Case 4: A 3-year-old child has fever, signs of acute respiratory viral infections Objectively: the general condition is satisfactory, the pharynx is hyperemic. Body temperature is 38.8 C. In the lungs without pathology. Station 1 1. Identify the problem (diagnosis): 2. Choose your P-medication for this condition: 3. Dosage form 4. Dosage Station 2 5. Pharmacokinetics of the drug 6. Mechanism of action 7. Write a prescription Station 3 8. Duration of treatment 9. Side effects 10. Contraindications

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Case 4 — 3-Year-Old Child: Fever + Acute URTI

Station 1

1. Problem / Diagnosis

Acute respiratory viral infection (ARVI) with fever (38.8°C) in a 3-year-old child. The clinical picture — fever, hyperemic pharynx, lungs clear — is consistent with an uncomplicated upper respiratory tract infection of viral etiology requiring symptomatic antipyretic therapy.

2. P-Drug (Preferred Medication)

Paracetamol (Acetaminophen)

Rationale: It is the first-line antipyretic/analgesic in children. Aspirin is contraindicated in children under 15 years (risk of Reye's syndrome). Ibuprofen is acceptable as an alternative but paracetamol is preferred as the safest first choice for uncomplicated fever in a 3-year-old.

3. Dosage Form

Oral suspension (syrup) — e.g., 120 mg/5 mL or 250 mg/5 mL pediatric suspension. A suppository (rectal) form is an alternative if oral administration is not tolerated.

4. Dosage

10–15 mg/kg per dose, every 4–6 hours as needed.

For a typical 3-year-old (~14–15 kg):

~150 mg per dose (i.e., ~6 mL of 120 mg/5 mL suspension)
Maximum: 75 mg/kg/day, not to exceed 3 g/day

Station 2

5. Pharmacokinetics

Administration: Oral (or rectal)
Absorption: Well absorbed from the GI tract; peak plasma concentration reached in 30–60 minutes after oral administration
Protein binding: Poorly bound to plasma proteins
Metabolism: Primarily hepatic — conjugated to inactive sulfate and glucuronide metabolites (>95%); a minor fraction is converted by CYP2E1 to the toxic reactive metabolite NAPQI (N-acetyl-p-benzoquinone imine), which is normally detoxified by glutathione
Excretion: Renal; <5% excreted unchanged
Half-life: 2–3 hours (normal therapeutic doses); prolonged in liver disease or overdose

— Katzung's Basic and Clinical Pharmacology, 16th Edition

6. Mechanism of Action

Paracetamol is a weak inhibitor of COX-1 and COX-2 in peripheral tissues, accounting for its analgesic and antipyretic effects. It acts centrally to reduce fever by inhibiting prostaglandin synthesis in the hypothalamus (thermoregulatory center), thereby lowering the elevated set-point. Additional antinociceptive mechanisms involve interactions with endogenous opioid, cannabinoid, and serotonergic systems. Notably, it has no significant anti-inflammatory effect and does not inhibit platelet aggregation.

— Katzung's Basic and Clinical Pharmacology, 16th Edition

7. Prescription

Rp:
  Paracetamol (Acetaminophen) suspensio 120 mg/5 mL
  Flakon 100 mL                           D.t.d. No. 1

  S: Give 6 mL (= 120–150 mg) orally every 4–6 hours
     as needed for fever or discomfort.
     Do not exceed 4 doses in 24 hours.
     Shake well before use.

Signa: For oral use in children only.
       #  [Physician signature / date]

Station 3

8. Duration of Treatment

Paracetamol in ARVI is used symptomatically, not for a fixed course:

Administer only when the child is febrile or uncomfortable (do not give around the clock)
Typical duration: 3–5 days, or until fever resolves
If fever persists beyond 3–5 days without improvement, reassess for bacterial superinfection

9. Side Effects

In therapeutic doses, paracetamol is very well tolerated. Possible adverse effects:

Severity	Effect
Mild (rare)	Transient elevation of hepatic enzymes
Overdose	Hepatotoxicity (centrilobular necrosis) — the most serious and common toxic effect
Overdose	Acute renal tubular necrosis
Early overdose signs	Nausea, vomiting, diarrhea, abdominal pain
Very rare	Hemolytic anemia, methemoglobinemia, anaphylaxis, severe skin reactions (Stevens-Johnson)

Antidote for overdose: N-acetylcysteine (acetylcysteine) — replenishes glutathione to neutralize NAPQI.

— Katzung's Basic and Clinical Pharmacology, 16th Edition

10. Contraindications

Severe hepatic impairment or active liver disease (paracetamol is primarily hepatically metabolized)
Known hypersensitivity to paracetamol
Chronic alcohol use / alcoholic liver disease (increased NAPQI production)
Caution in severe renal impairment (accumulation of metabolites)
Do not combine with other paracetamol-containing products (risk of inadvertent overdose)
Aspirin is absolutely contraindicated in children <15 years (Reye's syndrome)

Summary: This is a straightforward case of viral ARVI with fever in a toddler. The P-drug of choice is paracetamol oral suspension 10–15 mg/kg/dose q4–6h PRN, which is safe, effective, and widely recommended as first-line antipyretic therapy in pediatric patients.

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