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TOBRAMYCIN is a brand name for Tobramycin. The medicine, its uses, side effects and dosage are the same regardless of brand.
Used for: Tobramycin Injection is indicated in the treatment of the following serious infections caused by susceptible micro-organisms: • The treatment of central nervous system infections including meningitis, septicaemia and neonatal sepsis; • The treatment of gastro-intestinal infections including peritonitis; • The…
Verbatim from this product's MHRA label. Tap a section to expand.
Posology Tobramycin Injection may be given intramuscularly or intravenously and the dosage is the same for either route of administration. To calculate the correct dosage, the patient’s pre- treatment body weight should be obtained.
It is recommended that both peak and trough serum levels should be determined whenever possible to ensure the correct dosage is given. Blood levels should always be determined in patients with chronic infections such as cystic fibrosis, or where longer duration of treatment may be necessary, or in patients with decreased renal function.
Duration of treatment The usual length of treatment is seven to ten days. However, in difficult and complicated infections, a longer course of therapy may be necessary. In such cases monitoring of renal, auditory and vestibular functions is advised because neurotoxicity is more likely to occur when treatment is extended longer than ten days.
Patients with normal renal function Adults For adults with serious infections the usual recommended dosage is 3 mg/kg/day, administered in three equal doses every eight hours. (see Table 1). Patients with life-threatening infections, dosages up to 5 mg/kg/day may be administered in three or four equal dosages.
The dosage should be reduced to 3 mg/kg/day as soon as clinically indicated. Dosage should not exceed 5 mg/kg/day, unless serum levels are monitored in order to prevent increased toxicity due to excessive blood levels. 4). It may be necessary to administer up to 8 to 10 mg/kg/day in equally divided doses, to achieve therapeutic serum levels for patients with cystic fibrosis.
Serum levels should be monitored because serum concentrations of tobramycin vary from patient to patient. In adults with normal renal function, mild to moderate infections of the urinary tract have responded to a dosage of 2-3 mg/kg/day administered as a single intramuscular injection.
(see Table 1). Table 1 Dosage schedule for adults with normal renal function (Dosage at 8-hour intervals) Patient Weight Usual dose for Serious Infections 1 mg/kg q 8 h. 66 mg/kg q 8 h. 6 * Applicable to 40 mg/ml product forms. Following IM administration of a single dose of tobramycin of l mg/kg in adults with normal renal function, peak plasma tobramycin concentrations averaging 4-6 micrograms/ml are attained within 30-90 minutes; plasma concentrations of the drug are 1 microgram/ml or less at 8 hours.
The frequency grouping is defined using the following convention:
Very common (≥1/10); Common (≥ 1/100 to <1/10); Uncommon (≥1/1,000 to <1/100); Rare (≥ 1/10,000 to <1/1,000); Very Rare (< 1/10,000); and Not known (cannot be estimated from the available data). Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness.
Blood and lymphatic system disorders Not known Anaemia, granulocytopenia, thrombocytopenia, leucopenia, leucocytosis, eosinophilia Immune system disorders Not known Hypersensitivity Psychiatric disorders: Not known Mental confusion, disorientation Nervous system disorders Not known Dizziness, headache, lethargy Ear and labyrinth disorders1 Not known Hearing loss, tinnitus, vertigo Gastrointestinal disorders: Not known Nausea, vomiting, diarrhea Skin and subcutaneous tissue disorders: Not known Dermatitis exfoliative, rash, itching, urticaria Renal and urinary disorders2 Not known Acute kidney injury, blood creatinine increased, blood urea increased, proteinuria, oliguria, cylindruria General disorders and administration site conditions Not known Fever, pain at injection site Investigations Not known Blood bilirubin increased, aspartate aminotransferase increased, alanine aminotransferase increased, blood calcium decreased, blood magnesium decreased, blood sodium decreased, blood potassium decreased 1 In patients receiving high doses or prolonged therapy, side effects on both vestibular and auditory branches of the eighth cranial nerve have been reported.
Similar effects have been noted in those given previous courses of therapy with an ototoxin, and in cases of dehydration. Symptoms include vertigo, tinnitus, roaring in the ears and hearing loss. Hearing loss is usually irreversible and is manifested initially by diminution of high tone acuity.
2 Renal function changes have been reported, especially in patients with a history of renal impairment who are treated for longer periods or with higher doses than these recommended. These changes can occur in patients with initially normal renal function.
Evidence of impairment in renal, vestibular and/or auditory function requires discontinuation of the drug or dosage adjustment. Ototoxicity Both vestibular and auditory ototoxicity can occur. Eighth nerve impairment may develop in patients with pre-existing renal damage, and if tobramycin is administered for longer periods or in higher doses than those recommended.
Other manifestations of neurotoxicity may include numbness, skin tingling, muscle twitching and convulsions. The risk of aminoglycoside-induced hearing loss increases with the degree of exposure to either high peak or high trough serum concentrations.
Patients with mitochondrial DNA mutations, particularly the nucleotide 1555 A to G substitution in the 12S rRNA gene may be at higher risk for ototoxicity, even if the patient’s aminoglycoside serum levels were within the recommended range.
In case of family history of aminoglycoside- induced deafness or known mitochondrial DNA mutations in the 12S rRNA gene, alternative treatments other than aminoglycosides may need to be considered. Patients who develop cochlear damage may not have symptoms during therapy to warn of eighth- nerve toxicity, and partial or total irreversible bilateral deafness may continue to develop after the drug has been discontinued.
Nephrotoxicity Rarely, nephrotoxicity may not become manifest until the first few days after cessation of therapy. Aminoglycoside-induced nephrotoxicity is usually reversible. Therefore, renal and eighth cranial nerve function should be closely monitored in patients with known or suspected renal impairment and also in those whose renal function is initially normal but who develop signs of renal dysfunction during therapy.
Elderly In elderly patients, it is particularly important to monitor renal function, when reduced renal function may not be evident in the results of routine screening tests, such as blood urea or serum creatinine. A creatinine clearance determination may be more useful.
Intrathecal administration. 1. Because of the known cross-allergenicity of drugs in this class, hypersensitivity to any aminoglycoside is a contraindication to the use of tobramycin.
Not medical advice. Always read the patient information leaflet and follow your prescriber or pharmacist.
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Following intravenous infusion of the same dose over 30-60 minutes, similar plasma concentrations of the drug are obtained. Elderly As for adults, but see recommendations for patients with impaired renal function. 5 mg/kg/day, administered in 3 or 4 equally divided doses.
It may be necessary to administer higher doses in some patients. 5 kg body weight. In neonates, average peak plasma tobramycin concentrations of about 5 micrograms/ml are attained 30-60 minutes after a single IM dose of 2 mg/kg; plasma concentrations average 1-2 micrograms/ml at 12 hours.
Obese patients The appropriate dose may be calculated using the patient's estimated lean body weight, plus 40% of the excess, as the weight on which to determine mg/kg. Patients with impaired renal function Following a loading dose of 1 mg/kg, subsequent dosage must be adjusted, either with lower doses administered at 8 hr intervals or with normal doses at prolonged intervals, (see Table 2).
Both these regimens are suggested as guides to be used when serum levels of tobramycin cannot be measured directly. They are based on either the creatinine clearance or the serum creatinine of the patient, because these values correlate with the half-life of tobramycin.
Neither regimen should be used when dialysis is being performed. REGIMEN I - Reduced dosage at 8-hour intervals An appropriate reduced dosage range can be found in the accompanying table, (see Table 2) for any patient for whom the creatinine clearance or serum creatinine values are known.
The choice of dose within the indicated range should be based on the severity of the infection, the sensitivity of the pathogen, and individual patient considerations, especially renal function. Another rough guide for determining reduced dosage at 8-hour intervals, for patients whose steady-state serum creatinine values are known, is to divide the normally recommended dose by the patient's serum creatinine value (mg/100 ml).
REGIMEN II - Normal dosage at prolonged intervals Table 2 illustrates the recommended intervals between doses. As a general rule, the dosage frequency in hours can be determined by multiplying the patient's serum creatinine level (expressed as mg/100 ml) by six.
The dosage schedules derived from either method should be used in conjunction with careful clinical and laboratory observations of the patient and should be modified as necessary. 4). 9 >70 60mg 80mg q. 8 - 168 69 – 40 30 - 60mg 50 - 80mg q.
7 39 – 20 20 - 25mg 30 - 45mg q. 5 19 – 10 10 - 18mg 15 - 24mg q. 4 - 663 9 – 5 5 - 9mg 7 - 12mg q. 48h† * For life-threatening infections, dosages 50% […]
Reporting of suspected adverse reactions Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
Serum concentrations should be monitored when possible, and prolonged concentrations above 12 mg/litre should be avoided. A useful guideline would be to perform serum level assays after 2 or 3 doses and also at 3 or 4 day intervals during therapy, so that the dosage could be adjusted if necessary.
Rising trough levels (above 2 mg/L) may indicate tissue accumulation. Such accumulation and cumulative dose may contribute to ototoxicity and nephrotoxicity. 2). In order to measure the peak level, a serum sample should be drawn about 30 minutes following intravenous infusion or at one hour after intramuscular injection.
Trough levels are measured by obtaining serum samples at 8 hours or just prior to the next dose of tobramycin. Renal impairment In patients with normal renal function who do not receive tobramycin in higher doses or for longer periods of time than those recommended, the risk of toxic reactions is low.
However, patients with reduced renal function are prone to the potential ototoxic and nephrotoxic effects of this drug, so dosage should be adjusted carefully on the basis of regular monitoring of serum drug concentrations and of renal function.
Neurotoxic and / or nephrotoxic drugs Concurrent and sequential use of other nephrotic, neurotoxic or ototoxic drugs, particularly streptomycin, neomycin, kanamycin, gentamicin, cephaloridine, paromomycin, viomycin, polymyxin B, colistin, cisplatin, vancomycin and amikacin, should be avoided.
Advanced age and dehydration may also increase patient risk. Diuretics Tobramycin should not be given concurrently with potent diuretics. Some diuretics themselves cause ototoxicity, and diuretics administered intravenously enhance aminoglycoside toxicity by altering antibiotic concentrations in serum and tissue.
General It is desirable to measure both peak and trough serum concentrations as high doses of drug may be associated with a greater risk of toxicity. Cross-allergenicity among aminoglycosides has been known to occur. Patients treated with aminoglycoside antibiotics such as tobramycin should be under close clinical observation because these drugs have an inherent potential for causing nephrotoxicity and ototoxicity.
Serum calcium, magnesium and sodium should be monitored. It is particularly important to monitor serum levels closely in patients with known renal impairment. Urine should be examined for increased excretion of protein, cells and casts.
Serum creatinine or creatinine clearance (preferred over blood urea) should be measured periodically. When possible, it is recommended that serial audiograms be obtained in patients old enough to be tested, particularly high-risk patients.
In patients with extensive burns or cystic fibrosis, altered pharmacokinetics may result in reduced serum drug levels. Dosage must be based on measured serum levels in these patients. Administration Aminoglycosides may be absorbed in significant quantities from body surfaces for local irrigation or application and may cause neurotoxicity and nephrotoxicity.
Although not indicated for intraocular and/or subconjunctival use, there have been reports of macular necrosis following this type of injection. Effect on neuromuscular function Aminoglycosides should be used with caution in patients with muscular disorders, such as myasthenia gravis or parkinsonism, since these drugs may aggravate muscle weakness because of their potential curare-like effect on neuromuscular function.
Neuromuscular blockade or respiratory paralysis may occur following rapid intravenous administration of many aminoglycosides and have been reported in cats receiving very high doses of tobramycin (40mg/kg). The possibility of prolonged secondary apnoea should be considered if tobramycin is administered to anaesthetised patients who are also receiving neuromuscular blocking […]