8 Long-term treatment, and living with cardiovascular diseases
8.3 Issues with medications
Most pharmaceutical drugs will have side effects – unwanted and sometimes unexpected effects, in addition to the medical benefits expected with the drug's use. All prescription drugs are accompanied by an information sheet outlining possible side effects. Such unwanted effects can cause problems with patient compliance: despite being prescribed certain drugs or drug combinations, patients will either not take their drugs or not take them in accordance with the suggested schedule. Sometimes the lack of patient compliance may simply be an issue of the patient forgetting to take their medication.
For [the cholesterol-lowering drug] simvastatin, the evidence is that marginally better lowering of total and LDL cholesterol comes from taking the tablets in the evening than in the morning.
There is an inverse relationship between patient compliance and both number of drugs and number of doses per day, and there can be further loss in compliance when medication regimens are changed. What is really important is that the patient takes the drug reliably, and if that is easier with morning dosing, the extra 10 to 13% reduction in LDL-cholesterol potentially achieved with evening dosing is probably worth foregoing. An evening dose is more easily forgotten.