Spectinomycin Hydrochloride
Chemistry - An aminocyclitol antibiotic obtained from Streptomyces spectabilis, specti Nomycin is available as the dihydrochloride pentahydrate. It occurs as a white to pale buff, crystalline powder with pKas of 7 and 8.7. It is freely soluble in water and practically in Soluble in alcohol.
Storage/Stability/Compatibility - Unless otherwise instructed by the manufacturer, spectinomycin products should be stored at room temperature (15-30° C).
Pharmacology - Spectinomycin is primarily a bacteriostatic antibiotic that inhibits protein synthesis in susceptible bacteria by binding to the 30S ribosomal subunit.
Spectinomycin has activity against a wide variety of gram positive and gram negative bacteria, including E. Coli, Klebsiella, Proteus, Enterobacter, Salmonella, Streptococci, Staphylococcus and Mycoplasma. It has minimal activity against anaerobes, most strains of Pseudomonas, Chlamydia, or Treponema. In human medicine, spectinomycin is used principally for its activity against Neissiera gonorrhoeae.
Uses/Indications - Although occasionally used in dogs, cats, horses and cattle for suscep Tible infections, spectinomycin is only approved for use in chickens, turkeys and swine. Refer to the Dosage section below for more information on approved uses.
Pharmacokinetics - After oral administration only about 7% of the dose is absorbed, but the drug that remains in the GI tract is active. When injected SQ or IM, the drug is report Edly well absorbed with peak levels occurring in about 1 hour.
Tissue levels of absorbed drug are lower than those found in the serum. Spectinomycin does not appreciably enter the CSF or the eye and is not bound significantly to plasma PRO Teins. It is unknown whether spectinomycin crosses the placenta or enters milk.
Absorbed drug is excreted via glomerular filtration into the urine mostly unchanged. No specific pharmacokinetic parameters were located for veterinary species.
Contraindications/Precautions/Reproductive Safety - Spectinomycin is contraindicated in patients hypersensitive to it. The reproductive safety of the drug is not known.
Adverse Effects/Warnings - When used as labeled, adverse effects are unlikely with this drug. It is reported that parenteral use of this drug is much safer than with other aminocy Clitol antibiotics, but little is known regarding prolonged use of the drug. It is probably safe to say that spectinomycin is significantly less ototoxic and nephrotoxic than other commonly used aminocyclitol antibiotics, but can cause neuromuscular blockade. Parenteral calcium administration will generally reverse the blockade.
Adverse effects that have been reported in human patients receiving the drug in single or multidose studies include soreness at injection site, increases in BUN, alkaline phos Phatase and SGPT, and decreases in hemoglobin, hematocrit and creatinine clearance. Although increases in BUN and decreases in creatinine clearance and urine output have been noted, overt renal toxicity has not been demonstrated with this drug.
Overdosage/Acute Toxicity - No specific information was located on oral overdoses, but because the drug is negligibly absorbed after oral administration, significant toxicity is un Likely via this route. Injected doses of 90 mg produced transient ataxia in Turkey poults.
Drug Interactions - Antagonism has been reported when spectinomycin is used with chloramphenicol or tetracycline.
Doses -
Horses:
For susceptible infections:
A) 20 mg/kg IM tid (Robinson 1987)
B) For pneumonia: 20 mg/kg IM q8h; May cause local myositis. Insufficient data to comment on use. (Beech 1987b)
Monitoring Parameters -
1) Clinical efficacy
No.
|
Item
|
Standard
|
Test Result
|
1
|
Appearance
|
white or almost white powder
|
Conforms
|
2
|
Specific Optical Rotation
|
15°21°
|
17°
|
3
|
Identification
|
Conforms
|
Conforms
|
4
|
Clarity Of Solution
|
Conforms
|
Conforms
|
5
|
Color Of Solution
|
Conforms
|
Conforms
|
6
|
PH
|
3.85.6
|
4.8
|
7
|
Water
|
16%20.0%
|
17.40%
|
8
|
Related Substances
|
Conforms
|
Conforms
|
9
|
Sulphate Ash
|
≤1.0%
|
0.40%
|
10
|
Bacterial Endotoxins
|
≤0.09EU/MG
|
Conforms
|
11
|
Assay(On Hydrous Basis)
|
95%100.5%
|
96.00%
|
12
|
Potency(On Hydrous Basis)
|
750U/MG800U/MG
|
787U/MG
|
Audited Supplier 
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