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S-T Forte 2 Side Effects

Generic name: chlorpheniramine / hydrocodone

Medically reviewed by Last updated on Oct 24, 2023.

Note: This document contains side effect information about chlorpheniramine / hydrocodone. Some dosage forms listed on this page may not apply to the brand name S-T Forte 2.

Applies to chlorpheniramine / hydrocodone: oral solution. Other dosage forms:


Oral route (Solution)

Warning: Addiction, Abuse, and Misuse; Life-Threatening Respiratory Depression, Accidental Ingestion, Medication Errors; Cytochrome P450 3A4 Interaction; Concomitant Use with Benzodiazepines or Other CNS Depressants; Interaction with Alcohol; Neonatal Opioid Withdrawal SyndromeHydrocodone bitartrate/chlorpheniramine maleate exposes users to risks of addiction, abuse, and misuse, which can lead to overdose and death. Assess patient’s risk before prescribing and monitor closely for these behaviors and conditions.Serious, life-threatening, or fatal respiratory depression may occur. Monitor closely, especially upon initiation or when used in patients at higher risk.Accidental ingestion of hydrocodone bitartrate/chlorpheniramine maleate, especially by children, can result in a fatal overdose of hydrocodone.Ensure accuracy when prescribing, dispensing, and administering hydrocodone bitartrate/chlorpheniramine maleate. Dosing errors can result in accidental overdose and death.Concomitant use with CYP3A4 inhibitors (or discontinuation of CYP3A4 inducers) can result in a fatal overdose of hydrocodone. Avoid the use of hydrocodone bitartrate/chlorpheniramine maleate in patients taking CYP3A4 inhibitors or inducers. Concomitant use of opioids with benzodiazepines or other central nervous system (CNS) depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death. Avoid the use of hydrocodone bitartrate/chlorpheniramine maleate in patients taking benzodiazepines, other CNS depressants, or alcohol.Instruct patients not to consume alcohol or any products containing alcohol while taking hydrocodone bitartrate/chlorpheniramine maleate because co-ingestion can result in fatal plasma hydrocodone levels.Hydrocodone bitartrate/chlorpheniramine maleate is not recommended for use in pregnant women. Prolonged use of hydrocodone bitartrate/chlorpheniramine maleate during pregnancy can result in neonatal opioid withdrawal syndrome, which may be life-threatening if not recognized and treated. If hydrocodone bitartrate/chlorpheniramine maleate is used for a prolonged period in a pregnant woman, advise the patient of the risk of neonatal opioid withdrawal syndrome and ensure that appropriate treatment will be available.

Serious side effects of S-T Forte 2

Along with its needed effects, chlorpheniramine / hydrocodone may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking chlorpheniramine / hydrocodone:

Incidence not known

Get emergency help immediately if any of the following symptoms of overdose occur while taking chlorpheniramine / hydrocodone:

Symptoms of overdose

Other side effects of S-T Forte 2

Some side effects of chlorpheniramine / hydrocodone may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Incidence not known

For Healthcare Professionals

Applies to chlorpheniramine / hydrocodone: oral capsule extended release, oral liquid, oral suspension extended release.


The more commonly reported adverse effects have included, sedation, somnolence, mental clouding, dizziness, nausea and vomiting.[Ref]


Frequency not reported: Dose-related respiratory depression including fatal respiratory depression, dryness of the pharynx, dryness of respiratory passages, laryngismus, wheezing, breathing trouble[Ref]

Nervous system

Frequency not reported: Sedation, somnolence, drowsiness, lethargy, mental and physical impairment, dizziness, headache, facial dyskinesia, feeling faint, lightheadedness, tremor[Ref]


Frequency not reported: Mental clouding, confusion, anxiety, fear, dysphoria, psychic dependence, mood changes, euphoria, agitation, irritability


Frequency not reported: Nausea, vomiting, constipation, abdominal pain, acute pancreatitis, dry mouth, dyspepsia, epigastric distress, loss of appetite[Ref]


Frequency not reported: Chest tightness


Frequency not reported: Skin rash, pruritus, erythema, urticaria, excessive perspiration[Ref]


Frequency not reported: Ureteral spasm, spasm of vesicle sphincters, urinary retention, dysuria, urinary frequency, urinary hesitancy[Ref]


Frequency not reported: Blurred, double, or other visual disturbances


1. (2006) "Product Information. Tussionex PennKinetic (chlorpheniramine-hydrocodone)." UCB Pharma Inc

2. (2006) "Product Information. HyTan (chlorpheniramine-hydrocodone)." Prasco Laboratories

3. (2017) "Product Information. Vituz (chlorpheniramine-hydrocodone)." Hawthorn Pharmaceuticals

4. (2017) "Product Information. TussiCaps (chlorpheniramine-hydrocodone)." ECR Pharmaceuticals

Further information

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.