrane rupture and death. For bacteria in the non-growing and non-reproducing phase, this is not necessary for cell wall synthesis, and penicillin does not have a bactericidal effect. Such "replication-phase bactericidal agents" should not be used in combination with "fast-acting antibacterial agents" that inhibit bacterial growth and reproduction (such as florfenicol, tetracycline class, erythromycin, etc.). The latter cause the bacteria to be in a growth inhibition state, preventing the bactericidal effect of penicillin.Penicillin is a narrow-spectrum antibiotic, mainly effective against various Gram-positive bacteria and a few Gram-negative bacteria. The main sensitive bacteria include Staphylococcus, Streptococcus, swine erysipelas bacillus, coccobacillus, tetanus bacillus, actinomycetes, anthrax bacillus, spirochetes, etc. It is not sensitive to mycobacteria, mycoplasma, chlamydia, rickettsia, Nocardia, fungi, and viruses.

Pharmacokinetics: Penicillin potassium salt is rapidly absorbed after intramuscular injection, reaching the peak blood concentration within 15 to 30 minutes. The blood concentration of penicillin maintained above 0.5 mg/ml for 6 to 7 hours after intramuscular injection. Penicillin can widely distribute throughout the body tissues and can enter the fetal circulation. The concentrations are higher in the kidneys, liver, lungs, muscles, small intestine, and spleen; the contents in bones, saliva, and breast milk are lower. It is difficult to enter the cerebrospinal fluid, and its concentration in normal cerebrospinal fluid is only 1% to 3% of the blood concentration. The concentration in cerebrospinal fluid during inflammation can reach 5% to 30% of the blood concentration. The concentration of penicillin in breast milk can be 5% to 20% of the blood concentration. When penicillin is injected into the breast milk, a large amount can be absorbed in the first few hours, but the antibacterial concentration can be maintained in the breast milk for a considerable period of time. It has been reported that when 100,000 units of penicillin solution are injected into the breast milk, it can remain at a concentration of 4.26 units/ml in the breast milk for 24 hours.

A small portion of penicillin is metabolized in the liver, and most is excreted in its original form. Under normal renal function, 50% to 75% is excreted by the kidneys, with 90% through renal tubular secretion. Due to the rapid excretion, the elimination in the body is relatively fast. The plasma protein binding rate of penicillin is approximately 50%. The half-life is short, with small differences among species, and the half-life for all domestic animals is 0.5 to 1.2 hours. The apparent volume of distribution is also small, generally 0.2 to 0.3 L/kg, with a higher blood concentration and lower tissue concentration.

【Drug Interactions】 (1) Penicillin combined with aminoglycosides can increase the concentration of the latter in the bacterial body, showing a synergistic effect.

(2) Macrolides, tetracycline class, and amide alcohol class and other fast-acting antibacterial agents interfere with the bactericidal activity of penicillin, and should not be used in combination.

(3) Heavy metal ions (especially copper, zinc, mercury), alcohols, acids, iodine, oxidants, reducers, hydroxyl compounds, acidic glucose injection solution or hydrochloric acid tetracycline injection solution, etc. can destroy the activity of penicillin. Such combinations are prohibited. 

(4) Amines can form insoluble salts with penicillin, which can delay the absorption of penicillin. For example, procaine penicillin.

(5) The aqueous solution of penicillin potassium and some drug solutions (such as chlorpromazine hydrochloride, lincomycin hydrochloride, desmopressin tartrate, oxytetracycline hydrochloride, tetracycline hydrochloride, B vitamins and vitamin C) should not be mixed, otherwise turbidity, flocculent substances or precipitation may occur.

[Indications] Mainly used for Gram-positive bacterial infections, also for infections caused by actinomycetes and leptospira, such as swine erysipelas, emphysematous gangrene, malignant edema, actinomycosis, swine adenitis, necrotic bacillus disease, leptospira disease and mastitis, skin and soft tissue infections, arthritis, uterine inflammation, pyelonephritis, pneumonia, sepsis and tetanus. When treating tetanus, it is advisable to use in combination with tetanus antitoxin.

[Usage and Dosage] Intramuscular injection: The dosage is 10,000 - 20,000 units per 1 kg of body weight for horses, cattle, sheep, calves and foals; 20,000 - 30,000 units for dogs, cats, and 30,000 - 40,000 units for poultry. Take 2 - 3 times a day for 2 - 3 days.

Before use, add an appropriate amount of sterilized injection water to dissolve.

[Adverse Reactions] (1) The main adverse reactions are allergic reactions, which can occur in most domestic animals, but the incidence is relatively low. Local reactions include edema and pain at the injection site, and systemic reactions include urticaria and rash. Severe cases may cause shock or death.

(2) For some animals, penicillin can induce secondary infections in the gastrointestinal tract.

[Precautions] (1) Penicillin potassium is easily soluble in water, and the aqueous solution is unstable, easily hydrolyzed, and the hydrolysis rate increases with the increase of temperature. Therefore, the injection solution should be prepared before use. When necessary for storage, it should be stored in the refrigerator (2 - 8°C), and can be stored for 7 days. At room temperature, it can only be stored for 24 hours.

(2) It is necessary to understand the interactions with other drugs and contraindications to avoid affecting the efficacy of penicillin.

(3) Penicillin potassium 1,000,000 units (0.625g) contains 0.065g of potassium ions. High potassium levels may occur with large-dose injections. It can have adverse effects on animals with reduced renal function or cardiac insufficiency. The adverse effects of potassium ions on the heart are more serious.

[Withdrawal Period] Cattle, sheep, pigs, poultry: 0 days; Cattle, sheep: 72-hour lactation period.

[Specification] Based on C16 H17 KN2 O4S      (1) 0.25g (400,000 units)       (2) 0.5g (800,000 units)      (3) 0.625g (1,000,000 units)     (4) 1.0g (1,600,000 units)      (5) 2.5g (4,000,000 units)