Intramuscular injection antimicrobials

The activity of penicillin G was originally defined in units. Crystalline sodium penicillin G contains approximately 1600 units per mg (1 unit = 0.6 meg 1 million units of penicillin = 0.6 g). Semisynthetic penicillins are prescribed by weight rather than units. The minimum inhibitory concentration (MIC) of any penicillin (or other antimicrobial) is usually given in mcg/mL. Most penicillins are dispensed as the sodium or potassium salt of the free acid. Potassium penicillin G contains about 1.7 mEq of K+ per million units of penicillin (2.8 mEq/g). Nafcillin contains Na +, 2.8 mEq/g. Procaine salts and benzathine salts of penicillin G provide repository forms for intramuscular injection. In dry crystalline form, penicillin salts are stable for years at 4°C. Solutions lose their activity rapidly (eg, 24 hours at 20°C) and must be prepared fresh for administration. 

Several natural penicillins can be produced, depending on the chemical composition of the fermentation medium used to culture penicillium. Penicillin G (benzylpenicillin) has the greatest antimicrobial activity of these natural penicillins and is the only natural penicillin used clinically. However, penicillin G is not stable it is extremely acid-labile. Only about one-third of an oral dose is absorbed under the most ideal conditions. Therefore, it is generally not given orally but is administered by intramuscular injection. Several newer derivatives of penicillin G have been developed that do have good to excellent oral absorption (e.g., cloxacillin, ampicillin, and amoxicillin). 

The tetracyclines are amphoteric antimicrobial agents that can form salts with bases or acids (see Chs 1 and 2). Oxytetracycline is a bitter, yellow, odorless crystalline powder. The base is slightly water soluble and the hydrochloride is readily water soluble and is typically administered to horses by slow i.v. injection. It is effective at 5.5 mg/kg once daily for 2 days or more in the treatment of B. equi but is unlikely to completely clear this infection. It is, therefore, used for premunition. Rapid i.v. injection may cause a precipitous drop in blood pressure and collapse owing to the effects of calcium chelation on the myocardium. Intramuscular injection causes objectionable local reactions in horses and should be avoided. Oral administration may be more... 

Because of the slow elimination (long half-life) of antimicrobial agents in reptiles, dosage intervals are substantially longer in reptilian compared with mammalian species (Jacobson, 1993) (Table 6.14). To avoid significantly decreased systemic availability of drugs that are eliminated by renal excretion (e.g. (3-lactam and aminoglycoside antibiotics), the site of intramuscular injection should be the anterior half of the body most reptilian species have a well-developed renal portal system. 

Streptomycin is used for the treatment of certain unusual infections usually in combination with other antimicrobial agents. Because it is less active than other members of the class against aerobic gram-negative rods, it has fallen into disuse. Streptomycin may be administered by deep intramuscular injection or intravenously. The dose of streptomycin is 15 mg/kg/day for patients with creatinine clearances above 80 mL/min. It typically is administered as a 1000-mg single daily dose or 500 mg twice daily. The daily dose should be reduced in proportion to creatinine clearance for creatinine clearances >30 mL/min (Table 45-1). 

Hazardous Decomp. Prods. Heated to decomp., emits acrid smoke and irritating vapors Uses Surfactant, emulsifier for foods, cosmetics, pharmaceuticals, household prods., industrial applies., polymerization, pulp/paper, metalworking, lubricants, textiles, agric., paints, adhesives emulsifier in food pkg. oil additive corrosion inhibitor cosolvent stabilizer for foods antimicrobial in cane and beet sugar mills Regulatory FDA 21CFR 175.320, 178.3400 Europe listed UK approved FDA approved for intramuscular injectables NF, BP, EP compliance Manuf./Distrib. ASiE Connock http //www.connock.co.uk, Aldrich http //www.sigma-aldrich. com. Ash land... 

Absorption is the critical factor that determines entry of an antimicrobial agent into the blood stream when an extravascular route of administration, i.e. oral, intramuscular (IM), or subcutaneous (SC) injection is used. Absorption, the extent of which depends mainly on the physicochemical properties of the antimicrobial agent, is associated with intra-mammary or intra-uterine therapy. 

The residue profile of cefquinome in beef calves intramuscularly treated with the drug has been studied (86). The data were reminiscent of those form other cephalosporins and indicated that cefquinome was rapidly cleared, with detectable levels of significance seen at injection site, kidney, and liver tissues. However, the residues remaining after 12 h at the injection site, kidney, and liver were not antimicrobially active and/or bioavailable and no parent drug could be detected 80-100% of these residues were bound residues. 

Cresol is used at 0.15-0.3% concentration as an antimicrobial preservative in intramuscular, intradermal, and subcutaneous injectable pharmaceutical formulations. It is also used as a preservative in some topical formulations and as a disinfectant. Cresol is not suitable as a preservative for preparations that are to be freeze-dried. ... 

Penicillin G benzathine is absorbed very slowly from IM depots and produces the longest duration of detectable antibiotic of all the available repository penicillins. For example, in adults, a dose of 1.2 million units given intramuscularly produces concentration in plasma of 0.09 pg/mL on the first, 0.02 pg/mL on the fourteenth, and 0.002 pg/mL on the thirty-second day after injection. The average duration of demonstrable antimicrobial activity in the plasma is about 26 days. 

Penicillin G benzathine suspension is the aqueous suspension of the salt obtained by combining 1 mol of an ammonium base and 2 mol of penicillin G this provides a very slow release. The persistence of penicillin in the blood after an intramuscular dose reduces cost, need for repeated injections, and local trauma. The average duration of demonstrable antimicrobial activity in the... 

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