Spectinomycin
Spectinomycin hydrochloride / Spectinomycin sulfate
Also known as: Adspec · Spectam Scour-Halt · Spectoguard Scour-Chek · LS 50 · LincoSpectin · M-141 · actinospectacin · spectinomycini · U-18409AE · Kempi · Kirin · Stanilo · Togamycin · Trobicine · Vabicin
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For susceptible infections | 5.5-11 mg/kg | IM | q12h | — | 🌎 NA |
| For susceptible infections | 5-10 mg/kg | IM | q12h | — | 🌎 NA |
| For acute infectious gastroenteritis | 5-12 mg/kg | IM | q12h | — | 🌎 NA |
- For susceptible infections: Alternatively 22 mg/kg PO q12h (for enteric infections; not absorbed)
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For acute infectious gastroenteritis | 5-12 mg/kg | IM | q12h | — | 🌎 NA |
Birds
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For airsacculitis associated with M. meleagridis or chronic respiratory disease associated with E. coli in turkey poults (1-3 days old) | 0.1 mL (10 mg) | SC | once | — | 🌎 NA |
| For control and to lessen mortality due to infections from M. synoviae, S. typhimurium, S. infantis, and E. coli in newly hatched chicks | 2.55 mg/0.2 mL | SC | once | — | 🌎 NA |
| For prevention and control of chronic respiratory disease associated with Mycoplasma gallisepticum in broilers | 2 grams/gallon | PO | continuous in drinking water | — | 🌎 NA |
| For infectious synovitis associated with Mycoplasma synoviae in broilers | 1 gram/gallon | PO | continuous in drinking water | — | 🌎 NA |
| For improved weight gain/feed efficiency in floor-raised broilers | 0.5 grams/gallon | PO | continuous in drinking water | — | 🌎 NA |
- For airsacculitis associated with M. meleagridis or chronic respiratory disease associated with E. coli in turkey poults (1-3 days old): Inject in the base of the neck.
- For control and to lessen mortality due to infections from M. synoviae, S. typhimurium, S. infantis, and E. coli in newly hatched chicks: Dilute injection with normal saline to a concentration of 2.55 mg/0.2 mL and inject SC.
- For prevention and control of chronic respiratory disease associated with Mycoplasma gallisepticum in broilers: Add sufficient amount to drinking water to attain final concentration.
- For infectious synovitis associated with Mycoplasma synoviae in broilers: Add sufficient amount to drinking water to attain final concentration.
- For improved weight gain/feed efficiency in floor-raised broilers: Add sufficient amount to drinking water to attain final concentration.
Horses
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For susceptible infections | 20 mg/kg | IM | three times daily | — | 🌎 NA |
| For pneumonia | 20 mg/kg | IM | q8h | — | 🌎 NA |
- For pneumonia: May cause local myositis. Insufficient data to comment on use.
Cattle
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For bronchopneumonia and fibrinous pneumonia | 33 mg/kg | SC | q8h | — | 🌎 NA |
| For susceptible infections | 22-39.6 mg/kg/day | IM | divided three times daily | — | 🌎 NA |
| For bovine respiratory disease | 10-15 mg/kg | SC | once daily (q24h) | for 3-5 consecutive days | 🌎 NA |
- For bronchopneumonia and fibrinous pneumonia: Suggested withdrawal time is 60 days.
- For bovine respiratory disease: Inject in the neck; not more than 50 mL per site.
Swine
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For susceptible enteric infections | 10 mg/kg | PO | q12h | — | 🌎 NA |
| For bacterial enteritis (white scours) in baby pigs associated with E. coli susceptible to spectinomycin | 50 mg/10 lbs of body weight | PO | twice daily | for 3-5 days | 🌎 NA |
| For susceptible enteric infections | 10 mg/kg | IM | q12h | — | 🌎 NA |
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Spectinomycin is an aminocyclitol antibiotic, structurally related to aminoglycosides but lacking the amino sugars and glycosidic bonds.
Clinical Pearls:
- Bacteriostatic vs. Bactericidal: Because of its structural differences from true aminoglycosides, spectinomycin is bacteriostatic rather than bactericidal.
- Safety Profile: It notably lacks the severe nephrotoxicity and ototoxicity commonly associated with traditional aminoglycosides (like gentamicin or amikacin).
- Spectrum of Activity: It has a relatively broad spectrum against many gram-positive and gram-negative bacteria (including E. coli, Klebsiella, Proteus, Enterobacter, Salmonella, Streptococci, Staphylococcus, and Mycoplasma).
- Limitations: It has minimal to no activity against anaerobes, most strains of Pseudomonas, Chlamydia, or Treponema.
- Primary Use: It is predominantly used in food-producing animals (swine, poultry, cattle) for respiratory and enteric infections, though it is occasionally used off-label in dogs, cats, and horses.
Mechanism of action
Spectinomycin works by binding to the 30S ribosomal subunit of susceptible bacteria.
Mechanism Pathway: Drug enters bacterial cell → Binds specifically to the 30S ribosomal subunit → Inhibits mRNA translation and translocation → Halts protein synthesis → Bacteriostatic effect (prevents bacterial replication and growth).
Note: Unlike true aminoglycosides, spectinomycin does not cause misreading of the messenger RNA, which explains why its action is bacteriostatic rather than bactericidal.
Safety & warnings
Contraindications
- Patients with known hypersensitivity to spectinomycin
Adverse effects
- Neuromuscular blockade (reversible with parenteral calcium)
- Swelling or soreness at injection sites (especially SC in cattle)
- Transient ataxia (reported in turkey poults at high injected doses)
- Mild increases in BUN, ALP, and SGPT (reported in humans)
- Decreases in hemoglobin, hematocrit, and creatinine clearance (reported in humans)
Precautions
Neuromuscular Blockade: Like other aminocyclitols/aminoglycosides, spectinomycin can cause neuromuscular blockade, though it is generally safer. If this occurs, parenteral calcium administration will generally reverse the blockade.
- Pregnancy: FDA Category B in humans (animal studies have not demonstrated fetal risk, but adequate human studies are lacking). Use with caution.
- Nursing: It is unknown if spectinomycin is excreted in milk; use caution when administering to nursing patients.
- Tissue Irritation: Subcutaneous administration in cattle may cause localized swelling at the injection site.
Drug interactions
Antagonism has been reported when used concurrently.
Antagonism has been reported when used concurrently.
Monitoring
- Clinical efficacy (resolution of infection symptoms)
- Injection site monitoring for swelling or myositis
Pharmacokinetics
Absorption
Oral absorption is poor (only about 7% of the dose is absorbed), but the drug remaining in the GI tract is active locally. When injected SC or IM, the drug is well absorbed with peak serum levels occurring in about 1 hour.
Distribution
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 proteins. Placental and milk transfer are unknown.
Metabolism
Excreted mostly unchanged.
Elimination
Absorbed drug is excreted via glomerular filtration into the urine mostly unchanged. In cattle, the terminal half-life is about 2 hours.
Overdose
Because the drug is negligibly absorbed after oral administration, significant systemic toxicity is highly unlikely via the oral route.
Injected overdoses may cause neurological or neuromuscular signs. For example, injected doses of 90 mg produced transient ataxia in turkey poults. If severe neuromuscular blockade occurs following massive parenteral overdose, parenteral calcium administration may be required to reverse the blockade.
Available products
Formulations
- Injection (100 mg/mL)
- Water Soluble Concentrate (0.5 g/g)
- Oral Solution (50 mg/mL)
- Water Soluble Powder (Combination with Lincomycin)
Veterinary
- Spectinomycin Sulfate Injection: 100 mg/mL (Adspec)
- Spectinomycin Injection: 100 mg/mL (Spectam Injectable)
- Spectinomycin Water Soluble Concentrate: 0.5 gram/gram (Spectam Water Soluble)
- Spectinomycin Oral Solution: 50 mg/mL (Spectam Scour-Halt, Spectoguard Scour-Chek)
- Spectinomycin/Lincomycin combinations (LS 50 Water Soluble Powder, Sepclinx-50, LincoSpectin Sterile Solution)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Unless otherwise instructed by the manufacturer, spectinomycin products should be stored at room temperature (15-30°C). Protect from freezing.
Client information
Important Note: Spectinomycin is an antibiotic primarily used to treat specific bacterial infections in farm animals (like cattle, swine, and poultry), and occasionally for gastrointestinal infections in companion animals.
- Administration: Follow your veterinarian's instructions exactly. If giving an oral liquid or mixing into drinking water, ensure the animal consumes the full intended dose.
- Side Effects: This medication is generally very safe. If given by injection under the skin, you may notice mild swelling or soreness at the injection site.
- Completion of Therapy: Always complete the entire prescribed course of the antibiotic, even if your animal appears fully recovered. Stopping early can lead to resistant bacterial infections.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.