Rx Care

Antitussive offers convenient twice-daily dosing

Many clinicians prescribe antitussives for use at night to help patients sleep better. Fortunately, healthcare professionals can soon offer patients the first extended-release codeine-containing antitussive with 12-hour dosing.

The Food & Drug Administration recently approved codeine polistirex/chlorpheniramine polistirex (Codeprex, Celltech Group) extended-release suspension (CIII) for the temporary relief of cough, as may occur with the common cold or inhaled irritants, and for the temporary relief of runny nose; sneezing; itching of the nose or throat; and itchy, watery eyes due to hay fever, other upper respiratory allergies, or allergic rhinitis. The product is expected to be available in retail pharmacies by the fourth quarter.

Codeine/chlorpheniramine provides relief throughout the night, without a need for the middle-of-the-night dosing that interrupts sleep, said Norman LaFrance, M.D., senior VP for Medical and Regulatory Affairs at Celltech Pharmaceuticals in Rochester, N.Y. This helps improve patients' overall well-being and facilitates recovery, he said.

In addition, patient compliance improves with twice-daily dosing compared with dosing three or four times per day, said Anne Dalconzo, Pharm.D., senior medical information specialist for Celltech.

LaFrance said that codeine/chlorpheniramine uses Celltech's proprietary Pennkinetic extended-release drug delivery system, which is based on a controlled ion-exchange technology. According to the manufacturer, codeine is locked into the matrix of a nonabsorbable ion-exchange polymer, then coated with a semi-permeable membrane. Direct displacement of the active drug by ions in the gastrointestinal tract controls the drug's release from the polymer.

The system's design provides for a slowed rate of absorption and delayed peak plasma concentration, said LaFrance. "Peaks" and "valleys" in concentration levels are eliminated, giving codeine/chlorpheniramine prolonged antitussive and sedative actions, he continued. He also pointed out that the product has a pleasant cherry-cream flavor.

Codeine/chlorpheniramine is contraindicated in those sensitive to either codeine or chlorpheniramine, said Heleen DeCory, Ph.D., senior medical information specialist in the Medical Information, Education & Communications department at Celltech, and the primary scientist for the drug. She also warned of the possibility of tolerance and/or dependence, particularly in those with a history of substance abuse.

The manufacturer advised that chlorpheniramine should be used with caution in persons with persistent or chronic cough such as occurs with smoking, asthma, or emphysema, or with cough accompanied by excessive phlegm. The company also cautioned that the product should be used with caution in those taking other anticholinergic drugs, monoamine oxidase inhibitors (MAOIs), or tricyclic antidepressants. Reduced dosage of codeine/chlorpheniramine is recommended when the combo drug is used with MAOIs, tricyclic antidepressants, or central nervous system depressants such as antipsychotics or antianxiety agents. Antitussive activity should be monitored in those taking cytochrome P450 enzyme inducers or inhibitors, the manufacturer said.

Celltech reported that the most common side effects associated with the use of codeine/chlorpheniramine in clinical trials include drowsiness, confusion, dizziness, nausea, constipation, dry mouth, headache, and allergic reactions.

The recommended dose for those aged 12 and older is two teaspoonfuls (10 mL) every 12 hours, not to exceed four teaspoonfuls in 24 hours. For children ages six to under 12, the recommended dose is one teaspoonful (5 mL) every 12 hours, not to exceed two teaspoonfuls every 24 hours.

The role of the pharmacist in the treatment of a cough and cold depends on the stage of the illness at which the patient seeks treatment, said Dalconzo. Early in the course of their illness, patients may be able to use an over-the-counter preparation, she said. In the case of a more persistent cough, pharmacists ought to recommend that patients consult their physician.

Charlotte LoBuono

TIPS TO REMEMBER: Codeprex

• Codeprex is not recommended for use in those under six years of age.
• The dose for older persons should be chosen carefully, because this group is more likely to have decreased renal function.
• Codeprex is classified as Pregnancy Category C. It should be used during pregnancy and lactation only if the benefit justifies the potential risk to the fetus.