tetracycline and Pain

Tetracyclines are a class of broad-spectrum bacteriostatic antibiotics used to treat many infections, including methicillin-resistant Staphylococcus aureus (MRSA), acne, pelvic inflammatory disease, chlamydial infections, and a host of zoonotic infections. These drugs work by inhibiting protein synthesis in bacterial ribosomes, specifically by disallowing aminoacyl-tRNA molecules from binding to the ribosomal acceptor sites. While rare, tetracycline antibiotics, particularly minocycline and doxycycline, are associated with an increased risk of developing esophageal perforation and pseudotumor cerebri (PTC, or idiopathic intracranial hypertension). Since tetracyclines are a commonly prescribed class of medications, especially in adolescents for acne treatment, it is important for clinicians to appreciate significant side effects that can result in morbidity and mortality. This paper aims to consolidate and to emphasize current research on the association between tetracycline antibiotics and the development of esophageal perforation, and PTC. PTC is a neurological syndrome consisting of increased intracranial pressure, headache, and vision changes without evidence of the contributing source, such as mass lesion, infection, stroke, or malignancy. Esophageal perforation, while rare, can be the result of pill esophagitis. Pill-induced injuries occur when caustic medicinal pills dissolve in the esophagus rather than in the stomach. Most patients experience only self-limited pain (retrosternal burning discomfort, heartburn, dysphagia, or odynophagia), but hemorrhage, stricture, and perforation may occur. Tetracycline use can lead to pill esophagitis. In summary, clinicians should appreciate the potential risks of tetracycline compounds in clinical practice.

Topics: Acne Vulgaris; Adolescent; Anti-Bacterial Agents; Doxycycline; Esophageal Perforation; Esophagitis; Humans; Methicillin-Resistant Staphylococcus aureus; Minocycline; Pain; Pseudotumor Cerebri; Tetracycline

Topics: Animals; Anti-Bacterial Agents; Chloramphenicol; Diagnosis, Differential; Follow-Up Studies; Glucocorticoids; Humans; Hydrocortisone; Odontoblasts; Pain; Prednisolone; Pulpitis; Tetracycline; Triamcinolone

Autologous blood pleurodesis (ABP) is used for the treatment of pneumothorax with a good efficacy. The aim of this study is to determine the efficacy and safety of ABP in the treatment of malignant pleural effusion (MPE).. A prospective study was conducted at Songklanagarind Hospital, Thailand. Symptomatic MPE patients were randomized to receive pleurodesis with either autologous blood or tetracycline. In the ABP group, 100 ml of autologous venous blood was instilled via chest tube followed by 50 ml of sterile normal saline (NSS). In the tetracycline group, 20 ml of 1% lidocaine diluted in 30 ml NSS was instilled followed by 1 g of tetracycline diluted in 100 ml of NSS. The chest tube was clamped for 2 hours, then reconnected to suction and removed. Pleurodesis effectiveness was evaluated according to Paladine's criteria and adverse events were recorded.. A total of 48 symptomatic MPE patients were recruited. Of these, 24 cases were randomized to receive ABP and 24 cases received tetracycline. There was no difference between the two groups in baseline characteristics. The overall success rate of pleurodesis was the same in both the autologous blood group and the tetracycline group (83.4% versus 87.5%, p = 0.36). In the ABP group, the pain score and fever were significantly lower (8.3% versus 29.1%, p = 0.003) and there was a small percentage of cases that needed analgesia (4.2% versus 75%, p < 0.001); no serious events occurred.. ABP was as effective as tetracycline in the treatment of MPE. ABP produced less pain and fever, and could shorten the hospital stay.

Topics: Aged; Autografts; Blood; Female; Fever; Humans; Length of Stay; Male; Middle Aged; Pain; Pleural Effusion, Malignant; Pleurodesis; Prospective Studies; Sclerosing Solutions; Tetracycline; Thailand; Time Factors; Treatment Outcome

Randomised trials have shown that duodenal ulcers treated by H2 blockers heal faster if Helicobacter pylori is eradicated concurrently. It remains unknown whether eradication of H pylori without suppression of acid-secretion, is sufficient to allow healing. 153 patients with H pylori infection and duodenal ulcer were randomised to receive either a 1-week course of bismuth subcitrate, tetracycline, and metronidazole (76), or omeprazole for 4 weeks with the same three-drug regimen for the first week (77). Endoscopy and antral biopsies were done at entry and 4 weeks after treatment. 132 patients were suitable for analysis. Duodenal ulcers healed in 60 (92%; 95% CI 86-100%) patients taking bismuth, tetracycline, and metronidazole compared with 63 (95%; 88-100%) taking omeprazole in addition to the three other drugs. H pylori was eradicated in 61 (94%; 88-100%) who received only three drugs compared with 66 (98%; 96-100%) who received omeprazole as well. Symptoms were reduced more effectively during the first week in patients who received omeprazole (p = 0.003). We conclude that a 1-week regimen of bismuth, tetracycline, and metronidazole for patients with H pylori and duodenal ulcer eradicates the organism and heals the ulcer in most patients. Concurrent administration of omeprazole reduces ulcer pain more rapidly but has no effect on ulcer healing.

Topics: Adult; Aged; Antacids; Biopsy; Drug Resistance, Microbial; Drug Therapy, Combination; Duodenal Ulcer; Endoscopy, Gastrointestinal; Female; Helicobacter Infections; Helicobacter pylori; Humans; Male; Metronidazole; Middle Aged; Omeprazole; Organometallic Compounds; Pain; Stomach Diseases; Tetracycline; Wound Healing

Annually, approximately 100 of the 400 postmastectomy patients we studied have persisting serous drainage. Sclerotherapy with the use of tetracycline has been advocated to decrease serous drainage and the formation of seromas. Reports in the literature suggest that the use of tetracycline for treatment has been efficacious and that it is not painful. We devised a prospective, randomized controlled trial to study the effects of tetracycline on patients with prolonged persisting drainage. Six patients in the control group had the drains left in place until the drainage diminished. One of these patients had a seroma develop after the drains were removed. Eight patients were treated with tetracycline. Four of these patients had seromas develop after the drains were removed. Three of the eight patients had severe reactions of pain when the tetracycline was introduced into the drains. Because of the severe pain associated with sclerotherapy treatment and the lack of demonstrable benefit in those treated, we terminated the study. We did not find tetracycline to be of help in treating patients with prolonged drainage after mastectomy and some of those patients had severe pain develop from the treatment.

Topics: Drainage; Female; Humans; Mastectomy; Pain; Postoperative Complications; Prospective Studies; Random Allocation; Sclerosing Solutions; Suction; Tetracycline

Topics: Adolescent; Adult; Ampicillin; Chloramphenicol; Clinical Trials as Topic; Dehydration; Drug Combinations; Dysentery, Bacillary; Female; Fever; Humans; Male; Melena; Microbial Sensitivity Tests; Middle Aged; Pain; Shigella; Shigella boydii; Shigella dysenteriae; Shigella flexneri; Streptomycin; Sulfamethazine; Sulfamethoxazole; Tetracycline; Trimethoprim; Vomiting

Topics: Female; Follow-Up Studies; Gonorrhea; Humans; Kenya; Length of Stay; Male; Neisseria gonorrhoeae; Oxyphenbutazone; Pain; Pelvic Inflammatory Disease; Placebos; Tetracycline; Urethra; Uterine Cervical Diseases

Topics: Abdomen; Aged; Bronchitis; Chloramphenicol; Clinical Trials as Topic; Humans; Middle Aged; Nausea; Pain; Suppuration; Tetracycline; Time Factors; Vomiting

Operating time for idiopathic hydroceles and epididymal cysts is scarce as these conditions compete with an increasing caseload of more consequential surgical disease. Therapy is often relegated to repeated aspiration. Sclerotherapy appears to be effective in a majority of published trials, but comparative effectiveness, efficacy and safety of most agents, including phenol versus tetracycline, has not been established A deliberate strategy of re-treatment until cure is not universally practised, with surgery still being offered after single-treatment failures. Two trials, the first consisting of 53 scrotal cysts treated with 5% phenol-in-water and the second, 42 cysts treated with tetracycline, are compared for effectiveness, efficacy and safety of sclerotherapy per se and of re-treatment. Intention-to-treat analysis yields similar cure rates (no re-accumulation three months after last injection) for phenol and tetracycline (83% and 81% respectively, p = 0.8). Per-protocol analysis also yields similar cure rates (100% and 97% respectively, p = 0.26) and mean number of injections to cure (1.34 and 1.12 respectively, p = 0.069), with range 1-4 and 1-3 respectively. Severe pain following tetracycline injection required administration of pre-injection cord block. Other complications occurred equally (25% and 25.7% respectively, p = 0.94) and were trivial except for one case of chronic haematocele treated by orchiectomy in the tetracycline group. Phenol (5%) and tetracycline are equally efficacious sclerosants for idiopathic scrotal cysts, achieving almost 100% cure with re-treatment and matching the efficacy of surgery. Concern about post-treatment fertility applies equally to surgery and demands informed consent for both modalities.

Topics: Humans; Male; Pain; Phenol; Sclerosing Solutions; Sclerotherapy; Spermatocele; Testicular Hydrocele; Tetracycline

Poly(ortho esters) with a low glass transition temperature are semi-solid materials so that therapeutic agents can be incorporated at room temperature, without the use of solvents, by a simple mixing procedure. When molecular weights are limited to < 5 kDa, such materials are directly injectable using a needle size no larger than 22 gauge. Somewhat hydrophilic polymers can be produced by using the diketene acetal 3,9-diethylidene-2,4,8,10-tetraoxaspiro[5.5]undecane and triethylene glycol (TEG), while hydrophobic materials can be produced by using the diketene acetal and 1,10-decanediol. Molecular weight can be reproducibly controlled by using an excess of the diol, or by use of an alcohol that acts as a chain-stopper. Erosion rates can be controlled by varying the amount of latent acid incorporated into the polymer backbone. Toxicology studies using the TEG polymer have been completed and have shown that the polymer is non-toxic. Toxicology studies using the decanediol polymer are underway. Development studies using the TEG polymer aimed at providing a sustained delivery of an analgesic agent to control post-surgical pain are under development and human clinical trials using the decanediol polymer for the treatment of periodontitis are also underway.

Topics: Anesthetics, Local; Animals; Biocompatible Materials; Bupivacaine; Dogs; Drug Carriers; Fatty Alcohols; Gingiva; Glass; Humans; Injections; Magnetic Resonance Spectroscopy; Models, Chemical; Pain; Periodontal Diseases; Polyesters; Polyethylene Glycols; Polymers; Rats; Rats, Sprague-Dawley; Solvents; Temperature; Tetracycline; Time Factors

A renewable source of human sensory neurons would greatly facilitate basic research and drug development. We had established previously conditionally immortalized human CNS cell lines that can differentiate into functional neurons (). We report here the development of an immortalized human dorsal root ganglion (DRG) clonal cell line, HD10.6, with a tetracycline-regulatable v-myc oncogene. In the proliferative condition, HD10.6 cells have a doubling time of 1.2 d and exhibit a neuronal precursor morphology. After differentiation of clone HD10.6 for 7 d in the presence of tetracycline, v-myc expression was suppressed, and >50% of the cells exhibited typical neuronal morphology, stained positively for neuronal cytoskeletal markers, and fired action potentials in response to current injection. Furthermore, this cell line was fate-restricted to a neuronal phenotype; even in culture conditions that promote Schwann cell or smooth muscle differentiation of neural crest stem cells, HD10.6 differentiated exclusively into neurons. Moreover, differentiated HD10.6 cells expressed sensory neuron-associated transcription factors and exhibited capsaicin sensitivity. Taken together, these data indicate that we have established an immortalized human DRG cell line that can differentiate into sensory neurons with nociceptive properties. The cell line HD10.6 represents the first example of a human sensory neuronal line and will be valuable for basic research, as well as for the discovery of novel drug targets and clinical candidates.

Topics: Action Potentials; Capsaicin; Cations; Cell Differentiation; Cell Line; Cell Lineage; Cell Size; Clone Cells; Ganglia, Spinal; Genes, myc; Humans; Ion Channel Gating; Ligands; Neurons, Afferent; Nociceptors; Pain; Stem Cells; Tetracycline; Transcription Factors

Topics: Anti-Bacterial Agents; Drug Eruptions; Female; Humans; Knee; Middle Aged; Pain; Skin Diseases; Tetracycline

The management of malignant pericardial effusion remains controversial. We present our experience with 93 patients referred for drainage and sclerosing procedures between 1979 and 1994.. With continuous electrocardiographic monitoring, a Kifa catheter was inserted percutaneously into the pericardial sac and allowed to drain. A 100 mg dose of lidocaine hydrochloride was instilled intrapericardially, followed by 500 to 1000 mg tetracycline or doxycycline hydrochloride in 20 to 50 ml normal saline solution. The catheter was clamped for 1 to 2 hours and then reopened, and the procedure was repeated daily until the net drainage was less than 25 ml in 24 hours.. Subjects included 53 women and 40 men (median age 58 years). Eight patients could not undergo sclerosis because of technical failure. Eighty-five patients underwent sclerosis and required a median dose of 1500 mg of the sclerosing agent (range 500 to 700 mg), given in a median of three injections (range one to eight). Complications included pain (17 patients), atrial arrhythmias (eight patients), fever with temperature greater than 38.5 degrees C (seven patients), and infection (one patient). Two patients had cardiac arrest before sclerosis could be attempted. Sixty-eight patients (73%) had the effusion controlled for longer than 30 days, for an overall control rate of 81%. Seven other patients had control of the effusion but died of progressive malignant disease in less than 30 days. The overall median survival was 98 days (range 1 to 1724 days). Comparison of these results with outcomes reported for patients with malignant pericardial effusion who underwent surgical drainage indicates that drainage and sclerosis provide similar survivals but sclerosis carries lower morbidity, mortality, and recurrence rates.. Percutaneous drainage and sclerosis constitutes a safe and effective treatment for malignant pericardial effusion. Surgical management should be reserved for the small percentage of cases that cannot be controlled by this method.

Topics: Adult; Aged; Anesthetics, Local; Anti-Bacterial Agents; Arrhythmias, Cardiac; Bacterial Infections; Breast Neoplasms; Cardiac Tamponade; Catheterization; Doxycycline; Drainage; Electrocardiography, Ambulatory; Female; Fever; Follow-Up Studies; Heart Arrest; Humans; Lidocaine; Lung Neoplasms; Male; Middle Aged; Pain; Pericardial Effusion; Pericardium; Sclerosing Solutions; Survival Rate; Tetracycline; Treatment Outcome

Acne fulminans is an ulcerative form of acne with an acute onset and systemic symptoms. It most commonly affects adolescent boys.. Clinical and laboratory findings and treatment results of patients with acne fulminans were reviewed to obtain a better understanding of the clinical course and outcome of the disease.. Data of patients with severe acne were collected from the Dermatology Departments of Finnish hospitals during the years 1970 to 1991.. Twenty-four patients with acne fulminans are described. All patients had ulcerative acne with acute onset. In 22 patients acne was associated with high fever for at least 1 week. All patients had musculoskeletal pain. Increased uptake in bone scan or radiographic findings compatible with an infectious origin were detected in 17 patients. Eight patients were treated with antibiotics alone, but the response was poor; three patients had a relapse of musculoskeletal symptoms. Ten patients were given systemic steroids in addition to antibiotics. In this group the response was rapid, but acne and musculoskeletal symptoms tended to relapse when the steroid dosage was reduced. Four patients were treated with a combination of antibiotics, systemic steroids, and isotretinoin; all responded well, but one of these patients also had a relapse.. Musculoskeletal symptoms are common in patients with acne fulminans. Systemic steroid treatment rapidly controls the skin lesions and systemic symptoms. The duration of steroid treatment should be 2 to 4 months to avoid relapses. Therapy with isotretinoin, antibiotics, or both was often combined with steroids, but the role of these agents is still uncertain.

Topics: Acne Vulgaris; Adolescent; Adult; Anti-Bacterial Agents; Anti-Inflammatory Agents, Non-Steroidal; Blood Sedimentation; Dermatitis, Atopic; Female; Fever; Glucocorticoids; Humans; Isotretinoin; Joints; Leukocytosis; Male; Muscles; Osteolysis; Pain; Retrospective Studies; Tetracycline; Ulcer

A total of 17 patients with hydroceles following renal transplantation underwent sclerotherapy with tetracycline hydrochloride (10 ml. of a 5% solution of tetracycline in 1% lidocaine). A successful outcome was obtained in 15 patients (88%). Post-sclerotherapy hydrocelectomy was necessary in 2 patients (12%). No major complications (testicular loss, scrotal abscess or necrosis) occurred in any patient. Pain at injection was the only adverse effect. Tetracycline sclerotherapy for hydroceles appears to be an effective and safe procedure in the renal transplant population. We recommend this procedure as the initial treatment modality for hydroceles in patients with a renal allograft.

Topics: Adult; Aged; Follow-Up Studies; Humans; Kidney Transplantation; Male; Middle Aged; Pain; Sclerotherapy; Testicular Hydrocele; Tetracycline; Treatment Outcome

40 patients were treated by aspiration and instillation of a 10% solution of tetracycline. 32 were cured after average 1.45 instillations. The dominating adverse effect was scrotal pain, reported by 55% of the patients. One patient experienced a transient vasovagal reaction due to the pain, and one patient was suspected of having a slight infection. No other adverse effect was registered, and 90% of the patients would prefer to have the same treatment rather than an operation if another treatment were found necessary. The treatment is given as an outpatient procedure at 1/10 of the cost of traditional operative treatment, and with comparable results.

Topics: Adult; Aged; Humans; Male; Middle Aged; Pain; Recurrence; Sclerosing Solutions; Scrotum; Spermatocele; Testicular Hydrocele; Tetracycline

Aspiration and tetracycline (Achromycin) instillation has been used to sclerose 'scrotal cysts'. Thirteen hydroceles and epididymal cysts were treated. Of the cysts treated, four failed to sclerose, and moderate to severe pain occurred in eight patients. In three patients the pain was severe, necessitating admission to the hospital. We would not recommend this treatment either in terms of efficacy or for patient comfort.

Topics: Adult; Aged; Ambulatory Care; Cysts; Epididymis; Evaluation Studies as Topic; Humans; Male; Middle Aged; Pain; Sclerotherapy; Testicular Diseases; Testicular Hydrocele; Tetracycline

Fifteen patients with primary hydrocele of the testis were treated by aspiration and injection of tetracycline. Only 5 patients (33.3%) were cured by a single injection of tetracycline. Furthermore, 46.6% of our patients experienced severe scrotal pain, three of whom required open surgery. We do not recommend single injection tetracycline therapy, and further injections were not performed due to severe side effects.

Topics: Adult; Humans; Male; Middle Aged; Pain; Prospective Studies; Sclerotherapy; Testicular Hydrocele; Tetracycline

Successful use of nonnarcotic, thoracic epidural analgesia for the control of pain associated with pleural sclerosis was accomplished in three gynecologic oncology patients with severe respiratory compromise due to malignant pleural effusions. Excellent analgesia was obtained with no observed anesthetic complications.

Topics: Adult; Analgesia, Epidural; Bupivacaine; Catheters, Indwelling; Drug Combinations; Epinephrine; Female; Humans; Middle Aged; Pain; Pleural Effusion; Sclerosing Solutions; Tetracycline

Topics: Cysts; Female; Humans; Pain; Sclerosing Solutions; Tetracycline; Thyroid Diseases

Eikenella corrodens is a gram-negative, facultative anaerobe that exists as part of the normal oral flora. Its role as a pathogen in human infection has been disputed, but recently its pathogenic potential has been increasingly recognized. A review of the literature reveals the emergence of this organism as a pathogen in human infection. Specific microbiologic characteristics of this organism make it difficult to isolate and evaluate for antibiotic sensitivities. Infections produced by this bacteria are characteristically indolent in nature and are usually associated with oral contamination. Appropriate antibiotic therapy utilizes ampicillin or penicillin. Tetracycline is the drug of choice in the penicillin-allergic patient. Clindamycin resistance is a universal feature. A greater awareness of the pathogenic potential of E corrodens is essential for appropriate recognition and treatment.

Topics: Administration, Oral; Adolescent; Ampicillin; Bacteroides Infections; Clindamycin; Eikenella corrodens; Head; Humans; Male; Neck; Pain; Penicillin Resistance; Tetracycline; Time Factors; Wounds, Gunshot

A study of sclerotherapy for hydrocele using different concentrations (10%, 5%, 2.5%) for tetracycline solution was done on 24 patients, 23 patients were cured. The effectiveness of sclerotherapy was the same for the three groups of patients with use of each different concentration of the solution. Pain was the only adverse effect. Nonspecific cellular foreign body reaction and fibrin strand proliferation were observed in the hydrocele fluid after this procedure. We consider sclerotherapy for hydrocele with tetracycline solution safe and the procedure of choice for patients in whom surgery or anesthesia is contraindicated, for patients who refuse surgery, and for economic reasons.

Topics: Evaluation Studies as Topic; Humans; Male; Pain; Sclerosing Solutions; Testicular Hydrocele; Tetracycline

Out of 8 patients with Whipple's disease, 7 had roentgenographic findings consisting of slight dilatation of the small bowel, with thickening of the mucosal folds. The eighth patient had no abnormality on roentgenographic study. This series represents the first in which the roentgenographic changes have been quantitatively assessed. Confirmation of the diagnosis by biopsy is important because antibiotic treatment results in marked improvement both clinically and roentgenographically.

Topics: Adult; Aged; Amenorrhea; Biopsy; Body Weight; Diagnosis, Differential; Diarrhea; Duodenum; Edema; Female; Fever; Follow-Up Studies; Humans; Intestinal Mucosa; Intestine, Small; Jejunum; Joint Diseases; Lymphadenitis; Male; Middle Aged; Pain; Pigmentation Disorders; Purpura; Radiography; Tetracycline; Whipple Disease

A patient is described with features of a superior orbital fissure (Tolosa Hunt) syndrome and a coexistent intraorbital lesion. There was radiological evidence both of narrowing of the carotid artery and of an intraorbital obstruction of venous return from the orbit. The diagnostic value of orbital venography and carotid angiography in the investigation of granulomata in the region of the orbit is stressed. The condition described here is responsive to corticosteroids and it is also inferred that there may be a clinicopathological spectrum encompassing both the Tolosa Hunt syndrome and pseudotumour of the orbit.

Topics: Adult; Carotid Artery Diseases; Cerebral Angiography; Dexamethasone; Humans; Male; Ophthalmoplegia; Orbit; Pain; Tetracycline; Visual Acuity; Visual Fields

Topics: Acute Disease; Adult; Fever; Humans; Lung; Male; Mycoplasma Infections; Pain; Penicillin G; Pleural Effusion; Pleuropneumonia; Radiography; Tetracycline; Transients and Migrants

Topics: Anesthesia, Dental; Child; Dysautonomia, Familial; Female; Humans; Malocclusion; Oral Manifestations; Pain; Pediatric Dentistry; Salivation; Surgery, Oral; Tetracycline; Tooth Discoloration

Topics: Acute Disease; Adult; Amebiasis; Biopsy; Chloroquine; Complement Fixation Tests; Diarrhea; Dysentery, Amebic; Humans; Iodoquinol; Liver; Male; Military Medicine; Pain; Tetracycline; United States; Vietnam

Topics: Anemia; Anemia, Macrocytic; Anemia, Megaloblastic; Celiac Disease; Diverticulum; Drug Therapy; Geriatrics; Humans; Intestinal Diseases; Intestine, Small; Intestines; Pain; Steatorrhea; Tetracycline; Toxicology; Vitamin B 12

In Canada, about 100 sporadically occurring cases of brucellosis are reported yearly. Three patients were admitted to one Montreal hospital in the first seven months of 1963; all were employed in or around a packing plant. One had pain and electrocardiographic changes suggestive of Brucella myocarditis; he recovered promptly. Symptoms of neurasthenia and anxiety are common and were observed in two of these three cases. Two had positive blood cultures; the third showed conclusive agglutination to Br. abortus (1:10,240). In some patients with frequent previous exposures to infection the agglutination response may be equivocal and difficult to interpret. All three patients responded well to tetracycline; streptomycin and corticosteroids also have a role in the therapy of some cases. There may also be some place for combined antibiotic and vaccine therapy. The program of control of the disease in cattle in Canada is aimed at eradication by 1967.

Topics: Animals; Anti-Bacterial Agents; Antigen-Antibody Reactions; Aspartate Aminotransferases; Brucella; Brucella abortus; Brucellosis; Canada; Cattle; Demeclocycline; Drug Therapy; Electrocardiography; Epidemiology; Hospitals, Veterans; Humans; Male; Meat-Packing Industry; Myocarditis; Occupational Diseases; Pain; Streptomycin; Tetracycline; United States; Veterans; Zoonoses

Topics: Ammonia; Ammonium Chloride; Ammonium Compounds; Animals; Characidae; Dermatologic Agents; Ethyl Chloride; Pain; Pain Threshold; Quaternary Ammonium Compounds; Tetracycline