Effects of Food on Bioavailability of Analgesics; Resulting Dosage and Administration Recommendations

Objectives To evaluate currently approved analgesics, that is, opioids, nonsteroidal anti-inflammatory drugs (NSAIDs), anticonvulsants, and serotonin and norepinephrine reuptake inhibitors (SNRIs) used as analgesics, for 1) differences in pharmacokinetic parameters under fed vs fasting conditions and 2) factors involved in dosage recommendations in relation to food. Design Systematic review. Results Food effect on the rate, extent of absorption, or shape of concentration–time profile can alter the onset of action, duration of action, or tolerability of a medication. Based on 79 analgesic products reviewed, food effect dosage recommendations depend on whether an analgesic will be dosed on a regular interval around-the-clock vs on an as-needed basis, the shape of concentration–time profile, steady-state concentrations, the type of meals used in the pharmacokinetic study, and drug administration with regard to food in clinical trials. Overall, most opioids do not have food restriction and are taken without regard to food, with the exception of OPANA products and XTAMPZA ER. For many NSAIDs, food does not affect absorption characteristics, with the exception of ZORVOLEX and CELEBREX. Although NSAIDs are commonly to be taken without regard to food, prescribers recommend administering them with food to reduce their propensity for gastrointestinal adverse events. A larger percentage of anticonvulsants and SNRIs used as analgesics are taken with food to improve their tolerability. Of all analgesic products, seven NSAIDs and six opioids lack food effect information, maybe due to their approval before Food and Drug Administration food effect guidance. Conclusions Overall, because food effects could alter the onset and/or duration of pain relief, analgesic medication should be used as per labeled recommendations for proper pain management.