Sintrine 4 (montelukast 4 mg) is used primarily for asthma management in children and can cause a range of side effects, some of which may be serious or require medical attention[1].
Common (Frequent) Side Effects:
- Sleeplessness
- Abdominal (stomach) pain
- Thirst
- Headache
- Upper respiratory tract infections
- Diarrhoea, nausea, vomiting
- Rash
- Fever
- Elevated liver enzymes
Other common complaints can include skin rashes or lesions, dizziness, weakness/tiredness, and toothache[1][3][8].
Less Frequent Side Effects:
- Stuffy nose, coughing
- Heartburn, stomach flu
- Indigestion, dry mouth
- Joint or muscle pain, cramps
- Bedwetting in children (enuresis)
- Nosebleed
- Drowsiness, dizziness, pins and needles/numbness
- Bruising, itching, hives
- Weakness/tiredness, feeling unwell, swelling
- Behavior and mood changes (dream abnormalities, nightmares, trouble sleeping, sleepwalking, irritability, feeling anxious, restlessness)
Several behavioral and neuropsychiatric effects, such as agitation, depression, hallucinations, disorientation, suicidal thoughts and actions, and increased bleeding tendency, have also been reported[1][3][8].
Rare but Serious Side Effects:
- Hepatitis (inflammation of the liver), including cholestatic and hepatocellular injury
- Severe skin reactions (erythema multiforme, Stevens-Johnson syndrome)
- Seizure
- Rapid or irregular heartbeat (palpitations)
- Churg-Strauss syndrome (systemic vasculitis often presenting with flu-like illness, pins and needles/numbness, worsening lung symptoms, rash)
- Low blood platelet count
- Allergic reactions (swelling of face, lips, tongue or throat, breathing difficulties, hives)
Some of these effects may require urgent medical attention, especially swelling, trouble breathing, suicidal thoughts or actions, and severe skin reactions[3][5][7][8].