Clavamox (Amoxicillin/Clavulanate)

(combination drug: amoxicillin trihydrate/clavulanate potassium, amoxicillin trihydrate/clavulanic acid)

Brands

Veterinary: Clavamox, Synulox

Veterinary Availability:

Oral suspension: Clavamox Drops in 15-mL bottles containing 50 mg of amoxicillin trihydrate/12.5 mg of clavulanic acid per mL.
Tablets: 62.5 mg, 125 mg, 250 mg, 375 mg, 500 mg, 625 mg, 1000 mg

Brands

Human: Augmentin, Amoxil

Human Availability:

Comes in several forms: tablets, oral suspension, chewable tablets

Pharmacology

Amoxicillin, an aminopencillin beta-lactam, differs structurally from ampicillin by having an addition hydroxyl group on the phenyl ring. It is a bactericidal, broad-spectrum, antibiotic.
When Clavulanate Acid or its potassium salt form, Clavulanate Potassium, (beta-lactamase inhibitors) are used in combined form with the penicillins, such as amoxicillin, they prevent hydrolyzed penicillins like amoxicillin from being inactivated by bacterial beta-lactamases.

The antibacterial activity of clavulanate acid and its salt form clavulanate potassium are weak when used alone, and is therefore only available in combination form.

Studies have shown that amoxicillin/clavulanate has a wide range of activity against β-lactamase-producing strains of both Gram-positive and Gram-negative aerobes, facultative anaerobes, and obligate anaerobes.

Amoxicillin and clavulanic acid are both readily distributed into most body tissues and fluids. Note, that low concentrations of the drugs are found in saliva, sputum and uninflamed meninges while high concentrations are found in inflamed meninges. Both amoxicillin and clavulanic acid readily cross the placenta. However, studies revealed no adverse effects on embryo or fetal development in rats, and only low levels passed in breast milk making the drug safe to give in pregnant and lactating rats. Most of the amoxicillin is excreted unchanged in the urine. Excreted levels of clavulanic acid is reported to be only 1/5th that of amoxicillin.

Indications

Used to treat:

Lower Respiratory Tract Infections – caused by S. pneumoniae and M. catarrhalis.
Otitis Media – caused by S. pneumoniae and M. catarrhalis.
Skin and Skin Structure Infections – caused by β-lactamase-producing strains of S. aureus, E. coli, and Klebsiella spp.
Urinary Tract Infections – caused by β-lactamase-producing strains of E. coli, Klebsiella spp. and Enterobacter spp.

Clinical Pearl

Although amoxicillin/clavulanate is commonly used against infections caused by S. pneumoniae, it should be noted that the organism Streptococcus does not produce beta-lactamase. If the organism Streptococcus is identified on culture an alternative choice would be to use azithromycin, or to combine the beta-lactamase inhibitor amoxicillin-clavulanate with azithromycin.

Drug Interactions or Contraindications

Concomitant use of Probenecid may decrease the ability of the kidneys to remove some antibiotics (e.g., amoxicillin/clavulanate) thereby increasing their plasma level.
May have synergistic effect against certain bacteria, when used with the aminoglycosides.

Adverse Reactions

Blood: anemias

GI: anorexia, diarrhea

Other: hypersensitivity reaction such as rash and itching. Prolonged high doses can cause neurotoxicity. When given orally the penicillin’s may alter gut flora, selecting out resistant bacteria residing in the colon (leading to superinfections).

Dosage Recommendations

Caution: Loose stool/diarrhea not an uncommon side effect of this antibiotic. Use higher doses judiciously where condition warrants. In the event loose stools/diarrhea cannot be controlled with probiotics contact veterinarian immediately to reduce antibiotic dose, stopping antibiotic, or switching to another antimicrobial to prevent complication of enterocolitis.

6.25 mg/lb, PO, BID ⁴^, ¹². Given over 10-14 days.

or

20 mg/kg, PO, q12hr ³⁴^, ³⁵^, ⁴¹^, ⁴³^, ⁴⁴

or

30 mg/kg to 40mg/kg, PO, q12hr ²¹. Dosage range used successfully in pet rats by Vanessa Pisano DVM.

or

100 mg/kg, PO, SQ, q12hr ²⁹^, ⁴². *Note: use higher dosing cautiously*

Considerations

May give with food, does not significantly reduce absorption of drug.
Give yogurt, Lactobacillus capsules/granules, or Bene-Bac to help maintain normal gut flora.
Can be used simultaneously with Gentocin or Amikacin, or Baytril (enrofloxacin), or azithromycin.
Store tablets at dry, room temperature and away from heat.
For oral suspension shake well, refrigerate, and discard any unused portion after 10 days.