What are the recommended doses of Tussionex (hydrocodone‑polistirex/chlorpheniramine‑polistirex) oral solution for adults and children, and how should dosing be adjusted in patients with hepatic or renal impairment, the elderly, or those taking other central nervous system (CNS) depressants?

Tussionex Dosing

Tussionex (hydrocodone-polistirex/chlorpheniramine-polistirex) should not be used in patients under 18 years of age due to lack of efficacy data and significant risk of fatal respiratory depression, and in adults, standard dosing must be reduced by approximately 30-50% in hepatic impairment and 50-70% in moderate-to-severe renal impairment, with elderly patients requiring similar dose reductions. 1, 2

Pediatric Population (Under 18 Years)

• Tussionex is contraindicated in all patients under 18 years of age. The FDA determined that hydrocodone-containing cough medications should no longer be indicated for treatment of cough in this population due to unfavorable benefit-risk profile. 1
• No robust efficacy data exist for hydrocodone/chlorpheniramine in relieving cough and upper respiratory symptoms in patients aged 6 to <18 years, while fatal respiratory depression has been documented. 1
• Ten pediatric deaths were reported after taking hydrocodone-containing cough medicines, with nine due to overdose. 1

Adult Dosing (18 Years and Older)

Standard Adult Dose

• The typical adult dose is based on the hydrocodone component, with careful attention to the extended-release formulation properties. 1
• Dosing intervals must account for the polistirex (extended-release) formulation, which provides prolonged drug release compared to immediate-release products. 2

Dosing Adjustments in Special Populations

Hepatic Impairment

• In moderate hepatic impairment, reduce the dose by approximately 30-50% due to increased systemic exposure (up to 70% higher AUC). 2
• Hydrocodone undergoes significant first-pass metabolism; porto-systemic shunting in liver disease increases oral bioavailability of this highly extracted drug. 3
• Use lower starting doses and extend dosing intervals to avoid accumulation, as drug clearance is decreased in moderate-to-severe hepatic impairment. 3
• Avoid Tussionex in severe hepatic impairment due to risk of precipitating or aggravating hepatic encephalopathy and unpredictable drug accumulation. 3
• Monitor closely for signs of respiratory depression and CNS depression, as all opioids can precipitate hepatic encephalopathy in severe liver disease. 3

Renal Impairment

• In moderate renal impairment, reduce the dose by approximately 30-40%; in severe renal impairment or end-stage renal disease, reduce by 50% or more. 2
• Mean AUC increases by approximately 70% in moderate renal impairment and 75% in severe renal impairment compared to normal renal function. 2
• The half-life of hydrocodone and its active metabolites is increased in renal dysfunction, requiring longer intervals between doses. 4
• Monitor creatinine clearance regularly, as functional impairment of excretory organs is common in elderly patients. 4

Elderly Patients (65 Years and Older)

• Start with doses reduced by 50% in patients over 65 years due to increased sensitivity to opioid effects and higher risk of adverse events. 4
• Elderly patients often have concurrent renal impairment (even with normal serum creatinine due to decreased muscle mass), necessitating dose reduction. 4
• Use longer intervals between doses and slower dose titration to reduce the incidence of typical adverse events such as nausea, vomiting, and respiratory depression. 4
• Monitor specifically for CNS depression, falls risk, constipation, and urinary retention due to the anticholinergic effects of chlorpheniramine. 5

Concurrent CNS Depressants

• Reduce Tussionex dose by at least 50% when used with other CNS depressants including benzodiazepines, other opioids, or alcohol due to increased risk of respiratory depression and oversedation. 5, 4
• Exercise extreme caution when combining with benzodiazepines; fatalities have been reported with concurrent use of benzodiazepines and opioids. 5
• Avoid concurrent use with other anticholinergic medications in elderly patients due to additive anticholinergic effects (confusion, urinary retention, constipation). 5

Critical Monitoring Parameters

• Monitor for respiratory depression, especially in the first 24-72 hours after initiation or dose increase, as this is the most significant threat in opioid-treated patients. 4
• Assess for signs of oversedation, confusion, or altered mental status, particularly in elderly or renally/hepatically impaired patients. 2
• Monitor renal function (creatinine clearance) and hepatic function before initiating therapy and periodically during treatment. 4, 2

Common Pitfalls to Avoid

• Do not assume normal renal function in elderly patients based solely on serum creatinine; calculate creatinine clearance, as decreased muscle mass can mask renal impairment. 4
• Do not use standard adult doses in patients over 65 years without dose reduction, as age-related pharmacokinetic changes significantly increase drug exposure. 4
• Avoid prescribing Tussionex with MAOIs or within 14 days of MAOI discontinuation due to risk of serotonin syndrome (from the opioid component). 5
• Do not combine with other medications that prolong QTc interval without ECG monitoring, as chlorpheniramine may have cardiac effects. 5