Conditions and symptoms
What Is Somnolence? Drowsiness on Medicine Labels
Somnolence · say it: SOM-nuh-lunssAlso written: drowsiness, sleepiness, sedation
Short answer
Somnolence means drowsiness or strong sleepiness. It is a common side effect listed on many medicine labels.
What it means
Somnolence is the medical word for drowsiness, a strong feeling of sleepiness or wanting to sleep at times when you would normally be awake. It can make you slower to react and less alert.
Many medicines list somnolence as a side effect, including some antihistamines, pain medicines, anti-seizure medicines, antidepressants and medicines for anxiety or sleep. The warning is mainly about safety: drowsiness can make driving, using machines or climbing ladders risky. It is often stronger when starting a medicine, after a dose increase, or when combined with alcohol or other sedating medicines.
Somnolence is different from fatigue (tiredness or low energy) and from insomnia (trouble sleeping). Being very hard to wake is not ordinary somnolence and needs urgent help.
Where you may see it
- Side effect lists in medicine leaflets
- Labels with 'May cause drowsiness. Alcohol may increase this effect.'
- Clinical trial tables in prescribing information
📄 How it looks on a report
Most common adverse reactions: somnolence, dizziness, headache.
🙅 What it does not mean
- It does not mean you will feel drowsy; many people do not.
- It often eases after the first days or weeks, but tell your doctor if it does not.
- Being very hard to wake is not normal drowsiness and needs urgent help.
🎯 Check yourself
Which of these is the right meaning of “Somnolence”?
🗒️ Questions to ask your doctor
💊 Medicines whose labels mention “Somnolence”
Plain-English explanations of each medicine, from its official FDA label.
- Acyclovir
An antiviral medicine of the nucleoside analogue type, used against herpesviruses
- Albuterol
A bronchodilator (a medicine that opens the airways) of the beta-2 adrenergic type. The FDA class is not listed, so this description comes from the label's own wording.
- Allopurinol
a xanthine oxidase inhibitor, a prescription medicine that acts on uric acid
- Alprazolam
a benzodiazepine, a type of central nervous system medicine
- Amitriptyline
An antidepressant of the tricyclic type
- Amlodipine
a calcium channel blocker, a type of medicine that relaxes blood vessels
- Amoxicillin and Clavulanate Potassium
A penicillin-class antibacterial combined with a beta-lactamase inhibitor, as the label describes it
- Aripiprazole
an atypical antipsychotic medicine
- Atenolol
a beta-blocker (beta-adrenergic blocker). The label describes it as a beta 1-selective, or cardioselective, blocking agent.
- Azithromycin
a macrolide antibacterial (antibiotic) medicine
🔗 Read more from trusted sources
- “Somnolence” on MedlinePlus ↗
US National Library of Medicine
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General information about a medical word, not advice about your own results. Ask the clinician who ordered the test what it means for you.