Many prescription and nonprescription medicines can cause generalized weakness and fatigue. The degree of weakness and fatigue caused by a certain medicine will vary from person to person.

Medicines that may cause weakness or fatigue include:

• Antianxiety medicines, such as Librium, Valium, Xanax, or Ativan.
• Antihistamines, such as Benadryl or Chlor-Trimeton.
• High blood pressure medicines (antihypertensives), such as Inderal, Lopressor, verapamil, Catapres, or reserpine.
• Diuretics, such as hydrochlorothiazide, Diuril, Dyazide, Lasix, or spironolactone.
• Pain medicine, such as codeine, Darvon, or Vicodin.
• Steroids, such as prednisone, methylprednisolone, or dexamethasone.
• Tricyclic antidepressants, such as amitriptyline, Pamelor, or Tofranil.
• Statins, such as lovastatin (Mevacor), pravastatin (Pravachol), or simvastatin (Zocor).

If you think a prescription or nonprescription medicine may be causing your weakness or fatigue, call your doctor.