Medicine sensitivities

Medicine sensitivities or drug intolerance/sensitivity refers to an inability to tolerate the adverse effects of a medication, generally at therapeutic or subtherapeutic doses. Conversely, a patient is said to be "tolerating" a drug when they can tolerate its adverse effects. It is not to be confused with a drug allergy, which is a form of drug intolerance, but requires an immune-mediated component. It is also not to be confused with drug tolerance ("drug resistance," or tachyphylaxis) which refers to a lack of adverse effects even at higher than average doses. Some instances of drug intolerance are known to result from genetic variations in drug metabolism.

It is a common problem for ME/CFS patients.

Symptom recognition
"Many patients with ME/CFS are sensitive to medications. This is particularly true of any medication that acts on the central nervous system, such as sedating medications: therapeutic benefits can often be achieved at lower-than-standard doses. Patients with ME/CFS might tolerate or need only a fraction of the usual recommended doses for medications. After initial management with lower dosing, one or more gradual increases may be considered as necessary and as tolerated by the patient."
 * The International Consensus Criteria lists sensitivities to food, medications, odors or chemicals as an optional criteria for diagnosis, under the section C. Immune, gastro-intestinal and genitourinary Impairments.
 * 2018, The Centers for Disease Control and Prevention (CDC) website ME/CFS page Monitoring the Use of All Medicines and Supplements gives guidance for healthcare providers on medications for ME/CFS patients.

Prevalence

 * In a 2001 Belgian study, 48.5% of patients meeting the Fukuda criteria and 54.8% of patients meeting the Holmes criteria, in a cohort of 2073 CFS patients, reported new sensitivities to food or drugs.

Learn more

 * Wikipedia