Sex-based differences in drug activity.

Physiologic differences between men and women affect drug activity, including pharmacokinetics and pharmacodynamics. Pharmacokinetics in women is affected by lower body weight, slower gastrointestinal motility, less intestinal enzymatic activity, and slower glomerular filtration rate. Because of delayed gastric emptying, women may need to extend the interval between eating and taking medications that must be absorbed on an empty stomach. Other physiologic differences may affect medication dosages. For example, because renal clearance is slower in women, some renally-excreted medications, such as digoxin, may require a dosage adjustment. Pharmacodynamic differences in women include greater sensitivity to and enhanced effectiveness of beta blockers, opioids, selective serotonin reuptake inhibitors, and typical antipsychotics. Additionally, women are 50 to 75 percent more likely than men to experience an adverse drug reaction. Because women are prone to torsades de pointes, medications known to prolong the QT interval should be used with caution. Women should receive lower dosages of digoxin and have lower serum concentration targets than men because of higher mortality rates.