Pholcodine should be used with caution in patients who have decreased respiratory reserve.
Pholcodine depresses the respiratory centre to some extent and should be used with caution in asthmatics. Since pholcodine is metabolised in the liver, its action may be prolonged in hepatic insufficiency. The dosage and frequency may need to be reduced in patients with impaired liver function.
Duro-Tuss/Duro-Tuss Forte contains sodium benzoate as a preservative.
Products containing sorbitol may have a laxative effect or cause diarrhoea.
Risks from Concomitant Use with Benzodiazepines: Profound sedation, respiratory depression, coma, and death may result from the concomitant use of Duro-Tuss/Duro-Tuss Forte with benzodiazepines. Observational studies have demonstrated that concomitant use of opioids and benzodiazepines increases the risk of drug-related mortality compared to use of opioids alone. Because of these risks, reserve concomitant prescribing of these drugs for use in patients for whom alternative treatment options are inadequate.
If the decision is made to newly prescribe a benzodiazepine and an opioid together, prescribe the lowest effective dosages and minimum durations of concomitant use.
If the decision is made to prescribe a benzodiazepine in a patient already receiving an opioid, prescribe a lower initial dose of the benzodiazepine than indicated in the absence of an opioid, and titrate based on clinical response.
If the decision is made to prescribe an opioid in a patient already taking a benzodiazepine, prescribe a lower initial dose of the opioid, and titrate based on clinical response.
Follow patients closely for signs and symptoms of respiratory depression and sedation. Advise both patients and caregivers about the risks of respiratory depression and sedation when Duro-Tuss/Duro-Tuss Forte is used with benzodiazepines. Advise patients not to drive or operate heavy machinery until the effects of concomitant use of the benzodiazepine have been determined. Screen patients for risk of substance use disorders, including opioid abuse and misuse, and warn them of the risk for overdose and death associated with the use of benzodiazepines (See Interactions).
Serotonin Syndrome with Concomitant Use of Serotonergic Drugs: Cases of serotonin syndrome, a potentially life-threatening condition, have been reported during concurrent use of Duro-Tuss/Duro-Tuss Forte with serotonergic drugs (See Interactions). This may occur within the recommended dosage range.
Serotonin syndrome symptoms may include mental-status changes (e.g. agitation, hallucinations, coma), autonomic instability (e.g. tachycardia, labile blood pressure, hyperthermia), neuromuscular aberrations (e.g. hyperreflexia, incoordination) and/or gastrointestinal symptoms (e.g. nausea, vomiting, diarrhoea) and can be fatal (See Interactions). The onset of symptoms generally occurs within several hours to a few days of concomitant use, but may occur later than that.
Discontinue Duro-Tuss/Duro-Tuss Forte if serotonin syndrome is suspected.
Adrenal Insufficiency: Cases of adrenal insufficiency have been reported with opioid use, more often following greater than one month of use.
Presentation of adrenal insufficiency may include non-specific symptoms and signs including nausea, vomiting, decreased appetite, fatigue, weakness, dizziness, and low blood pressure. If adrenal insufficiency is suspected, confirm the diagnosis with diagnostic testing as soon as possible. If adrenal insufficiency is diagnosed, treat with physiologic replacement dosing of corticosteroids. Wean the patient off of the opioid to allow adrenal function to recover and continue corticosteroid treatment until adrenal function recovers. Other opioids may be tried as some cases reported use of a different opioid without recurrence of adrenal insufficiency. The information available does not identify any particular opioids as being more likely to be associated with adrenal insufficiency.
Sexual Function/Reproduction: Long term use of opioids may be associated with decreased sex hormone levels and symptoms, such as low libido, erectile dysfunction, or infertility (See Postmarketing Experience under Adverse Reactions).