Acute and subchronic neuromuscular blocking characteristics of streptomycin: a comparison with neomycin

Complications associated with antibiotic administration: neurological adverse events and interference with antiepileptic drugs

Antibiotic use is associated with toxic effects involving the peripheral and central nervous systems and it may interfere with antiepileptic drugs, causing significant variations in their serum levels and activity. Prompt identification of neurological complications during antibiotic therapy is important in order to make appropriate modifications to medication. Characteristics of the drug and the patient, including age and underlying diseases, may favour these complications. The main aim of this study was to review the neurological adverse events that may follow antibiotic administration, the mechanisms that cause them, and the possibility of prevention and treatment. Moreover, the interference of antibiotics with serum levels and the activity of antiepileptic drugs are discussed. The results demonstrate that antibiotic-associated adverse events involving the nervous system are relatively uncommon and are only rarely severe and irreversible, although neurotoxicity has been reported for several antibiotics. Moreover, for patients receiving antiepileptic drugs, monitoring of drug serum levels to avoid the risk of toxicity or inadequate therapy is mandatory during antibiotic treatment. Areas for future research include the effects of combined antibiotic therapies as well as multiple antiepileptic drugs in study populations with an adequate sample size, including neonates and infants, patients with pharmacoresistant epilepsy and elderly patients.

Nonantimicrobial Effects of Antibacterial Agents

One of the major advances in modern medicine was the development of antimicrobial chemotherapy. However, many antibacterial agents have unexpected or undesirable nonantimicrobial effects on humans. Microbes and man share many essentials of life, including DNA, adenosine triphosphate, and other biochemical pathways. Hence, some of these nonantimicrobial effects may also turn out to be pharmacologically useful. Oral hypoglycemic agents (i.e., sulfonylureas) and a certain diuretic agent (acetazolamide) are derivatives of sulfonamides. Erythromycin has been used clinically for its stimulatory effect on gastrointestinal motility. Macrolides, lincosamides, and tetracyclines have been known for their immunomodulatory effects. A tetracycline has been used to treat the syndrome of inappropriate antidiuretic hormone. Aminoglycosides may influence mucus production in patients with cystic fibrosis. Other antimicrobials may have side effects that are not therapeutically useful, such as osmotic diuresis with high-dose beta -lactam administration, neuromuscular blockade of aminoglycosides, dysglycemia of fluoroquinolones, and serotonin syndrome with oxazolidinones.

Failure of neuromuscular blockade reversal after rocuronium in a patient who received oral neomycin

PURPOSE

Because the aminoglycoside antibiotics and nondepolarizing muscle relaxants have interactions that vary, it is necessary to update the potential for such interactions when new drugs are introduced clinically. Rocuronium is a newly released steroidal nondepolarizing muscle relaxant with an intermediate duration of action. The following report is the first description of prolonged neuromuscular blockage after rocuronium in a patient who had received oral neomycin in anticipation of open bowel resection.

CLINICAL FEATURES

A 71-yr-old woman with a two week history of bleeding pr was scheduled for exploratory laparotomy and right hemicolectomy. She received two standard bowel preparations consisting of oral erythromycin and neomycin over a two day period. Rocuronium was used to facilitate tracheal intubation and maintain muscle relaxation during a two hour operation. Despite clinical appearance of reversal of neuromuscular blockade after neostigmine and glycopyrolate, the patient complained of dyspnoea and weakness upon tracheal extubation and required reintubation twice. The reason for prolonged muscle relaxation was thought to be secondary to a rocuronium and neomycin interaction.

CONCLUSION

Rocuronium, a new nondepolarizing muscle relaxant, has potential interactions with other drugs including the aminoglycoside antibiotics. This clinical report describes the failure of neuromuscular blockade reversal in a patient who received oral neomycin in anticipation of open bowel resection.

Effects of aminoglycoside antibiotics on cholinergic autonomic nervous transmission

The effects of eight aminoglycoside antibiotics, gentamicin, neomycin B, ribostamycin, dibekacin B, kanamycin A, streptomycin, tobramycin and amikacin, and two non-aminoglycoside antibiotics, tetracycline and ampicillin, on cholinergic autonomic nervous transmission were studied using isolated guinea-pig ileum preparation. The aminoglycoside antibiotics blocked the transmurally elicited twitches of the ileum in a concentration-dependent manner. The blocking effect of aminoglycosides was biphasic, i.e., an initial reduction followed by a spontaneous partial recovery. Dibekacin was the most potent parasympathetic inhibitor, followed by neomycin B, tetracycline, gentamicin, streptomycin, kanamycin A, tobramycin, ribostamycin, and amikacin. Ampicillin had no blocking effect. The tested antibiotics did not affect acetylcholine (ACh)-induced contraction of the ileum, except for high concentrations of neomycin B, gentamicin, and streptomycin. The three antibiotics shifted the dose-response curves for ACh to the right without affecting the maximal contraction. Naloxon, yohimbine, hexamethonium and choline chloride failed to eliminate the blocking effect of the antibiotics on twitches of the ileum induced by transmural stimulation. However, increase of the extracellular Ca ion concentration virtually abolished the blockade. Dibekacin blocked the evoked but not the spontaneous release of ACh and shifted the dose-response curve of CaCl2-dependent transmurally elicited contractions of the ileum to the right. These results suggest that the site for the block of aminoglycosides is mainly the cholinergic nerve terminal, where they reduce the available Ca ions required for the release of ACh.

Aminoglycoside antibiotics block voltage-dependent calcium channels in intact vertebrate nerve terminals

Intrinsic and extrinsic optical signals recorded from the intact nerve terminals of vertebrate neurohypophyses were used to investigate the anatomical site and physiological mechanism of the antagonistic effects of aminoglycoside antibiotics on neurotransmission. Aminoglycoside antibiotics blocked the intrinsic light scattering signal closely associated with neurosecretion in the mouse neurohypophysis in a concentration-dependent manner with an IC50 of approximately 60 microM and the block was relieved by increasing [Ca2+]o. The rank order potency of different aminoglycoside antibiotics for blocking neurosecretion in this preparation was determined to be: neomycin greater than gentamicin = kanamycin greater than streptomycin. Optical recordings of rapid changes in membrane potential using voltage-sensitive dyes revealed that aminoglycoside antibiotics decreased the Ca(2+)-dependent after-hyperpolarization of the normal action potential and both the magnitude and after-hyperpolarization of the regenerative Ca2+ spike. The after-hyperpolarization results from a Ca-activated potassium conductance whose block by aminoglycoside antibiotics was also reversed by increased [Ca2+]o. These studies demonstrate that the capacity of aminoglycoside antibiotics to antagonize neurotransmission can be attributed to the block of Ca channels in the nerve terminal.

Potentiation by gentamicin of non-depolarizing neuromuscular block in the cat

Gentamicin 1-5 mg/kg was injected into 14 anaesthetised cats in the presence of a constant, partial, non-depolarizing neuromuscular block. Twitch response in tibialis anterior was significantly depressed from 83% to 71% of control by a dose of 1.0 mg/kg. In soleus the same dose reduced twitch response from 76% to 71%. After a cumulative dose of 10 mg/kg twitch response in tibialis anterior and soleus was 34% and 37% of control respectively. Calcium chloride 20 mg/kg restored twitch response to 66% in both muscles. Smaller doses of calcium chloride caused partial reversal which was maintained for five minutes in only 50% of instances.