Ciprofloxacin concentrations in tonsils following a single intravenous infusion

Oral ciprofloxacin for treatment of acute bacterial pharyngotonsillitis

The clinical efficacy and tolerability of ciprofloxacin orally administered at the dosage of 250 mg twice a day was evaluated in 25 patients affected by acute bacterial pharyngotonsillitis. All patients were non-responders to previous conventional antibiotic therapies due to in vitro resistance of the responsible bacteria, or possibly the low antibiotic concentration at the infection site. None of the patients had infections caused by group A beta-haemolyticus streptococcus. Treatment with ciprofloxacin lasted for 5-10 days (mean 6.7). A favorable clinical response was observed in 92% of patients (15 resolutions and 7 improvements) at the end of the therapy and two weeks later (follow-up). One patient was not evaluable because of the unfortunate onset of glossitis that caused the interruption of the treatment. No other side-effects were recorded in the other 24 patients. The bacteriological response was excellent: 83% bacteriological eradication, 13% persistence and super-infection in only one patient (4%). Ciprofloxacin administered orally at low dosages is highly effective in the treatment of bacterial pharyngotonsillitis and is also well tolerated.

Extravascular penetration of ciprofloxacin. A review

The pharmacokinetics of ciprofloxacin after oral and intravenous administration have been studied extensively, and the results have been published worldwide. This paper serves as a review of the pharmacokinetics of ciprofloxacin, with specific reference to its penetration into body fluids and tissues. Ciprofloxacin has a protein binding of approximately 30% and penetrates well into tissues. For instance, the total concentration (area under the serum concentration-time curve) in peripheral human lymph is 70% of the serum values, and the peak level in lymph appears with 1-2 hr. The corresponding value for suction skin blisters is 60% and for inflammatory blisters 120%. Ciprofloxacin is concentrated in white blood cells, lung, prostate, and kidney and reaches concentrations above serum in many other tissues as well. Urine concentrations are up to 100 times those in serum. The levels in bile are comparable or only slightly higher (less than or equal to x 10) than serum levels. The penetration into cerebrospinal fluid (CSF) is low; the CSF levels are 4-10% of the serum levels in noninflammatory CSF and 30-50% in CSF from patients with meningitis.

Clinical pharmacokinetics of the newer antibacterial 4-quinolones

Structural modification of the so-called 'first-generation' or 'urinary' quinolones has led to a considerable increase in their intrinsic antibacterial activity, together with marked changes in the pharmacokinetic properties. Tissue penetration is the most notable change, and the newer quinolones are comparable with the newer broad spectrum beta-lactams in their clinical spectrum of activity. Marketed compounds in the 4-quinolones group include pefloxacin, ofloxacin, enoxacin, ciprofloxacin and norfloxacin; many more compounds are in various stages of research and development. The 4-quinolones act by inhibition of bacterial DNA gyrase, a process which is pH and concentration dependent. The bactericidal activity can be partly abolished if protein synthesis is inhibited by chloramphenicol, or if RNA synthesis is inhibited by rifampicin (rifampin). The antibacterial spectrum of activity includes methicillin- and gentamicin-resistant staphylococci, multiresistant non-fermenters, all Enterobacteriaceae, Legionella, Neisseria species, Branhamella and Haemophilus influenzae. With the exception of norfloxacin, which is only 30 to 40% bioavailable from the oral route, the 4-quinolones are 80 to 100% bioavailable, absorption occurring within 1 to 3 hours. Food does not significantly alter Cmax, AUC or elimination half-life, although tmax, may be increased. The 4-quinolones are widely distributed throughout the body, with volumes of distribution greater than 1.5 L/kg. Protein binding is less than 30% in most cases. Penetration into most tissues is good. With the exception of ofloxacin and lomefloxacin (NY 198), which are metabolically stable, metabolism of the 4-quinolones occurs primarily at the C7 position in the piperazinyl ring. Biotransformation is extensive (85%) with pefloxacin, medium (25 to 40%) with ciprofloxacin and enoxacin, and low (less than 20%) with norfloxacin. Elimination half-lives vary between 3 and 5 hours (ciprofloxacin) and 8 to 14 hours (pefloxacin). Biliary concentrations of the 4-quinolones are 2 to 10 times greater than those in serum or plasma, with several compounds undergoing enterohepatic circulation. There is some evidence that ciprofloxacin, norfloxacin, ofloxacin and enoxacin have an active renal tubular excretion pathway. In impaired renal function, reduction of the glomerular filtration rate below 30 ml/min (1.8 L/h) is associated with an increase in elimination half-life and AUC, and a decrease in renal and total clearance of the 4-quinolones, and a decrease in 24-hour urinary recovery.(ABSTRACT TRUNCATED AT 400 WORDS)

Ciprofloxacin: chemistry, mechanism of action, resistance, antimicrobial spectrum, pharmacokinetics, clinical trials, and adverse reactions

Ciprofloxacin, considered a benchmark when comparing new fluoroquinolones, shares with these agents a common mechanism of action: inhibition of DNA gyrase. While ciprofloxacin demonstrated a fairly good activity against gram-positive bacteria, it is against gram-negative organisms that it proved to be more potent than other fluoroquinolones. It is the most active quinolone against Pseudomonas aeruginosa, with MIC90s on the order of 0.5 micrograms/ml. When given orally, ciprofloxacin exhibited 70% bioavailability and attained peak serum levels ranging between 1.5 and 2.9 micrograms/ml after a single 500-mg dose. Nineteen percent of an oral dose was excreted as metabolites in both urine and feces. In most cases, body fluids and tissue concentrations equaled or exceeded those in concurrent serum samples. In clinical trials, oral and intravenous ciprofloxacin yielded similar clinical and bacteriologic results compared to standard therapy in a wide array of systemic infections, including lower and upper urinary tract infections; gonococcal urethritis; skin, skin structure, and bone infections; and respiratory tract and gastrointestinal tract infections. Major benefits with the oral form of this quinolone are expected in chronic pyelonephritis and bone infections, and in pulmonary exacerbations in patients with cystic fibrosis. Emergence of ciprofloxacin-resistant microorganisms has been noted in clinical practice, primarily Pseudomonas aeruginosa and Staphylococcus aureus. The most frequent side effects are related to the gastrointestinal tract; but attention should be given to adverse central nervous system effects.

Worldwide clinical data on efficacy and safety of ciprofloxacin

During the clinical trials 8,861 patients have been treated with ciprofloxacin worldwide. 3,822 of the therapeutic courses were valid for analysis of efficacy according to FDA standards. The following dosages were usually administered: UTI: 100 to 500 mg twice daily orally or 100 mg twice daily intravenously; RTI: 250 to 1000 mg twice daily orally or 200 mg twice daily intravenously; septicemia: 200 mg intravenously twice daily; gonorrhea: 250 to 500 mg single tablet orally; all other infections: 500 to 1000 mg twice daily orally or 200 mg twice daily intravenously. Ciprofloxacin was administered to 762 courses of lower RTI, 88 courses of upper RTI, 108 courses of bacteremia, 766 courses of skin structure infection, 142 courses of bone and joint infections, 149 courses of intra-abdominal infections, 33 courses of gastrointestinal infections, 1,633 courses of UTI, 49 courses of pelvic infections, 279 courses of STD, mainly gonorrhea, and three courses of meningitis. The clinical response was resolution in 76%, improvement in 18% and failure in only 6%. Bacteriologic response by all sites evaluable: pathogens were eradicated from 74%, markedly reduced in 2%, persisted in 10%. Relapse occurred in 4% and reinfection was observed in another 6%. The overall response was favourable for 90% of the patients. Drug safety was established on a data base of 8,861 courses worldwide. The following side-effects according to COSTART terminology were observed: digestive 5%, metabolic nutritional 4.6%, central nervous 1.6%, skin 1.4%, hemic and lymphatic 1%, cardiovascular 0.4%, body as a whole 0.4%, urogenital 0.3%, special senses 0.3%, musculo-skeletal 0.1%, respiratory 0.08%. Several courses had more than one reaction. Thus the total incidence of side-effects for the treated patient population was 10.2%. Ciprofloxacin is a highly effective drug and a breakthrough in several areas of medical interest. It is relatively safe and side-effects are usually mild or moderate in intensity and transient.

Ciprofloxacin concentrations in tonsils following single or multiple administrations

Penetration of ciprofloxacin into human tonsils was studied in 20 adult humans undergoing tonsilectomy. Ten patients received a single intravenous infusion of 200 mg ciprofloxacin within 15 min (group A) and 14 patients were treated orally for three days with 500 mg ciprofloxacin b.i.d. prior to a preoperative infusion of 200 mg (group B). Ciprofloxacin concentrations in serum and tonsils were determined microbiologically. Mean ciprofloxacin serum concentrations did not differ significantly between both groups. Similarly, mean distribution ratios between tonsils and serum were not dissimilar, being on average 150% irrespective of whether the drug was administered once or repeatedly. Thus, a significant accumulation of ciprofloxacin was not observed either in the intravascular or in the extravascular space.

Single and multiple dose pharmacokinetics of ciprofloxacin in gynecological tissues

In a prospective pharmacokinetic study the serum and tissue concentrations of ciprofloxacin (Bay O9867), a new carboxyquinolone antimicrobial agent were studied. 22 patients were given 300 mg ciprofloxacin i. v. before the operation (group A), and 19 patients were premedicated with 500 mg ciprofloxacin orally twice daily for three days followed by 300 mg i. v. preoperatively. Tissue samples weighing approximately 2 g were taken from the fallopian tubes, the ovaries, the fundus myometrium and the cervix. Ciprofloxacin concentrations were measured biologically by the cup plate agar diffusion method. Ciprofloxacin concentrations in serum and gynecological tissues were within the same range in both groups. Maximal serum concentrations of 6 and 4 mg/l, respectively, were recorded immediately after infusion. After 2 h serum concentrations ranged from 0.6 to 1.3 mg/l in both groups. At the same time, the tissue concentrations ranged from 0.62 to 3.3 mg/kg, indicating that tissue levels exceed corresponding serum concentrations. On average ciprofloxacin is concentrated in the extravascular space two-fold, as compared to the corresponding serum concentrations. There is no drug accumulation. The tissue concentrations obtained provide a full antibacterial coverage for gynecological infections, since the MIC for the most pathogenic bacteria is less than 1 mg/l.

Comparative in vitro activities of pefloxacin, ofloxacin, enoxacin and ciprofloxacin against 256 clinical isolates

The antibacterial activity of four new fluoroquinolone carboxylic acids, pefloxacin, ofloxacin, enoxacin and ciprofloxacin, against 256 clinical isolates was investigated by means of an agar dilution method. Generally, all quinolones tested had a high activity against Gram-negative bacteria. More than 90% of Enterobacteriaceae strains were inhibited by a quinolone concentration of 0.4 microgram/ml. Also strains usually resistant to conventional beta-lactam antibiotics, and sometimes to third-generation cephalosporins, like Enterobacter spp., Serratia spp, and Yersinia spp. were susceptible to the tested quinolones. Ciprofloxacin was 5 to 25-fold more potent on a weight basis against Enterobacteriaceae than the other quinolones. Neisseria meningitidis, Neisseria gonorrhoeae, and Haemophilus influenzae were extremely susceptible to the new quinolones. Ciprofloxacin was about 10 times more potent against Pseudomonas aeruginosa than the other quinolones, and was the only quinolone that was sufficiently active against all tested P. aeruginosa strains (MIC less than or equal to 0.4 microgram/ml). The activity against Gram-positive bacteria was considerably lower. All the quinolones investigated had an acceptable activity against many of the methicillin-sensitive and methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococci. The majority of the Streptococcus spp. tested was quinolone-resistant, and was Listeria monocytogenes. Generally, it was evident that ciprofloxacin was more potent on a weight basis than the other quinolones, but this difference was counterbalanced by a higher achievable serum concentration for ofloxacin. Some of the investigated fluoroquinolones might constitute valid therapeutical alternatives to beta-lactam antibodies and aminoglycosides in the treatment of serious bacterial infections.

Ciprofloxacin biliary disposition in cholecystectomised patients with special references to HPLC and bioassay data

The biliary disposition of ciprofloxacin was studied in 12 recently cholecystectomised patients during 24 hours following a single oral administration of 500 mg of the drug. Ciprofloxacin was measured in serum, urine, bile and faeces by both high performance liquid chromatography (HPLC) and bioassay. The results were found to be comparable for the concentrations in serum (mean Cmax = 0.97 +/- 0.17 microgram/ml by HPLC and 1.08 +/- 0.19 microgram/ml by bioassay) and in urine (0.6 h: 267 +/- 74 micrograms/ml and 241 +/- 58 micrograms/ml respectively). Higher concentrations were found in bile when measured by bioassay compared with HPLC (peak concentration = 10.3 +/- 3.4 micrograms/ml and 7.5 +/- 2.8 micrograms/ml respectively; p less than 0.02). The total biliary elimination was also significantly higher according to bioassay data (2167 +/- 288 micrograms/ml versus 1587 +/- 222 micrograms/ml; p less than 0.01). This suggests a first pass effect and hepatic biotransformation of ciprofloxacin to one or more active metabolite (s).

Review of the 4-quinolones

Improvements in antimicrobial activity and pharmacokinetics have moved the 4-quinolones into the forefront of antibiotic research. The 4-quinolones are analogues of nalidixic acid, and there are presently at least six agents in this group under investigation in the United States. It is difficult to generalize their clinical usefulness, since these agents exhibit different pharmacokinetic profiles, antimicrobial activity (with varied minimum inhibitory concentrations among similar organisms), and dosage regimens. The 4-quinolones are potential therapeutic alternatives for infections caused by a variety of organisms. They include: Neisseria gonorrhoeae; Pseudomonas aeruginosa; Haemophilus influenzae; Staphylococcus aureus; common enteric pathogens (salmonella, shigella, campylobacter, etc); and intracellular bacteria (legionella, chlamydia, mycobacteria, etc). Clinical efficacy has been demonstrated in urinary tract infections, respiratory tract infections, and sexually transmitted diseases. Future studies will undoubtedly demonstrate effectiveness in numerous additional infectious processes. The purpose of this article is to compare the 4-quinolones in regards to pharmacokinetics and spectrum of activity and review the clinical studies involving these agents.

Single and multiple dose pharmacokinetics of ciprofloxacin

Penetration of ciprofloxacin into nasal secretion was studied in 20 healty volunteers to whom 500 mg oral ciprofloxacin was administered twice daily for eight days. Nasal secretion and blood samples were collected following the 1st and 15th dose and samples assayed microbiologically. Absolute concentrations of ciprofloxacin in serum and nasal secretion as well as kinetic parameters indicate that repeated administration did not result in significantly increased serum or nasal secretions levels although there was a tendency towards slight drug accumulation. The rate of penetration of ciprofloxacin into nasal secretion was 73% following the first oral dose and 90% following the 15th oral dose.

Ciprofloxacin pharmacokinetics in patients with cystic fibrosis

The pharmacokinetics of ciprofloxacin were studied in cystic fibrosis patients and healthy volunteers following oral administration of 500 mg and 1000 mg. Serum kinetics as well as urinary recovery were monitored. As the body weights of cystic fibrosis patients and the healthy volunteers differed significantly, kinetic parameters were calculated on the basis of a constant relative dose in mg/kg body weight. Neither serum kinetics nor urinary recovery differed significantly between the two groups, as indicated by the serum concentration versus time curves ranging from 1.1 to 1.4 mg X h/l, the elimination half-life of 4.4 to 5.1 h and the 24 h urinary recovery which amounted to 35% to 41% of the dose administered. Serum concentrations were linearly proportional to the doses administered. Sputum concentrations were monitored in cystic fibrosis patients. Again, ciprofloxacin sputum levels were linearly proportional to the doses and were within the same range as serum concentrations. Thus, ciprofloxacin kinetics are not altered in cystic fibrosis patients as compared to healthy volunteers.

Tissue distribution of ciprofloxacin following oral and intravenous administration

Ciprofloxacin distribution in muscle, subcutaneous fat and perirenal and perivesical fat was studied following a single i.v. bolus injection of 100 mg or oral administration of 500 mg. Levels in muscle were on average 0.75 mg/kg; diffusion into muscle was rapid, whereas elimination from muscle was slow. Similar peak levels were recorded in fatty tissues. However, penetration into subcutaneous fat in particular may be delayed in individual cases. Following an initial lagphase of up to one hour after i.v. injection, ciprofloxacin distribution was as efficient in these patients as in the others. Tissue levels following oral administration were monitored 12 hours after intake. On average, ciprofloxacin concentrations in serum, muscle and perirenal fat were 0.17 mg/l, 0.20 mg/kg and 0.11 mg/kg, respectively. Thus, ciprofloxacin is distributed effectively throughout the extravascular space following i.v. as well as oral administration.