Silphen Cough Side Effects
Generic name: diphenhydramine
Medically reviewed by Drugs.com. Last updated on Oct 3, 2022.
Note: This document contains side effect information about diphenhydramine. Some dosage forms listed on this page may not apply to the brand name Silphen Cough.
More frequent side effects include: sedated state and thickening of bronchial secretions. Continue reading for a comprehensive list of adverse effects.
Applies to diphenhydramine: oral capsules and tablets, parenteral injection.
Side effects include:
Sedation, sleepiness, dizziness, disturbed coordination, epigastric distress, thickening of bronchial secretions.
For Healthcare Professionals
Applies to diphenhydramine: compounding powder, injectable solution, oral capsule, oral disintegrating strip, oral liquid, oral tablet, oral tablet chewable, oral tablet disintegrating.
The most commonly reported side effects included somnolence, dizziness, and incoordination.[Ref]
Common (1% to 10%): Sedation/somnolence/sleepiness, drowsiness, unsteadiness, dizziness, headache, attention disturbance
Rare (0.01% to 0.1%): Extrapyramidal effects, tremor, convulsions
Frequency not reported: Paresthesia, dyskinesia/muscle dyskinesia, vertigo, neuritis, incoordination, psychomotor impairment, activation of epileptogenic foci[Ref]
Drowsiness usually diminishes after a few days.[Ref]
Common (1% to 10%): Dry mouth
Frequency not reported: Gastrointestinal disturbance, nausea, vomiting, constipation, diarrhea, dyspepsia, epigastric distress[Ref]
Common (1% to 10%): Fatigue
Frequency not reported: Lassitude, tinnitus, acute labyrinthitis, asthenia, chills, impaired performance (including impaired driving, work, and/or information processing)[Ref]
Rare (0.01% to 0.1%): Confusion, depression, sleep disturbances
Frequency not reported: Paradoxical excitation/excitation, agitation, increased energy, restlessness, nervousness, euphoria, anxiety, hallucinations, insomnia, irritability[Ref]
Rare (0.01% to 0.1%): Palpitations, hypotension, arrhythmia
Frequency not reported: Tachycardia, chest tightness, extrasystoles[Ref]
Rare (0.01% to 0.1%): Blood disorders
Frequency not reported: Hemolytic anemia, thrombocytopenia, agranulocytosis[Ref]
Rare (0.01% to 0.1%): Hypersensitivity reactions
Frequency not reported: Angioedema, anaphylactic shock[Ref]
Rare (0.01% to 0.1%): Liver dysfunction[Ref]
Frequency not reported: Rash, urticaria, skin rashes, erythema, photosensitivity, pruritus, drug rash, excessive perspiration[Ref]
Frequency not reported: Dyspnea, thickening of bronchial secretions, throat tightening, wheezing, nasal stuffiness, dry nose or throat[Ref]
Frequency not reported: Urinary hesitancy/difficulty/retention, dysuria, early menses[Ref]
Frequency not reported: Blurred vision, dry eyes, diplopia[Ref]
Frequency not reported: Increased appetite, anorexia[Ref]
Frequency not reported: Muscle twitching/weakness[Ref]
Frequently asked questions
- How much Benadryl can I take? What is too much?
- What is the max dose of diphenhydramine for adults?
- Does diphenhydramine raise blood pressure?
- Can diphenhydramine be used as a sleep aid?
- How long does Benadryl take to work?
- Does Benadryl make you sleepy?
- Diphenhydramine Hydrochloride vs Citrate: What's the difference?
- Can you take Benadryl while pregnant?
More about Silphen Cough (diphenhydramine)
- Check interactions
- Compare alternatives
- Latest FDA alerts (2)
- Dosage information
- During pregnancy
- Drug class: anticholinergic antiemetics
Benadryl, Banophen, ZzzQuil, Benadryl Allergy, ... +18 more
Related treatment guides
1. "Product Information. Benadryl (diphenhydramine)." Parke-Davis (2002):
2. "Product Information. Benadryl Children's Allergy Fastmelt (diphenhydrAMINE)." Pfizer U.S. Pharmaceuticals Group (2022):
3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
4. Cerner Multum, Inc. "Australian Product Information." O 0
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.