Acetaminophen, caffeine, and dihydrocodeine

Drug Interactions: Dihydrocodeine with Other Central Nervous System Depressants: Patients receiving other opioid analgesics, sedatives or hypnotics, muscle relaxants, general anesthetics, centrally acting anti-emetics, phenothiazines or other tranquilizers, or alcohol concomitantly with this combination product may exhibit additive depressant effects on the central nervous system. When such combined therapy is contemplated, the dose of one or both agents should be reduced. Dihydrocodeine with Monoamine Oxidase Inhibitors: Dihydrocodeine, like all opioid analgesics, interacts with monoamine oxidase inhibitors causing central nervous system excitation and hypertension.

Dihydrocodeine with Mixed Agonist/Antagonist Opioid Analgesics: Agonist/antagonist analgesics (i.e., pentazocine, nalbuphine, butorphanol and buprenorphine) may reduce the analgesic effect of this combination product. Acetaminophen Drug Interactions: Chronic and excessive consumption of alcohol may increase the hepatotoxic risk of acetaminophen. The potential for hepatotoxicity with acetaminophen also may be increased in patients receiving anticonvulsants that induce hepatic microsomal enzymes (including phenytoin, barbiturates, and carbamazepine) or isoniazide.

Chronic ingestion of large doses of acetaminophen may slightly potentiate the effects of warfarin- and indandione- derivative anticoagulants. Severe hypothermia is possible in patients receiving acetaminophen concomitantly with phenothiazines. Caffeine Drug Interactions: Caffeine may enhance the cardiac inotropic effects of beta-adrenergic stimulating agents. Co-administration of caffeine and disulfiram may lead to a substantial decrease in caffeine clearance. Caffeine may increase the metabolism of other drugs such as phenobarbital and aspirin. Caffeine accumulation may occur when products or foods containing caffeine are consumed concomitantly with quinolones such as ciprofloxacin.

Pregnancy: Teratogenic Effects – Pregnancy Category C . Animal reproduction studies have not been conducted with TREZIX™ (acetaminophen, caffeine, and dihydrocodeine bitartrate) capsules. It is also not known whether this combination product can cause fetal harm when administered to pregnant women or can affect reproduction capacity in males and females. This combination product should be given to pregnant women only if clearly needed, especially during the first trimester.

Nursing Mothers: Dihydrocodeine bitartrate is secreted into human milk. In women with normal dihydrocodeine metabolism (normal CYP2D6 activity), the amount of dihydrocodeine secreted into human milk is low and dose-dependent. However, some women are ultra-rapid metabolizers of dihydrocodeine. These women achieve higher-than-expected serum levels of dihydrocodeine’s active metabolite, dihydromorphine, leading to higher-than-expected levels of dihydromorphine in breast milk and potentially dangerously high serum dihydromorphine levels in their breastfed infants. Therefore, maternal use of dihydrocodeine can potentially lead to serious adverse reactions, including death, in nursing infants.

The risk of infant exposure to dihydrocodeine and morphine through breast milk should be weighed against the benefits of breastfeeding for both the mother and baby. Caution should be exercised when dihydrocodeine is administered to a nursing woman. If a dihydrocodeine containing product is selected, the lowest dose should be prescribed for the shortest period of time to achieve the desired clinical effect. Mothers using dihydrocodeine should be informed about when to seek immediate medical care and how to identify the signs and symptoms of neonatal toxicity, such as drowsiness or sedation, difficulty breastfeeding, breathing difficulties, and decreased tone, in their baby.

Nursing mothers who are ultra-rapid metabolizers may also experience overdose symptoms such as extreme sleepiness, confusion or shallow breathing. Prescribers should closely monitor mother-infant pairs and notify treating pediatricians about the use of dihydrocodeine-containing products during breastfeeding (See Warnings ). Acetaminophen and caffeine are also excreted in breast milk in small amounts. Because of the potential for serious adverse reactions in nursing infants from this combination product, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.