© 2003-17 Susan K. Mikota DVM and Donald C. Plumb, Pharm.D. Published by
Elephant Care International
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For general information on the cephalosporins including adverse effects, contraindications, overdosage, drug interactions, and monitoring parameters, refer to the monograph: Cephalosporins, General Information.
Chemistry – An injectable semi-synthetic cephalosporin antibiotic, cephalothin sodium occurs as a practically odorless, white to off-white, crystalline powder. It is freely soluble in water and very slightly soluble in alcohol. Each gram of the injection contains 2.8 mEq of sodium. After reconstitution the solution for injection has a pH of 6.0-8.5.
Storage/Stability/Compatibility – The sterile powder for injection and reconstitution should be stored at room temperature. After reconstituting with sterile water for injection, cephalothin sodium neutral is stable for 12 hours at room temperature and 96 hours when refrigerated. Precipitates may occur with refrigerated solutions, but can be redissolved with warming and agitation. Solutions may darken, particularly at room temperature, but this does not indicate any loss of potency. In the frozen state, cephalothin sodium solutions are relatively stable.
The following drugs or solutions are reportedly compatible with cephalothin: D25W/Amino Acids 4.25%, D5W in Lactated Ringer’s, D5W in sodium chloride 0.2% – 0.9%, D5W, D10W, Lactated Ringer’s Injection, normal saline, ascorbic acid injection, chloramphenicol sodium succinate, clindamycin phosphate, cytarabine, fluorouracil, heparin sodium, hydrocortisone sodium succinate, magnesium sulfate, metaraminol bitartrate, methotrexate, nitrofurantoin sodium, oxacillin sodium, phytonadione, polymyxin B sulfate, potassium chloride, sodium bicarbonate and vitamin B-complex with C.
The following drugs or solutions are reportedly incompatible or only compatible in specific situations with cephalothin: amikacin sulfate, aminophylline, bleomycin sulfate, calcium chloride/gluconate, cimetidine HCl, dopamine HCl, doxorubicin HCl, erythromycin lactobionate, gentamicin sulfate, isoproterenol HCl, kanamycin sulfate, norepinephrine bitartrate, oxytetracycline HCl, penicillin G potassium/sodium, phenobarbital sodium, prochlorperazine edisylate and tetracycline HCl.
Compatibility is dependent upon factors such as pH, concentration, temperature and diluents used. It is suggested to consult specialized references for more specific information (e.g., Handbook on Injectable Drugs by Trissel; see bibliography).
Pharmacology/Spectrum of Activity – A first generation cephalosporin, cephalothin exhibits activity against the bacteria usually covered by this class. Refer to the monograph: Cephalosporins, General Information for more specific information.
Uses/Indications – In the United States, there are no cephalothin products approved for veterinary species, but it has been used clinically in several species when a relatively short-acting, injectable, first generation cephalosporin is indicated.
Pharmacokinetics (specific) – Cephalothin is not appreciably absorbed after oral administration and must be given parenterally to achieve therapeutic serum levels. Absorbed drug is partially metabolized by the liver and kidneys to desacetylcephalothin which is about 25% as active an antibacterial as the parent compound. In humans, about 60-95% of the drug is excreted unchanged into the urine and 27-54% of a dose is excreted as the desacetyl metabolite. Elimination half-lives may be significantly prolonged in patients with severely diminished renal function. Pharmacokinetic parameters for dogs and horses follow:
In dogs, the apparent volume of distribution at steady state is 435 ml/kg, total body clearance of 11.6 – 15 ml/min/kg with a serum elimination half-life of 42-51 minutes.
In horses, the apparent volume of distribution at steady state is 145 ml/kg, total body clearance of 13 ml/min/kg with a serum elimination half-life of 15 minutes when given IV and 49 minutes after IM injection. Cephalothin is about 20% bound to equine plasma proteins.
Doses – Note: IM injection may be very painful.
For susceptible infections:
a) 11 – 18 mg/kg IM or IV qid (Robinson 1987)
b) Foals: 20 – 30 mg/kg IV q6h (Caprile and Short 1987)]
c) 18 mg/kg IM or IV q6h (Beech 1987b)
Dosage Forms/Preparations/FDA Approval Status –
Veterinary-Approved Products: None
Cephalothin Sodium Powder for Injection 1 g, 2 g in 10 ml vials and 100 ml piggyback vials and Faspak; Keflin®, Neutral (Lilly), generic (Rx)
Cephalothin Sodium Injection 1 g and 2 g in 5% dextrose premixed bags in 50 ml D5W (frozen); Cephalothin Sodium® (Baxter); (Rx)