Penicillin parenteral

Parenteral penicillin is the drug of choice for all stages of syphilis. 

Parenterally administered penicillin is recommended for all stages of syphilis. Alternative agents may be used in allergic individuals and include doxycycline, minocycline, tetracycline, or erythromycin base or stearate. Some patients may not respond favorably to alternative modalities. Therefore, in patients who must be administered penicillin (i.e., patients who are pregnant or have central nervous system [CNS] involvement) or are allergic, desensitization must be performed before the drug is initiated. 

In contrast, parenteral suspensions have relatively low solids contents, usually between 0.5 and 5%, with the exception of insoluble forms of penicillin in which concentrations of the antibiotic may exceed 30%. These sterile preparations are designed for intramuscular, intradermal, intralesional, intraarticular, or subcutaneous injection. Syringeability is an important factor to be taken into consideration with injectable dosage forms. The viscosity of a parenteral suspension should be sufficiently low to facilitate injection. Common suspending vehicles include preserved isotonic saline solution or a parenterally acceptable vegetable oil. Ophthalmic and optic suspensions that are instilled into the eye/ear must also be prepared in a sterile manner. The vehicles are essentially isotonic and aqueous in composition. The reader should refer to Chapter 12 for further discussion on parenteral products. 

If the solubility of a drug is to be reduced to enhance stability or to prepare a suspension, the for-mulator may prepare water-insoluble salts. A classic example is procaine penicillin G, the decreased solubility (7 mg/mL) of which, when compared with the very soluble penicillin G potassium, is utilized to prepare stable parenteral suspensions. Another alternative to preparing an insoluble drug is to use the parent acidic or basic drug and to buffer the pH of the suspension in the range of minimum solubility. 

Two basic methods are used to prepare parenteral suspensions (a) sterile vehicle and powder are combined aseptically, or (b) sterile solutions are combined and the crystals formed in situ. Examples of these procedures may be illustrated using Penicillin G Procaine Injectable Suspension USP and Sterile Testosterone Injectable Suspension USP. 

The answer is b. (Hardman, pp 1077—1086.) Piperacillin is a broad-spectrum, semisynthetic penicillin for parenteral use. Its spectrum of activity includes various Gram-positive and Gram-negative organisms including Pseudomonas. The indications for piperacillin are similar to those for car-benicillin, ticarcillin, and mezlocillin, with the primary use being sus-... 

The answer is a. (Hardman, pp 1143-1144.) Polymyxin B is poorly absorbed by the oral route. It is primarily administered by the topical route for the treatment of infections of the skin, mucous membranes, eye, and ear. Penicillin G can be administered both orally and parenterally. Did oxacillin is only given by the oral route. Carbenicillin and streptomycin are administered only by the parenteral route. 

Treatment recommendations from the CDC for syphilis are presented in Table 46-6. Parenteral penicillin G is the treatment of choice for all stages of syphilis. Benzathine penicillin G is the only penicillin effective for single-dose therapy. 

In penicillin-allergic patients, oral or parenteral clindamycin may be used. Alternatively, a first-generation cephalosporin such as cefazolin (1 to 2 g IV every 6 to 8 hours) may be used cautiously for patients who have not experienced immediate or anaphylactic penicillin reactions and are penicillin skin test negative. In severe cases in which cephalosporins cannot be used because of documented methicillin resistance or severe allergic reactions to /1-lactam antibiotics, IV vancomycin should be administered. 

Co-amoxiclav consists of the combination of amoxicillin (penicillin antibacterial agent) and clavulanic acid (beta-lactamase inhibitor) which is associated with a risk of crystalluria in patients with renal impairment who are receiving high doses, particularly during parenteral therapy. 

Cefalexin is a first-generation cephalosporin and therefore an alternative preparation would be Zinnat tablets, which contains cefuroxime, a second-generation cephalosporin. A penicillin such as Augmentin, which contains co-amoxiclav, can be an appropriate alternative since it provides a very similar spectrum of activity. Klaricid contains clarithromycin, which is a macrolide. Utinor contains norfloxacin, which is a quinolone that is effective in uncomplicated urinary-tract infections. Rocephin contains ceftriaxone, which is a third-generation cephalosporin that is available for parenteral administration only. 

Absorption - Peak serum levels occur approximately 1 hour after oral use. Parenteral penicillin G (sodium and potassium) gives rapid and high but transient blood levels derivatives provide prolonged penicillin blood levels with IM use. 

Drugs that may affect penicillins include allopurinol, aminoglycosides (parenteral), aspirin, beta blockers, chloramphenicol, erythromycin, ethacrynic acid, furosemide, indomethacin, phenylbutazone, probenecid, sulfonamides, tetracycline, and thiazide diuretics. Drugs that may be affected by penicillins include aminoglycosides (parenteral), anticoagulants, beta blockers, chloramphenicol, cyclosporine, oral contraceptives, erythromycin, heparin, and vecuronium. 

Parenteral Serious or severe infections not treatable with other antimicrobials, including the penicillins and cephalosporins. 

In fasciitis or necrotizing infections caused by beta-hemolytic streptococci of group A, parenteral high-dose penicillin combined with clindamycin is the treatment of choice. For the treatment of abscesses, antibiotics which are able to kill large quantities of resting bacteria, such as clindamycin and the quinolones, are preferred. 

Mezlocillin, piperacillin, and ticarcillin are parenteral antibiotics formulated as sodium salts, so prescribers must consider the sodium content of these antibiotics when administering them to patients with congestive heart failure. During their distribution phase, antipseudomonal penicillins achieve orfly low concentrations in the cerebrospinal fluid. Consequently, antipseudomonal penicillins are not among the drugs of first choice for meningitis therapy. 

L D. Doxycycline is the preferred parenteral tetracycline for the primary state of Lyme disease in adults and children older than 8 years of age. Penicillin V (A) would be ineffective. Erythromycin (B) and clarithromycin (C) also are not effective against Borrelia burgdorferi, the gram-negative anaerobe organism responsible for Lyme disease. 

Cephalosporins are distributed in the body after oral or parenteral administration in same manner as penicillin is distributed. The majority are not metabolized and are eliminated by kidney. 

Parenteral preparations containing fixed dose combination of streptomycin with penicillin. 

Penicillin concentrations in most tissues are equal to those in serum. Penicillin is also excreted into sputum and milk to levels 3-15% of those in the serum. Penetration into the eye, the prostate, and the central nervous system is poor. However, with active inflammation of the meninges, as in bacterial meningitis, penicillin concentrations of 1-5 mcg/mL can be achieved with a daily parenteral dose of 18-24 million units. These concentrations are sufficient to kill susceptible strains of pneumococci and meningococci. 

Parenteral 0.6, 1.2, 2.4 million units per dose Penicillin G procaine (generic)... 

Kanamycin is an aminoglycoside complex produced by Streptomyces ka-namyceticus. It is comprised of three components, kanamycin A being the major component and kanamycins B and C minor congeners. Kanamycin is active against many pathogenic bacteria and has been used parenterally for treatment of bovine respiratory disease, mastitis, and other infectious conditions. A popular combination used in horses and cattle with respiratory disease is kanamycin and penicillin G. It is also used orally for treatment of bacterial enteritis because limited absorption occurs after oral administration. 

The rates of absorption, clearance, and elimination of penicillin G are further influenced by the route of administration. Intramuscular and subcutaneous injections provide drug to the bloodstream more slowly, but maintain concentrations longer than the intravenous administration. Absorption of penicillin G from intramuscular or subcutaneous sites can be further slowed down by the use of the relatively insoluble procaine salt. When equivalent dosages of penicillin G and procaine penicillin G were injected parenterally, peak residues concentration in blood occurred after 2 h and the drug had cleared the blood by 8 following penicillin G administration. With the procaine penicillin G, peak residues concentration appeared 5 h after injection and the drug cleared the plasma 24 h after administration (57). 

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