Augmentin for sore throat: when it is prescribed and the course of treatment

Acute tonsillopharyngitis is an inflammation of the tonsils and pharynx. It is most often caused by viruses, which are ineffective against antibiotics and increase the risk of side effects. Bacterial causes are most often associated with group A beta-hemolytic streptococcus. The key is to distinguish viral infection from streptococcal infection and prescribe antibiotics only if a bacterial infection is confirmed or highly suspected. [1]

Diagnosis includes clinical probability scores, such as the modified Centor index or FeverPAIN, and laboratory confirmation with a rapid streptococcal antigen test or throat culture. A positive test indicates the need for antibacterial therapy, while a negative test indicates symptomatic treatment. [2]

Even in cases of confirmed streptococcal infection, phenoxymethylpenicillin or amoxicillin remain the drugs of choice because they are highly targeted, effective, and safe. Broadening the spectrum unnecessarily increases the risk of adverse reactions and does not reduce the rate of treatment failure. [3]

Antibiotics shorten the duration of a sore throat by approximately 1 day and reduce the risk of early purulent complications and rare immune complications, such as acute rheumatic fever. This does not apply to viral forms, where antibiotics are of no benefit. [4]

Table 1. When is it justified to prescribe an antibiotic for acute tonsillopharyngitis?

Situation	What to do
Positive rapid strep test or positive culture	Prescribe an antibiotic
High clinical probability according to Centor or FeverPAIN and inability to test	Consider antibiotic or deferred prescription based on clinical judgment
Low clinical probability, negative test	Symptomatic therapy only
Suspected complication, such as peritonsillar abscess	Urgent assessment and antibiotic therapy according to protocols

Source: Clinical practice guidelines for sore throat and streptococcal pharyngitis. [5]

Place of amoxicillin plus clavulanic acid

Amoxicillin plus clavulanic acid is a combination of aminopenicillin and a beta-lactamase inhibitor. It is active against beta-lactamase-producing strains and extends the spectrum of coverage beyond that needed for typical uncomplicated streptococcal sore throat. Therefore, for isolated streptococcal tonsillopharyngitis, phenoxymethylpenicillin or amoxicillin remain the first-line therapy. [6]

The combination is appropriate in clinical situations where mixed flora with beta-lactamases is likely to be involved, such as recurrent tonsillitis, concomitant acute bacterial sinusitis, otitis media, stomatogenic processes, or failure of a preliminary course of amoxicillin despite adherence to the regimen. The choice should always be consistent with local epidemiology and the principles of antimicrobial vigilance. [7]

Broader-spectrum therapy has not been shown to reduce treatment failure rates compared with narrow-spectrum therapy in uncomplicated streptococcal pharyngitis, but does increase the risk of diarrhea and candidiasis. Therefore, broadening coverage should be justified by specific indications. [8]

If it is decided to use amoxicillin plus clavulanic acid, the dosage, duration and renal and hepatic function should be strictly adhered to in order to minimize the risk of adverse reactions. [9]

Table 2. First-line drugs and the place of amoxicillin plus clavulanic acid

Clinical scenario	Drug of choice	Alternative for intolerance	Comment
Confirmed uncomplicated streptococcal pharyngitis	Phenoxymethylpenicillin or amoxicillin	Cephalexin or cefadroxil for intolerance without anaphylaxis; clindamycin or a macrolide for true allergy	Narrow spectrum is preferred
Recurrent tonsillitis or concomitant acute bacterial sinusitis or otitis media	Amoxicillin plus clavulanic acid	According to indications, alternatives according to local protocols	Expansion of the spectrum is justified
Failure of amoxicillin treatment with confirmed compliance	Amoxicillin plus clavulanic acid	According to the readings	Rule out other causes

Sources: CDC, IDSA, national and regional antibiotic prescribing guidelines.[10]

Dosage regimens for adults

For adults and adolescents weighing 40 kg or more, one of two equivalent regimens is usually used: 875 mg plus 125 mg every 12 hours or 500 mg plus 125 mg every 8 hours. The choice of regimen is based on the severity of the infection, tolerability, and concomitant factors. [11]

Beta-lactam therapy for streptococcal pharyngitis typically lasts 10 days, which reduces the risk of relapse and complications. The course should be completed even if symptoms improve early. [12]

In severe cases, frequent relapses, or involvement of the paranasal sinuses, a more frequent dosing regimen may be warranted. The decision is made by the physician, taking into account local protocols and tolerability. [13]

In cases of impaired renal function, doses are adjusted, and the 875 mg plus 125 mg dose is avoided if the glomerular filtration rate is below 30 ml per minute. Monitoring of renal function and adverse reactions is especially important in the elderly. [14]

Table 3. Adult doses when choosing amoxicillin plus clavulanic acid

Scheme	Dose	Multiplicity	Typical duration
Standard	875 mg plus 125 mg	Every 12 hours	10 days
Alternative	500 mg plus 125 mg	Every 8 hours	10 days
Renal failure, glomerular filtration rate 10-30 ml per minute	500 mg or 250 mg	Every 12 hours	By severity
Renal failure, glomerular filtration rate below 10 ml per minute	500 mg or 250 mg	Every 24 hours	By severity

Source: official instructions and section on dose adjustments in patients with renal insufficiency. [15]

Dosages for children

For children 3 months and older, the dosage is calculated based on body weight. The standard range is 25-45 mg/kg per day of amoxicillin, divided into 2 doses every 12 hours, or 20-40 mg/kg per day, divided into 3 doses every 8 hours. The maximum daily dose should not exceed the adult dose. [16]

For recurrent tonsillitis, "low" dose ranges are acceptable, while for combined upper respiratory tract infections, such as otitis media or acute bacterial sinusitis, "high" dose ranges are often used, focusing on pneumococcal coverage. The physician makes the choice based on local susceptibility data. [17]

For children weighing 40 kg or more, adult dosages are used. For fixed-ratio formulations, the appropriate dosage form should be selected, and it should be noted that different tablets and chewable forms are not interchangeable. [18]

The course of treatment for streptococcal pharyngitis in children is also 10 days, unless otherwise specified by local protocol. Completing the course reduces the risk of relapse and complications. [19]

Table 4. Approximate doses for children by body weight

Body weight	Daily dose of amoxicillin every 12 hours	An example of division into reception
10 kg	250-450 mg per day	125-225 mg twice
20 kg	500-900 mg per day	250-450 mg twice
30 kg	750-1350 mg per day	375-675 mg twice
40 kg and more	See adult dosages	According to adult schemes

Sources: official instructions and national data on pediatric dosing. [20]

Contraindications, warnings and dose adjustments

Contraindicated in severe hypersensitivity reactions to penicillins and other beta-lactam antibiotics, as well as in patients with a history of cholestatic jaundice or liver dysfunction associated with the use of a combination of amoxicillin and clavulanic acid. If signs of an immediate allergic reaction occur, discontinue the drug and provide emergency care. [21]

Dose adjustment is necessary in severe renal failure. Patients with a glomerular filtration rate below 30 ml/min should not be prescribed the 875 mg plus 125 mg dose. In patients with liver dysfunction, use with caution and monitor parameters. [22]

Rare but serious skin reactions, such as Stevens-Johnson syndrome, toxic epidermal necrolysis, drug reaction with eosinophilia and systemic manifestations, and acute generalized exanthematous pustulosis, should be considered. If a rash with systemic manifestations occurs, the drug should be discontinued. [23]

There is a risk of drug-induced liver injury, more common in older men and with prolonged use. The damage is usually reversible, but severe cases with prolonged jaundice have been reported. It is important to evaluate the benefit-risk ratio, especially in the absence of clear indications for an extended-spectrum regimen. [24]

Table 5. Who is contraindicated for the drug and when is dosage adjustment necessary?

Situation	Action
True allergy to penicillins or severe reaction to other beta-lactams	Do not prescribe
Pre-existing cholestatic jaundice secondary to amoxicillin/clavulanic acid combination therapy	Do not prescribe
Glomerular filtration rate below 30 ml per minute	Avoid dose of 875 mg plus 125 mg, adjust dosage
Liver dysfunction	Use with caution, monitor

Source: Official instructions and database on drug-induced liver injury. [25]

Drug interactions

The combination may prolong prothrombin time when used concomitantly with oral anticoagulants. Monitoring of the international normalized ratio and, if necessary, adjustment of the anticoagulant dose is required. [26]

Concomitant use with allopurinol increases the risk of skin rash. Combination with probenecid is not recommended due to increased amoxicillin concentrations. [27]

The comprehensive data on the impact on the efficacy of oral hormonal contraceptives are mixed. A randomized trial showed no significant effect on the international normalized ratio in patients on warfarin in the absence of infection, and there is insufficient evidence of a decrease in contraceptive efficacy with most antibiotics, including this combination. In practice, additional contraception is recommended for severe diarrhea or vomiting. [28]

When performing laboratory tests, false-positive results for certain immunological tests are possible. This point is taken into account when interpreting the tests. [29]

Table 6. Key interactions and tactics

Drug or situation	Possible effect	What to do
Oral anticoagulants	Prolongation of prothrombin time	Monitoring and dose adjustment of anticoagulant
Allopurinol	Increased risk of rash	Avoid combination or observe carefully
Probenecid	Increased concentration of amoxicillin	Do not combine
Oral contraceptives	Theoretically, decreased effectiveness in intestinal disorders	Additional contraception for vomiting or diarrhea

Source: Official drug label and interaction reviews.[30]

Side effects and safety

The most common adverse reactions are diarrhea, nausea, abdominal pain, rash, and candidiasis. In rare cases, severe diarrhea associated with clostridioids develops, requiring immediate discontinuation of the drug and specific treatment. [31]

There are descriptions of drug-induced liver injury with cholestatic jaundice. The changes are usually reversible, but recovery can be prolonged. The risk is higher in the elderly and with long-term use. [32]

Serious skin reactions, such as Stevens-Johnson syndrome and toxic epidermal necrolysis, are extremely rare but potentially dangerous. The development of progressive rash, fever, and mucosal lesions is a reason to immediately discontinue the drug and seek medical attention. [33]

In patients with infectious mononucleosis, the use of aminopenicillins often causes a generalized rash, so the drug is not recommended in such cases. [34]

Table 7. Adverse reactions and patient actions

Reaction	Typicality	What to do
Mild diarrhea	Often	Drinking regime, observation
Severe diarrhea with blood or fever	Rarely	Consult a doctor immediately and stop taking the drug.
Itchy rash, swollen lips, difficulty breathing	Rarely	Stop taking the medicine immediately and call emergency services.
Darkening of urine, yellowing of the skin	Rarely	Stop taking it and get your liver tested.

Source: Official label and safety profile.[35]

Efficiency, duration, prevention of complications

In confirmed streptococcal infections, beta-lactams reduce symptoms and decrease the risk of complications, including rheumatic fever. However, a narrow spectrum is preferable, as broad-spectrum therapies do not reduce the risk of failure but are more likely to cause side effects. [36]

The recommended duration of treatment with oral beta-lactams is 10 days for both children and adults. Treatment should not be discontinued without consultation, even if symptoms resolve earlier. [37]

In case of frequent relapses and treatment failures, it is important to evaluate compliance with the regimen, exclude carriage, consider concomitant foci of infection in the paranasal sinuses and oral cavity, and reconsider tactics taking into account local sensitivity. [38]

Prevention of complications includes timely initiation of treatment upon confirmation of the diagnosis and a full course of treatment, which reduces the risk of peritonsillar abscess and inflammatory post-streptococcal complications. [39]

Table 8.

Step	Action
1	Assess the clinical probability of a viral infection using a scale and symptoms
2	Perform a rapid strep test and culture if necessary.
3	If confirmed, prescribe a narrow beta-lactam for 10 days; if intolerance is present, consider alternatives.
4	Consider amoxicillin plus clavulanic acid only when clearly indicated.
5	Monitor symptoms and tolerance, complete the course

Sources: CDC, NICE, IDSA. [40]

Frequently asked questions

Is it safe to start a combination regimen "just in case" for a sore throat without testing?
No. Most cases are viral. Antibiotics do not speed recovery from a viral cause and increase the risk of adverse reactions. The diagnosis should be confirmed by testing or culture. [41]

How many days should I take it?
For beta-lactams for streptococcal pharyngitis, the recommended course is 10 days for both children and adults. Not completing the full course increases the risk of relapse and spread of infection. [42]

What can be used instead for penicillin allergies?
In the absence of anaphylaxis, cephalexin or cefadroxil can be considered. For true allergies, clindamycin or a macrolide is recommended, given the increasing resistance to macrolides. [43]

Should a macrolide be used "just to be on the safe side"?
No. Combining classes without indications increases risks and does not improve outcomes in standard tonsillitis. Drug selection should be targeted and well-founded. [44]