Amoxycillin in the treatment of chronic non-tuberculous bronchial infections

Amoxycillin in the Treatment of Childhood Pneumonia

Amoxycillin ('Amoxil') a new semi-synthetic penicillin was used in the treatment of pneumonia in 30 children. A very satisfactory clinical cure was effected in all cases on a dosage requirement of 125 mg eight hourly for 5-8 days.

There were no side-effects. In view of its regimen of three times daily dosage, proven efficacy and facility of administration with food it should be usefully recommended for routine out-patient/in-patient therapy of childhood pneumonia.

Prolonged antibiotics for non-cystic fibrosis bronchiectasis in children and adults

BACKGROUND

The vicious cycle hypothesis for bronchiectasis predicts that bacterial colonisation of the respiratory tract perpetuates inflammatory change. This damages the mucociliary escalator, preventing bacterial clearance and allowing persistence of pro-inflammatory mediators. Conventional treatment with physiotherapy and intermittent antibiotics is believed to improve the condition of people with bronchiectasis, although no conclusive data show that these interventions influence the natural history of the condition. Various strategies have been tried to interrupt this cycle of infection and inflammation, including prolonging antibiotic treatment with the goal of allowing the airway mucosa to heal.

OBJECTIVES

To determine the benefits of prolonged antibiotic therapy in the treatment of patients with bronchiectasis.

SEARCH METHODS

We searched the Cochrane Airways Group Trials Register and reference lists of identified articles. Searches were current as of February 2014.

SELECTION CRITERIA

Randomised trials examining the use of prolonged antibiotic therapy (for four or more weeks) in the treatment of bronchiectasis compared with placebo or usual care.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. We contacted study authors to ask for missing information.

MAIN RESULTS

Eighteen trials met the inclusion criteria, randomly assigning a total of 1157 participants. Antibiotics were given for between four weeks and 83 weeks. Limited meta-analysis was possible because of the diversity of outcomes reported in these trials. Based on the number of participants with at least one exacerbation, the meta-analysis showed significant effects in favour of the intervention (odds ratio (OR) 0.31, 95% confidence interval (CI) 0.19 to 0.52; P value < 0.00001), with events occurring in 271 per 1000 people in the intervention arm (95% CI 126 to 385) and in 546 per 1000 in the control population, based on evidence of moderate quality. A non-statistically significant reduction in hospitalisation favoured the use of prolonged antibiotics with a moderate quality grade of supporting evidence (37 per 1000 in the intervention arm (95% CI 13 to 96) and 87 per 1000 in control (OR 0.40, 95% CI 0.14 to 1.11; P value = 0.08). Drug resistance developed in 36 of 220 participants taking antibiotics compared with 10 of 211 participants given placebo or standard therapy (OR 3.48, 95% CI 1.20 to 10.07; P value = 0.02), translating to natural frequencies of 155 per 1000 in the intervention arm (95% CI 59 to 346) and 50 per 1000 in the control arm. The intervention was well tolerated with no overall significant difference in withdrawal between treatment and placebo groups (OR 0.91, 95% CI 0.56 to 1.49). Diarrhoea was commonly reported as an adverse event, particularly with an oral intervention.

AUTHORS' CONCLUSIONS

Available evidence shows benefit associated with use of prolonged antibiotics in the treatment of patients with bronchiectasis, at least halving the odds of exacerbation (with 275 fewer exacerbations per every 1000 people treated in the antibiotic arm compared with the control arm) and hospitalisation (50 fewer hospitalisations per 1000 people in the antibiotic arm compared with the control arm). However, the risk of emerging drug resistance is increased more than threefold. This review is limited by diversity of trials and by evidence of moderate to low quality. Further randomised controlled trials with adequate power and standardised end points are required.

Short courses of antibiotics for children and adults with bronchiectasis

BACKGROUND

Bronchiectasis is an important cause of respiratory morbidity in both developing and developed countries. Antibiotics are considered standard therapy in the treatment of this condition but it is unknown whether short courses (four weeks or less) are efficacious.

OBJECTIVES

To determine whether short courses of antibiotics (i.e. less than or equal to four weeks) for treatment of acute and stable state bronchiectasis, in adults and children, are efficacious when compared to placebo or usual care.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE, EMBASE, OLDMEDLINE, CINAHL, AMED and PsycINFO and handsearching of respiratory journals and meeting abstracts were performed by the Cochrane Airways Group up to February 2011.

SELECTION CRITERIA

Only randomised controlled trials were considered. Adults and children with bronchiectasis (defined clinically or radiologically) were included. Patients with cystic fibrosis were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed the titles, abstracts and citations to assess eligibility for inclusion. Only one study fulfilled the inclusion criteria and thus meta-analysis could not be performed.

MAIN RESULTS

The single eligible study showed a small benefit, when compared to placebo, of four weeks of inhaled antibiotic therapy in adults with bronchiectasis and pseudomonas in their sputum. There were no studies in children and no studies on oral or intravenous antibiotics.

AUTHORS' CONCLUSIONS

There is insufficient evidence in the current literature to make reasonable conclusions about the efficacy of short course antibiotics in the management of adults and children with bronchiectasis. Until further evidence is available, adherence to current treatment guidelines is recommended.

Pharmacokinetics of amoxycillin and the rate of depletion of its residues in pigs

Six pigs were used in a two-period crossover study to investigate the pharmacokinetics of amoxycillin after single intravenous and oral doses of 20 mg/kg bodyweight. Twelve pigs were used to study the residues of the drug in muscle, kidney, liver and fat after they had received daily oral doses of 20 mg/kg amoxycillin for five days. The mean (sd) elimination half life (t1/2beta) and mean residence time of amoxycillin in plasma were 3.38 (0.30) and 3.54 (0.43) hours, respectively, after intravenous administration and 4.13 (0.50) and 4.47 (0.30) hours, respectively, after oral administration. After oral administration, the maximum plasma concentration (Cmax) was 7.37 (0.42) microg/ml and it was reached after 0.97 (0.29) hours. Six days after the last oral dose, the mean concentration of amoxycillin in the pigs' kidneys was 21.38 ng/g and in the liver it was 12.32 ng/g, but no amoxycillin could be detected in fat or muscle; the concentrations of amoxycillin in edible tissues were less than the European Union maximal residue limit of 50 microg/kg.

Penicillins. A current review of their clinical pharmacology and therapeutic use

The penicillins are a large group of bicyclic ring compounds which contain a 4-membered beta-lactam ring (penams) fused to a 5-membered thiazolidine ring. Benzylpenicillin (penicillin G) was the first natural penicillin with potent activity against all Gram-positive pathogens, Gram-negative cocci and some spirochaetes and actinomycetes. For the last 50 years benzylpenicillin has been the mainstay of therapy for serious pneumococcal, streptococcal, meningococcal and gonococcal infections. However, the past decade has seen the emergence of resistance in certain parts of the world, initially among the gonococci, and more recently among the pneumococci and meningococci. Discovery of the 6-aminopenicillinamic acid nucleus has led to considerable manipulation of the basic ring structure, resulting initially in the synthesis of ampicillin, and subsequently the other aminopenicillins, analogues, esters and prodrugs. These drugs have the advantages of improved oral bioavailability and superior activity against Haemophilus influenzae, certain Gram-negative bacilli, salmonellae, enterococci and Listeria monocytogenes, making these agents popular in the treatment of upper and lower respiratory tract infections and urinary tract infections. The increasing spread of bacterial resistance, particularly among Enterobacteriaceae and H. influenzae, has curtailed the usefulness of these drugs in these clinical settings. To counteract this problem, a number of agents combining a penicillin and a beta-lactamase inhibitor (e.g. clavulanic acid, tazobactam and sulbactam) have been developed. These inhibitors have no intrinsic antibacterial activity, but combining them with a penicillin (e.g. amoxicillin/clavulanic acid) confers greater stability to beta-lactamases and hence a broader spectrum of activity. The emergence of penicillinase-producing staphylococci that rendered benzylpenicillin ineffective also stimulated the search for penicillinase-resistant penicillins--methicillin and nafcillin, followed by the acid-stable isoxazolyl penicillins. These agents are now the principle antistaphylococcal treatment. Methicillin-resistant coagulase-negative staphylococci are currently a major cause of hospital sepsis, and are resistant to these latter agents. Enteric Gram-negative bacilli have been the predominant cause of serious hospital infections during the last 30 years. Further manipulation of the penicillin structure has resulted in compounds with broader activity against Gram-negative bacilli, particularly Pseudomonas aeruginosa, while retaining activity against Gram-positive pathogens. The carboxypenicillins were the first step in this direction, but have been largely superseded by the ureidopenicillins. These agents have better activity against P. aeruginosa, and are still effective against Gram-negative and Gram-positive bacteria, including enterococci and anaerobic organisms.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparative clinical and microbiological study of amoxycillin-clavulanic acid and ciprofloxacin in acute purulent exacerbations of chronic bronchitis

In a retrospective study, the clinical and microbiological efficacy of amoxycillin-clavulanic acid and ciprofloxacin were evaluated in outpatients observed within the previous year who were affected by acute purulent exacerbations of chronic bronchitis. Of the 95 patients included in the trial, 50 received amoxycillin 875 mg-clavulanic acid 125 mg 8-hourly for 10 days and 45 received ciprofloxacin 500 mg 12-hourly before meals for 10 days. Of the amoxycillin-clavulanic acid-treated patients, 90% showed clear clinical improvement and in 10% treatment failed. In the ciprofloxacin group, 75.5% of patients showed improvement and in 24.5% treatment failed. All pathogens isolated prior to therapy were susceptible to the antibiotic used for therapy. At the end of treatment, in the amoxycillin-clavulanic acid-treated group, 84% of strains were eradicated and 8% persisted; others were superinfections. In the ciprofloxacin group, 57.7% of strains were eradicated, 26.6% persisted and 15.5% were superinfections. No clinically significant side effects were observed in either group. Overall, amoxycillin-clavulanic acid demonstrated superior clinical and microbiological efficacy to ciprofloxacin, although this might be attributable to the higher proportion of aerobic Gram-negative pathogens in the ciprofloxacin group.

Use of an enzyme-linked immunosorbent assay to assess penetration of amoxicillin into lung secretions

An enzyme-linked immunosorbent assay (ELISA) was developed to measure total amoxicillin concentrations penetrating lung secretions, which were compared with "active" concentrations measured by conventional bioassay. An antibody was raised in rabbits to amoxicillin conjugated to bovine serum albumin and used in a competitive binding ELISA (sensitivity, 10 ng/ml; precision [coefficient of variation], 9%). The measurement of amoxicillin in lung secretions by using the ELISA method was verified by high-performance liquid chromatography. Amoxicillin concentrations were found to be similar in both whole sonicated sputum and sol-phase sputum obtained by ultracentrifugation following single oral doses of 3 g (4.6 mg/liter for sonicated and 4.7 mg/liter for sol-phase preparations) and 250 mg (0.23 mg/liter for both preparations). Eight patients with bronchiectasis received 500 mg of amoxicillin three times daily. On the second day of therapy (4 h after the morning dose), the mean concentration of amoxicillin in sputum was 0.88 mg/liter (standard error of the mean [SEM], 0.11) by ELISA and 0.40 mg/liter (SEM, 0.05) by bioassay, suggesting a significant degree of local inactivation. This difference between total and active amoxicillin levels was found to correlate significantly (r = 0.693; P less than 0.05) with beta-lactamase levels (mean, 29.5 mU/ml; SEM, 9.4). A pharmacokinetic study on day 3 revealed maximum levels in secretions 2 to 4 h after dosing (mean, 1.36 mg/liter; SEM, 0.26). At the end of successful therapy (day 14), total and active levels were lower (mean, 0.48 mg/liter; SEM, 0.11 [total]; mean, 0.21 mg/liter; SEM, 0.06 [active]); this result was associated with a reduction in lung inflammation (decreased serum-derived albumin in the lung secretions). In conclusion, antibiotic penetration is partly dependent on the degree of lung inflammation. The differences observed in total and active levels of amoxicillin and the relationship to beta-lactamase activity in sputum suggest why higher doses of antibiotic may be required to produce a therapeutic response in some patients.

Penetration of lomefloxacin into bronchial secretions following single and multiple oral administration

The bronchial penetration of lomefloxacin, a new difluorinated quinolone, was evaluated in 36 patients who underwent bronchoscopies for diagnostic purposes. Patients were randomized into two groups, with 18 patients (Group I) receiving a single oral dose of 400 mg lomefloxacin and 18 patients (Group II) receiving 400 mg twice daily. Samples of serum and bronchial secretions were collected simultaneously in both groups at 1, 2, or 4 hours after lomefloxacin administration. The results of this study showed that bronchial penetration of lomefloxacin was rapid and yielded high concentrations; the mean bronchial levels of the drug reached 2.78 +/- 3.64 micrograms/mL in Group I 1 hour after the dose, and 2.84 +/- 1.73 micrograms/mL in Group II at the fourth hour. The ratio between bronchial and simultaneous serum concentrations was 89% at the first and second hours after the dose for Group I, and it was 77% 4 hours after oral administration in Group II. In comparing these results to previous reports of lomefloxacin penetration into bronchial mucosa or of concentrations of other new fluoroquinolones into bronchial secretions, it is to be noted that the local concentrations of the newer quinolones are of very similar values, ranging from 2.7 micrograms/mL (ofloxacin) to 4.46 micrograms/mL (pefloxacin). This study confirms that lomefloxacin achieves high tissue concentrations in the respiratory tree; this characteristic, together with lomefloxacin's antibacterial spectrum, indicates promise in the treatment of many respiratory infections.

Effect of bromhexeine on sputum amoxycillin levels in lower respiratory infections

Bromhexeine has been widely used as an adjunct in the management of lower respiratory infections and is useful in altering the physical characteristics of sputum. Its effect on the sputum penetration of an antibiotic has been sparsely studied. The present study highlights the improvement in sputum amoxycillin (amoxy) levels when a combination tablet, amoxy 500 mg plus bromhexeine 8 mg, is administered as compared to plain amoxy 500 mg. Sputum amoxy levels were significantly higher in the combination group (0.674 +/- 0.588 micrograms ml-1) as compared to 0.272 +/- 0.19 micrograms ml-1 in the amoxy group (P = 0.028). The clinical responses assessed by the physician as well as the patient were significantly better in the amoxy plus bromhexeine group as compared to the amoxy group. The radiological and bacteriological responses were similar in both groups. There was no increase in the side-effects due to bromhexeine and, overall, its use can be recommended in the treatment of acute lower respiratory infections.

A double-blind comparison of the effects of cefaclor and amoxycillin on respiratory tract and oropharyngeal flora and clinical response in acute exacerbations of bronchitis

Fifty-one patients admitted to hospital with severe exacerbations of chronic bronchitis entered a double-blind trial of treatment with cefaclor (500 mg tds) compared with amoxycillin (500 mg tds) for 7 days. Twenty-six patients received cefaclor and 25 amoxycillin. Sputum and throat swabs were collected on admission, after 7 days of therapy and at outpatient follow-up, 3 weeks after treatment had finished. Clinical status and spirometry were assessed on admission and at the third, seventh and 28th day. There was no significant difference between the two regimes for clinical outcome, spirometry or numbers of infecting pathogens. Opportunistic colonization with resistant Gram-negative organisms and Candida species was highly prevalent on admission (56%) in both groups, perhaps because of previous antibiotic administration and general debility of the majority of patients. The high prevalence of opportunistic colonizing organisms persisted at follow-up (48%) with a significant excess of new organisms (Enterobacter cloacae, Klebsiella species and Candida species) present in sputum in the amoxycillin-treated patients. Cefaclor may be less damaging to normal flora than amoxycillin with a consequently reduced risk of colonization and superinfection of the respiratory tract with resistant Gram-negative organisms and yeasts.

[Infections of the lower respiratory tract in general practice]

Haemophilus influenzae and Streptococcus pneumoniae are found in 87% of all cases of exacerbated chronic obstructive bronchopulmonary disease. Complications of viral respiratory tract disease are most frequently caused by H. influenzae. Not only encapsulated forms of H. influenzae, but also non-encapsulated strains may be responsible for the onset of pneumonia and acute exacerbations of chronic bronchitis in adults. The most common symptoms of infections with H. influenzae are cough, dyspnoea, increase in purulent sputum and wheezing. A quantitative sputum culture is recommended for diagnosing chronic obstructive bronchopulmonary disease. Acute exacerbations of chronic bronchitis are always treated with antibiotics effective against H. influenzae and pneumococci. As a rule, empirical treatment should suffice in general practice. In the comparison between ampicillin, co-trimoxazole and cefaclor included in the study protocol appended to this report, the latter produced the most favourable results both in the empirical and specific forms of treatment. We would recommend cefaclor as the antibiotic of choice for this disease.

Serum, saliva, and sputum levels of metronidazole in acute exacerbations of chronic bronchitis

We have evaluated the absorption and the penetration of metronidazole into the bronchial secretions and saliva in acute infective exacerbations of chronic bronchitis. Seventeen patients were given 400 mg orally three times daily for seven days and "steady state" levels were measured in serum, saliva, and sputum on the last day of treatment. Mean levels in the three biological fluids were not significantly different. Higher metronidazole levels in sputum tended to occur in patients with higher serum levels. In all but one patient, levels in serum and saliva were well within the therapeutic range. We conclude that this oral regimen results in therapeutic tissue levels in acute exacerbations of chronic bronchitis.

Plasma and sputum erythromycin concentrations in chronic bronchitis

Plasma and sputum concentrations of erythromycin were measured in 10 patients with chronic bronchitis during an eight-day course of a new formulation of erythromycin stearate. The plasma erythromycin levels compared favourably with the minimal inhibitory concentrations for common respiratory pathogens and indicated adequate gastrointestinal absorption when the drug was taken immediately before food. Sputum erythromycin levels were variable and in some patients low or undetectable. Measurable sputum erythromycin levels were approximately 10% of plasma levels with no evidence of accumulation and were of similar order of magnitude to the minimal inhibitory concentrations for common respiratory pathogens except Haemophilus influenzae. There was no correlation between sputum and plasma erythromycin levels. There was a trend for higher erythromycin levels in sputum containing increasing amounts of pus and also when plasma levels increased.

The aminopenicillins: development and comparative properties

In this review we have compared and contrasted the antibacterial and pharmacological properties of the aminopenicillins currently available. It is apparent that there is little hard evidence (except in the case of thphoid fever) that either amoxycillin or the pro-drug esters of ampicillin are significantly more effective than ampicillin itself, despite their better absorption and higher serum levels. However, amoxycillin and the ampicillin pro-drug esters do cause fewer bowel side-effects than ampicillin, which may justify their use despite the extra cost involved. The problem of susceptibility to penicillinases is unlikely to be solved by modification of the aminopenicillin molecule. A more likely solution is administration of these substances with beta-lactamase inhibitors such as clavulanic acid. Trials with such combinations are already under way.

Doxycycline in serum and bronchial secretions

The concentration of doxycycline hydrochloride was measured in serum and bronchial secretions in five patients with chronic bronchitis receiving doxycycline orally in normal therapeutic dosage for seven days (200 mg day 1, 100 mg days 2 to 7). After the loading dose of 200 mg, serum concentrations ranged between 5-40 and 3-45 mug/ml (mean 4-33 mug/ml) at 3 hours, declining to between 2-28 and 1-21 mug/ml (mean 1-71 mug/ml) at 23 hours. The mean serum levels for days 2 to 7 were 2-15, 1-79, and 1-38 at 3, 8, and 23 hours respectively. There was considerable individual variability and a wide range of concentrations of doxycycline in the sputum (0-07 to 2-10 mug/ml, mean 0-34 mug/ml). During the course of treatment there was a progressive increase in sputum levels and sputum/serum concentration ratios. There was no correlation between sputum concentration and degree of purulence. The clinical efficacy of doxycycline does not appear to be related to sputum concentration, although the progressive increase in sputum doxycycline levels may be relevant in preventing recurrence of acute infection when the drug is administered as long-term prophylactic therapy.

Penetration of antimicrobial agents into bronchial secretions

The entry of ampicillin, cephalothin and gentamicin into traceobronchopulmonary secretions/exudates was assessed in 22 patients during 28, episodes of pneumonia or bronchitis. Specimens were collected from the lower respiratory tract via tracheostomies or endotracheal tubes using either the flexible fiberoptic bronchoscope (50 specimens) or an intratracheal catheter (59 specimens). Venous blood was obtained at the same time. The concentrations in the bronchial specimens were less than those in the corresponding serums, amounting to about 10 per cent with ampicillin, 25 per cent with cephalothin and equal to or greater than 40 per cent with gentamicin.

Sputum and serum levels of amoxycillin in chronic bronchial infections

A study of 11 patients suffering from acute exacerbations of chronic bronchial infection, all with purulent (Mp+++) sputum, showed that good penetration of amoxycillin into such sputum occurs. The levels of amoxycillin in sputum doubled proportionally with the oral dose, at least up to dosages of 2 g. High dosages or oral amoxycillin may therefore, be advantageous in the treatment of chronic bronchial infection. In a study of 30 chronic bronchitic patients, whose sputum varied in purulence from mucoid to purulent (Mp+++) the concentration of amoxycillin in sputum containing approximately 50% pus (Mp++) was significantly higher than that in any other degree of purulence. These results indicate that amoxycillin penetrates best into sputum at an intermediate degree of purulence.

Amoxycillin: A review of its antibacterial and pharmacokinietic properties and therapeutic use

Amoxycillin2 is an acid stable semisynthetic penicillin closely related to ampicillin. Unlike pivampicillin and hetacillin, amoxycillin is not converted to ampicillin in the body. The antibacterial spectrum and level of activity of amoxycillin is essentially the same as for ampicillin, and there is complete cross-resistance between the two drugs. After oral administration, amoxycillin is better absorbed than ampicillin. Mean peak serum levels of amoxycillin are generally twice those of ampicillin after an equal dose. The better absorption and penetration into certain body tissues and fluids of amoxycillin and its greater activity against experimental infections in mice, suggest that it might be preferred to ampicillin in the treatment of some infections, but any clear superiority over ampicillin in clinical practice has yet to be demonstrated. However, these properties have enabled amoxycillin to be given at half the dose of ampicillin without loss of therapeutic efficacy, and the princpal side-effects of skin rashes and diarrhoea have tended to be less frequent with amoxycillin than with ampicillin. Other side-effects are essentially similar in nature to those reported with ampicillin.

Sensitivity of Haemophilus influenzae to antibiotics

The use of many different antibiotics to treat chest infection has led us to test the sensitivity of 68 strains of Haemophilus influenzae to 15 different compounds. These included established compounds such as ampicillin and tetracycline and newer agents such as cephalosporins and clindamycin. The minimum inhibitory concentrations of the compounds for H. influenzae were then compared with blood levels attained after the usual dose regimens. There has been a significant increase in tetracycline resistance in the last few years, but all strains were sensitive to ampicillin, chloramphenicol, sulphamethoxazole, and trimethoprim, Several antibiotics were found to be microbiologically unsuitable for treating H. influenzae infections.

Amoxycillin levels in sputum, serum, and saliva

Stewart, Sheila M., Anderson, Isobel M. E., Jones, G. R., and Calder, Margaret A. (1974).Thorax, 29, 110-114. Amoxycillin levels in sputum, serum, and saliva. The levels of amoxycillin in sputum, saliva, and serum from 22 patients were estimated. Fifteen patients had pneumonia and seven had acute exacerbations of chronic bronchitis. The drug was given orally in a dose of 500 mg four times daily.

There was considerable variation in the levels in specimens from different patients. The mean sputum levels two to three hours and six hours after the dose were 0·52 and 0·53 μg/ml respectively. The mean two-hour saliva level was 0·32 μg/ml. The mean serum levels two and six hours after the test dose were 11·0 and 3·5 μg/ml respectively. The higher levels of amoxycillin were usually associated with the presence of more pus in the sputum. The mean levels of amoxycillin at comparable times were significantly greater than those found in a previous study after the same dose of ampicillin.

Clinical response to treatment occurred more rapidly in those patients with sputum levels of 0·25 μg amoxycillin per ml or above than in those with lower levels. The time taken to clear potential pathogens from the sputum was related to the pathogen rather than to the amoxycillin level, Haemophilus influenzae persisting for longer than Streptococcus pneumoniae.