Mechanism of Action
Hydrocodone is a semisynthetic narcotic antitussive and analgesic with multiple actions qualitatively similar to those of codeine. The precise mechanism of action of hydrocodone and other opiates is not known; however, hydrocodone is believed to act directly on the cough center. In excessive doses, hydrocodone will depress respiration. Hydrocodone can produce miosis, euphoria, and physical and physiological dependence.
Pseudoephedrine hydrochloride is an orally active sympathomimetic amine and exerts a decongestant action on the nasal mucosa. Pseudoephedrine hydrochloride is recognized as an effective agent for the relief of nasal congestion due to the common cold. Pseudoephedrine produces peripheral effects similar to those of ephedrine and central effects similar to, but less intense than, amphetamines. It has the potential for excitatory side effects.
Systemic exposure (in terms of peak plasma concentrations and area under plasma concentration versus time curve) of hydrocodone bitartrate and pseudoephedrine hydrochloride after single-dose administration of 5 mg hydrocodone and 60 mg pseudoephedrine are equivalent to respective reference solutions of 5 mL hydrocodone bitartrate (5 mg/5 mL) and 5 mL pseudoephedrine hydrochloride (60 mg/5 mL).
Hydrocodone had a mean (SD) peak plasma concentration of 10.6 (2.63) ng/mL at 1.4 (0.55) hours. The mean plasma half-life of hydrocodone is approximately 4.9 hours. Pseudoephedrine had a mean (SD) peak plasma concentration of 212 (46.2) ng/mL at 1.8 (0.56) hours. The mean plasma half-life of pseudoephedrine is approximately 5.6 hours.
Pseudoephedrine is primarily excreted unchanged in the urine as unchanged drug with the remainder apparently being metabolized in the liver. Therefore, pseudoephedrine may accumulate in patients with renal impairment.
Efficacy studies were not conducted with REZIRA Oral Solution. Efficacy of REZIRA Oral Solution is based on demonstration of bioequivalence to the individual reference products [see Pharmacokinetics].
Last reviewed on RxList: 8/2/2011
This monograph has been modified to include the generic and brand name in many instances.
Additional Rezira Information
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