Regimen Of Tetracycline Research Articles

Efficacy and safety of low-dose tetracycline, amoxicillin quadruple therapy in Helicobacter pylori infection: A retrospective single center study.

Helicobacter pylori (H. pylori) eradication rates have declined with the rise of antibiotic-resistant strains in recent years. Although highly effective with a low prevalence of resistance, standard dose tetracycline is associated with frequent adverse events. The efficacy and safety of low-dose tetracycline as part of tetracycline and amoxicillin-containing bismuth quadruple therapy are not well described. To compare the efficacy and safety of low-dose compared to standard dose tetracycline with combined amoxicillin-containing bismuth quadruple therapy in patients with H. pylori infection. Consecutive patients with H. pylori infection receiving tetracycline, amoxicillin, proton pump inhibitor, and bismuth for 14 days at Sir Run Run Shaw Hospital (1/2022-6/2023) were evaluated. The low-dose tetracycline group received tetracycline 500 mg twice daily (bid) while the standard dose group received 750 mg bid or 500 mg three times daily (tid). Primary endpoints were H. pylori eradication rate and treatment-related adverse events. The mean age of the 218 patients was 48.7 ± 14.0 years, 120 (55%) were male, and 118 (54.1%) received treatment as primary therapy. Furthermore, 73 (33%) patients received low-dose tetracycline (500 mg bid) and 145 (67%) received standard dose tetracycline including 500 mg tid in 74 (33%) and 750 mg bid in 71 (33%). On intention-to-treat analysis, H. pylori eradication rates were 89% [95% confidence interval (CI): 82%-96%] in the 500 mg bid group, 82% (95%CI: 74%-91%) in the 500 mg tid group, and 79% (95%CI: 69%-89%) in the 750 mg bid group without a statistically significant difference (P = 0.25). The incidence of adverse events was lower in the low-dose compared to the standard dose group (12.3% vs 31.1% or 23.9%; P = 0.02). Low-dose tetracycline combined with amoxicillin quadruple therapy for 14 days achieved a high eradication rate and fewer adverse events compared to the standard dose tetracycline regimen in patients with H. pylori infection.

S1606 A Retrospective Study of Doxycycline-Based Quadruple Therapy versus Tetracycline-Based Quadruple Therapy for the First Line Treatment of Helicobacter pylori

Introduction: The global prevalence of antimicrobial resistance has resulted in challenges with H. pylori eradication. Gastric acid suppression and antibiotic therapy are used to eradicate H. pylori. Cost and shortages inhibit use of tetracycline for first line treatment of H. pylori. Doxycycline represents a possible cost-effective alternative for treating H. pylori. We performed an analysis of first line doxycycline-based quadruple therapy in comparison to tetracycline-based quadruple therapy in the eradication of H. pylori. Methods: A retrospective chart review was conducted using the Advocate Aurora Health database, a multi-hospital community-based system consisting of sixteen hospitals and over 500 sites of care. All patients age 18 and older with documented H. pylori infection treated with either a first line doxycycline-based regimen (DOX) or tetracycline-based regimen (TCN) from January 2012 to April 2022 were included. In total, 3,384 patients were identified. Patients who received prior first-line treatment with other regimens were excluded. All cases were reviewed for confirmation of infection (either by biopsy, breath test or stool antigen testing), the treatment regimen used, and confirmation of H. Pylori eradication (either by biopsy, breath test, or stool antigen). Patients without confirmation of eradication or with pending eradication test results were excluded. Patient demographics were summarized and eradication rates determined. Results: Of the 3,384 reviewed cases, 628 cases met inclusion and exclusion criteria. Of these, 305 patients were treated with DOX and 323 patients were treated with TCN. Based on these numbers, a posteriori non-inferiority calculation with an assumed 85% eradication rate for the TCN and 80% for DOX and 90% power suggested 100 patents were needed per group (HyLown Consulting LLC, Statistical Calculators). The average age for DOX was 57 years and 193/305 (60%) were female. The average age for TCN was 58.5 years and 210/323 (69%) were female. Eradication rates were 87.6% for DOX and 88.2% for TCN (Table). Conclusion: Doxycycline-based quadruple therapy regimen is effective and appears to be non-inferior to tetracycline-based quadruple therapy regimens for first line treatment of H. pylori. Table 1. - The number of patients with tetracycline or doxycycline antibiotic regimens and the eradication rate Doxycycline Regimen # of Patients % of Patients Successful Eradication 283 87.6% Failed Eradication 40 12.4% Total 323 Tetracycline Regimen # of Patients % of Patients Successful Eradication 269 88.2% Failed Eradication 36 11.8% Total 305

Efficacy and safety of bismuth quadruple regimens containing tetracycline or furazolidone for initial eradication of Helicobacter pylori.

Helicobacter pylori (H pylori) infection can cause chronic gastritis, peptic ulcer, and even gastric cancer, so effective eradication is critical.This study compared the efficacy and safety of bismuth quadruple regimens including either tetracycline or furazolidone for initial eradication.Patients newly diagnosed with H pylori infection from January 2020 to January 2021 were randomly assigned to receive either the tetracycline-containing regimen (n = 116) or furazolidone-containing regimen (n = 168). Both regimens included 1 proton pump inhibitor (rabeprazole 20 mg, or esomeprazole 20 mg, or eprazole 5 mg), colloidal pectin bismuth 300 mg, and amoxicillin 1000 mg in addition to tetracycline 1.0 g or furazolidone 0.1 g. All drugs were administered twice daily for 12 consecutive days. The 14C urea breath test was used for diagnosis, and re-test negativity at one-month follow-up was considered successful eradication. Adverse events were recorded during follow-up by telephone interview.In total, 109 patients in the tetracycline group and 157 in the furazolidone group were re-examined at 1 month. In the tetracycline group, 101 patients tested negative at follow-up, yielding an eradication rate of 92.7% according to per-protocol analysis and 87.1% by intention-to-treat analysis. In the furazolidone group, 141 patients tested negative, yielding eradication rates of 89.8% by PP and 83.9% by ITT. Eradication rates did not differ significantly between regimens (per-protocol: χ2 = 0.637, P = .517; intention-to-treat: χ2 = 0.537, P = .501). However, total adverse events incidence was significantly lower in the tetracycline group (20.2% vs 37.6%; χ2 = 9.193, P = .003).Both bismuth quadruple regimens produce high initial eradication, but the tetracycline regimen appears safer.

Doxycycline and minocycline in Helicobacter pylori treatment: A systematic review and meta-analysis.

The decreasing Helicobacter pylori eradication rate and the increasing antibiotic resistance trend are of great concern. Therefore, new and effective therapies are needed for H.pylori infection. We conducted a systematic review and meta-analysis to assess the efficacy and safety of semisynthetic tetracycline regimens in H.pylori treatment. PubMed, EMBASE, and the Cochrane library were searched. The outcome indicators were the eradication rate, risk ratio (RR, ie, the risk of the semisynthetic tetracycline regimen relative to the control), and 95% confidence interval (95% CI). Controls were patients undergoing any other treatment without semisynthetic tetracycline. Twenty-three studies with 5240 participants were included. The eradication rates of triple regimens with semisynthetic tetracyclines in most studies were less than 70% in both the intention-to-treat (ITT) and the per-protocol (PP) analyses. The pooled eradication rates of quadruple therapies with doxycycline and controls were 95% and 84% in the PP analyses, respectively. The pooled RR associated with efficacy in the quadruple therapy with doxycycline group compared with the control group was 1.12 (95% CI: 1.04-1.20) in the PP analysis. The pooled RR of side effects in the quadruple therapy with doxycycline group compared with the control group was 1.01 (95% CI: 0.65-1.55). Seven-day and ten-day quadruple therapy with doxycycline might be an optional first-line therapy. The safety of regimens containing semisynthetic tetracyclines was relatively satisfactory. However, the triple regimen is not recommended.

Rifaximin Plus Levofloxacin-Based Rescue Regimen for the Eradication of Helicobacter pylori

Background/AimsThis study assessed the efficacy of a rifaximin plus levofloxacin-based rescue regimen in patients that had failed both triple and quadruple standard regimens for the eradication of Helicobacter pylori.MethodsWe treated patients for H. pylori between August 2009 and April 2011. The triple regimen consisted of combined treatment with amoxicillin, clarithromycin, and pantoprazole for 1 week. For failed cases, a quadruple regimen of tetracycline, metronidazole, bismuth dicitrate, and lansoprazole for 1 week was administered. The rescue regimen for persistently refractory cases was rifaximin 200 mg t.i.d., levofloxacin 500 mg q.d., and lansoprazole 15 mg b.i.d. for 1 week.ResultsIn total, 482 patients were enrolled in this study. The eradication rates associated with the first and second regimens were 58% and 60%, respectively. Forty-seven out of 58 patients who failed with the second-line regimen received rifaximin plus levofloxacin-based third-line therapy. The eradication rate for the third regimen was 65%. The cumulative eradication rates were 58%, 85%, and 96% for each regimen, respectively.ConclusionsA rifaximin plus levofloxacin-based regimen could be an alternative rescue therapy in patients with resistance to both triple and quadruple regimens for the eradication of H. pylori.

Effectiveness of different treatment regimens in helicobacter pylori eradication: Ten-year experience of a single institution

We aimed to report the outcomes of different H. pylori eradication regimens used in our institution over the last 10 years. Retrospectively, H. pylori-positive patients who were referred for upper gastrointestinal endoscopy with dyspeptic symptoms and who started eradication treatment and returned for a follow-up visit were included in the study. Subjects were allocated into six groups according to their treatment regimens as follows: Group 1) Proton pump inhibitor, clarithromycin and amoxicillin for 2 weeks; Group 2) Colloidal bismuth subcitrate, metronidazole and tetracycline for 2 weeks; Group 3) ranitidine bismuth citrate, clarithromycin and amoxicillin for 2 weeks; Group 4) Proton pump inhibitor, colloidal bismuth subcitrate, clarithromycin and amoxicillin for 2 weeks; Group 5) Proton pump inhibitor, tetracycline and amoxicillin for 2 weeks; and Group 6) Proton pump inhibitor and amoxicillin for 5 days, followed consecutively by Proton pump inhibitor, clarithromycin and metronidazole for 5 days. A follow-up visit to determine eradication was scheduled a minimum of 6 weeks after completion of the treatment. In this study, 400 patients were included. Eradication rates were 74.7%, 92.3%, 81.2%, 81.5%, 70.5%, and 66.6% in Groups 1-6, respectively. In Group 1, the eradication rate was lower than 80%. In Groups 34, the eradication rate increased to over 80%. The colloidal bismuth subcitrate, metronidazole and tetracycline regimen (Group 2) was the most successful, with a rate of 92.3%. The eradication rate in the consecutive regimen group (Group 6) did not reach the recommended level (higher than 80-85%).

Pylera® for the eradication of Helicobacter pylori infection

An ideal antibiotic regimen for Helicobacter pylori should achieve eradication rates of approximately 90%. Current 7-day triple therapy is successful in about two-thirds of patients. A novel treatment is required to achieve higher eradication with minimal induction of bacterial resistance. The aim of this article is to evaluate the safety and efficacy of a single triple capsule (Pylera®) containing bismuth, metronidazole and tetracycline, given with omeprazole for the eradication of H. pylori infection. Extensive literature searches were conducted using PubMed data from 1982 to 2007. This search included headings of H. pylori, bismuth and eradication therapy. The triple capsule Pylera, when given with omeprazole, achieved eradication rates ranging between 84 and 97%. Eradication rates were similar for clarithromycin- and metronidazole-resistant strains. Eradication rates with an omeprazole, bismuth, metronidazole and tetracycline regimen appeared comparable for metronidazole-resistant and -sensitive strains. This effect is not seen with the use of triple therapy in cases of clarithromycin resistance. Clinical trials did not report any serious side effects from bismuth-based regimens and compliance was similar to standard triple therapy. Bismuth-based triple therapy using Pylera is a simplified, effective and well-tolerated regimen achieving cure rates of above 90%.

The efficacy of ranitidine bismuth citrate, amoxicillin and doxycycline or tetracycline regimens as a first line treatment for Helicobacter pylori eradication

Background The eradication rates of Helicobacter pylori ( H. pylori) clearly decreased with standard PPI-based triple therapies. Aim To assess the efficacy of two different triple therapies consisting of ranitidine bismuth citrate–amoxicillin–doxycycline and ranitidine bismuth citrate–amoxicillin–tetracycline combinations as a first line treatment option. Methods One hundred and fifteen consecutive dyspeptic patients in whom H. pylori infection was diagnosed for the first time were enrolled in this study. The patients were randomized into two groups. Group 1 ( n = 57) was assigned to receive a 14-day triple therapy consisting of ranitidine bismuth citrate 400 mg (b.i.d), amoxicillin 1 g (b.i.d) and doxycycline 100 mg (b.i.d). Group 2 ( n = 58) was assigned to receive a 14-day triple therapy consisting of ranitidine bismuth citrate 400 mg (b.i.d), amoxicillin 1 g (b.i.d) and tetracycline 500 mg (q.i.d). Results The eradication was achieved in 45.7% (21/46) and 40.8% (20/49) of the patients in group 1 and group 2, according to per protocol analysis. The intention-to-treat eradication rates were 36.8% (21/57) and 34.5% (20/58) in group 1 and group 2, respectively. Conclusions Two-week therapy with neither ranitidine bismuth citrate–amoxicillin–doxycycline nor ranitidine bismuth citrate–amoxicillin–tetracycline is adequately effective for H. pylori eradication as a first line therapy.

Commentary

Brucellosis is a zoonosis which in humans is caused by one of four species of the Brucella genus: B. melitensis, B. abortus, B. suis and B. canis. B. abortus is the species prevalent in North America and Europe and B. melitensis in most developing countries.Differences in disease manifestations may be accounted for either by differences in the species or by differences in the host. Articular involvement in brucellosis, although recognized since 1904, has been variably emphasized.Three hundred and four cases of human Brucellosis caused by B. melitensis, the prevalent species in Perú, were seen during a 12-yr period in one Lima hospital. Fever, malaise and hepatomegaly were the most frequent findings. Diagnosis was greatly improved when cultures were done in the biphasic Ruiz-Castañeda medium, rather than in trypticase soy broth. Serologie diagnosis is still important, and it should include standard tube testing, detection of IgG blocking antibodies and fractionation with 2-ME in chronic cases.The disease may take one of three courses: acute, (<8 wk), chronic (>8 wk) or undulant (periods of remissions and exacerbations). Four syndromes were recognized in a total of 33.8% of patients with Brucellosis. The most frequent pattern (in ~46.6% of patients with arthritis) was sacroiliitis, usually non-destructive and either uni-or bilateral. The second most frequent articular syndrome was peripheral arthritis (38.8%), manifested either as a single large lower extremity joint or as an asymmetric pauciarthritis. Rarely patients presented with a rheumatoidlike arthritis. Mixed arthritis (7.8%) was a combination of the first two. The above forms occurred in patients with an acute or undulant course. Spondylitis was the least common form of arthritis (6.8%), and differed significantly from the other forms of arthritis in the duration of symptoms (chronic course), age of patients (older individuals) and the paucity of fever and malaise. It also tended to be destructive.The arthritis usually resolved with the combined regimen of tetracycline (2 g p.o. for 21 days) and streptomycin (1 g i.m. for 21 days) without sequelae. Illustrative cases of these syndromes are presented.The relatively benign nature of most of the patients with brucellar arthritis lead us to postulate that they are for the most part reactive arthritides. Host factors are thought to be important in determining the response to the infection, but they are yet to be identified. Our own genetic studies have failed to identify an increased frequenty of B27 or CREG antigens in the patients with sacroiliitis. The demonstrations of circulating immune complexes in these patients however favors an immunopathogenic mechanism as responsible for some of the manifestations of this disease.

The Clinical Efficacy of Helicobacter pylori Eradication in Patients with Helicobacter pylori-Positive Chronic Thrombocytopenic Purpura.

Background: Helicobacter pylori (H pylori) has been implicated in the pathogenesis of some autoimmune diseases including idiopathic thrombocytopenic purpura (ITP). Several studies recently showed a high prevalence of H pylori infection in patients with ITP and reported a platelet recovery after bacterial eradication therapy. The prevalence of H pylori infection and effect of its eradication in Korea patients with chronic ITP were investigated.Methods: The study included among 35 patients with chronic ITP from eight hospitals. H pylori infection was assessed by urea breath test, rapid urease test or microbial culture. H pylori eradication was performed with amoxicillin, clarithromycin and omeprazol regimen for 7 days or bismuth, metronidazol and tetracycline regimen for 10 days. Eradication was assessed by urea breath test 4 weeks after treatment. Platelet counts were monitored serially after the end of treatment.Results: Thirty five patients with chronic ITP were evaluated, including 12 males and 23 females. Median age was 57 years (range 30–79). The median platelet count before eradication was 23,000/uL (range 4,000–66,000/uL). Sixteen patients were performed the splenectomy previously. H pylori infection was found in 23 (65%) of 35 patients. In 21 patients performed the eradication, 6 patients (28.5%) had a significant increase in platelet count after 2 weeks and 2 months. The response duration was 1–27 (median 7.6) months.Conclusions: This study confirmed the efficacy of H pylori eradication in increasing platelet in adult chronic ITP patients. We must consider the investigation and eradication of H pylori infection in ITP patients as a simple, inexpensive tool in management of the chronic disease.

A Randomized Trial to Compare 7− and 21-Day Tetracycline Regimens in the Prevention of Recurrence of Infection with Chlamydia trachomatis

Standard therapy for Chlamydia trachomatis in the United States consists of a 7-day course of tetracycline administration. Recurrent infections are frequent, however, in circumstances in which reinfection seems unlikely, suggesting that the standard regimen may be insufficient to cure the infection. It may reduce the number of organisms, however, below a detectable level at a test-of-cure visit. To evaluate recurrent infection, the authors studied patients with chlamydia who were treated with standard therapy, and they found a recurrence rate of 29% among 2,983 patients who returned to the clinic during a 2-year follow-up period. Recurrent infection was associated with younger age but was not related to either race or gender. To test the hypothesis that a longer treatment course might be more effective in preventing recurrent infection, the authors conducted a randomized trial that compared 7- and 21-day regimens of tetracycline administration. Of the 918 subjects enrolled in the trial, 220 were infected with C. trachomatis. The overall recurrence rate among patients who were infected and returned was 18.4% (9/49) in the 21-day group and 13.8% (8/58) in the 7-day group (P = .60). Similar results were obtained using survival analysis methods. Given the number of subjects who returned, this study had approximately a 65% statistical power to detect a reduction in recurrence rate, from 20% to 5%. Because of the similarity of the results in the two groups, it was concluded that 21 days of tetracycline administration is no more effective in preventing recurrence than 7 days of administration.

Therapy for nonvenereal treponematoses: review of the efficacy of penicillin and consideration of alternatives.

Penicillin therapy has been a crucial element in public health programs for control of nonvenereal treponematoses. The recommendations made by the World Health Organization on penicillin therapy and the literature substantiating the effectiveness of penicillin therapy are reviewed. In mass public health programs, the recommended penicillin regimen can confidently be used. Although penicillin is the drug of choice for all treponemal infections, some individuals will be allergic to this drug. For these persons tetracyclines are the most thoroughly evaluated alternative antimicrobial agent and seem highly effective. However, further comparative evaluations of various tetracycline regimens are needed if tetracyclines are required by more than the occasional individual. The long-acting tetracyclines may be particularly appropriate in minimizing problems of compliance.

Rifampin therapy for brucellosis, flavobacterium meningitis, and cutaneous leishmaniasis.

Rifampin has a broad antibacterial spectrum. At high concentrations it also is active in vitro against protozoa, i.e., different species of Leishmania. Rifampin has been used against bacterial and occasionally protozoal infections. Addition of rifampin to a tetracycline regimen was found to reduce the number of relapses in patients with acute and chronic brucellosis. In a few cases of meningitis due to Flavobacterium meningosepticum, which failed to respond to other drugs, patients were treated successfully with rifampin administered either orally or intravenously. Rifampin at doses of greater than or equal to 600 mg daily has been administered to patients with cutaneous leishmaniasis. Healing of skin lesions was observed in the majority of treated patients. Controlled studies are needed to assess the usefulness of rifampin in this disease.

Articular involvement in human Brucellosis: A retrospective analysis of 304 cases

Brucellosis is a zoonosis which in humans is caused by one of four species of the Brucella genus: B. melitensis, B. abortus, B. suis and B. canis. B. abortus is the species prevalent in North America and Europe and B. melitensis in most developing countries. Differences in disease manifestations may be accounted for either by differences in the species or by differences in the host. Articular involvement in brucellosis, although recognized since 1904, has been variably emphasized. Three hundred and four cases of human Brucellosis caused by B. melitensis, the prevalent species in Perú, were seen during a 12-yr period in one Lima hospital. Fever, malaise and hepatomegaly were the most frequent findings. Diagnosis was greatly improved when cultures were done in the biphasic Ruiz-Castañeda medium, rather than in trypticase soy broth. Serologie diagnosis is still important, and it should include standard tube testing, detection of IgG blocking antibodies and fractionation with 2-ME in chronic cases. The disease may take one of three courses: acute, (<8 wk), chronic (>8 wk) or undulant (periods of remissions and exacerbations). Four syndromes were recognized in a total of 33.8% of patients with Brucellosis. The most frequent pattern (in ~46.6% of patients with arthritis) was sacroiliitis, usually non-destructive and either uni-or bilateral. The second most frequent articular syndrome was peripheral arthritis (38.8%), manifested either as a single large lower extremity joint or as an asymmetric pauciarthritis. Rarely patients presented with a rheumatoidlike arthritis. Mixed arthritis (7.8%) was a combination of the first two. The above forms occurred in patients with an acute or undulant course. Spondylitis was the least common form of arthritis (6.8%), and differed significantly from the other forms of arthritis in the duration of symptoms (chronic course), age of patients (older individuals) and the paucity of fever and malaise. It also tended to be destructive. The arthritis usually resolved with the combined regimen of tetracycline (2 g p.o. for 21 days) and streptomycin (1 g i.m. for 21 days) without sequelae. Illustrative cases of these syndromes are presented. The relatively benign nature of most of the patients with brucellar arthritis lead us to postulate that they are for the most part reactive arthritides. Host factors are thought to be important in determining the response to the infection, but they are yet to be identified. Our own genetic studies have failed to identify an increased frequenty of B27 or CREG antigens in the patients with sacroiliitis. The demonstrations of circulating immune complexes in these patients however favors an immunopathogenic mechanism as responsible for some of the manifestations of this disease.

Ureaplasma Urealyticum and Infertility: The Effect of Different Antibiotic Regimens on the Semen Quality

Objective criteria of semen quality were evaluated in 243 men treated for Ureaplasma urealyticum genital tract infection with 1 of 4 different antibiotic regimens. Significant improvement was observed in motility, quantity, quality, and percentages of oval and small forms. Doxycycline, whether used for 2 or 4 weeks, at a dosage of 100mg. twice daily resulted in the same cure rate (79 and 81 per cent, respectively). Tetracycline regimens of 500mg. 3 times daily for 2 or 4 weeks had significantly inferior cure rates (17 and 55 per cent, respectively). These findings suggest that antibiotic therapy could be valuable in improving semen quality when Ureaplasma is isolated, and that followup culture for the organism should decide the endpoint in therapy, since resistant strains for doxycycline and tetracycline are emerging.

Influence of dietary restriction and protein deficiency on plasma half-life and tissue distribution of tetracycline in rats.

1. The effects of dietary restriction and protein deficiency on plasma half-life and tissue distribution of tetracycline were studied in rats by feeding either a 20% protein diet in restricted quantity or a 9% protein diet ad lib and compared with rats given a 20% protein diet ad lib (control group). 2. It was observed that half-life of tetracycline was shortened and that plasma and tissue Cmin levels at steady-state were lower in undernourished rats. Tissue concentrations in liver, kidney, muscle and bone correlated well with plasma levels. A high degree of correlation was also observed between plasma and tonsillar concentrations of tetracycline in human subjects. 3. These studies indicate that undernourished subjects may require an altered dosage regimen of tetracycline to maintain effective steady-state concentrations of the drug.

Gonococcal urethritis in males in Vietnam: three penicillin regimens and one tetracycline regimen

Gonococcal urethritis in males in Vietnam: three penicillin regimens and one tetracycline regimen

Studies of Venereal Disease

Previous studies of the treatment of nongonococcal urethritis (NGU) have generally not been closely controlled, and have often produced conflicting results. In the present study, 96 men with NGU were treated with placebo or tetracycline hydrochloride while confined aboard an aircraft carrier at sea. A seven-day tetracycline regimen was more effective than a four-day tetracycline regimen or placebo in the short-term cure of NGU.

Variable sensitivity of assay methods of tetracycline and demethylchlortetracycline in human volunteers.

Evaluation of levels of serum antibacterial activity was attempted in 17 normal subjects who took a therapeutically recommended drug regimen of tetracycline or demethylchlortetracycline for 4 days. Microbiologic assay was performed by the tube dilution method with three separate test organisms, and one of these was used in a parallel cup‐plate assay method. The cup‐plate method was found to be more sensitive and more reliable than the tube dilution methods using any of the three organisms. With the dosage regimens used, serum activity accumulation could be shown for DMCT but not for TC.Although individual subject variability in drug absorption may be noted, the average level of serum antibacterial activity was consistently higher with 150 mg. of DMCT four times daily than with 250 mg. of TC four times daily. After 4 days, the difference was found to be Significantly higher in the cup‐plate method and the tube dilution method when Bacillus cereus was the test organism but not in the tube dilution method when streptococcus 98 or staphylococcus 209P was used.We were unable to demonstrate differences in prolongation of serum activity levels after cessation of therapy with these two drugs.

Long-term therapy of acne with tetracycline.

Long-term antibiotic therapy of acne does not imply that the drugs are slow to produce an effect; actually, the patient may improve quickly, but when their use is stopped the acne relapses. The same is true of dermatitis herpetiformis, which, however, is usually far more chronic than acne. In most series of cases where accepted methods of treatment are used, 50% to 75% of acne patients improve substantially within 6 to 9 months. The rest are more resistant. It is this latter group with which we are here concerned in this paper. The patients in it remained from an original 132 whose therapy was begun with antibiotics. Those not included for further consideration went on to sufficient improvement to permit withdrawal of the antibiotic. Materials and Method All patients were initially given 1,000 mg. tetracycline * (4 capsules) daily, and no other therapy was given once the tetracycline regimen was begun.