Generic name: Tacrine hydrochloride.

Cognex is a cholinesterase inhibitor. It works by balancing certain chemicals in the brain. 

Quick Facts About Cognex


Used to treat mild to moderate Alzheimer’s disease.

Cognex Dosage

Take exactly as prescribed; do not change the dose unless instructed by your doctor. Abruptly stopping the treatment can cause the condition to worsen; increasing dose also causes serious problems. More effective if taken at regular intervals, between meals. If irritating to the stomach, doctor may prescribe taking Cognex with meals.

  • Usual adult dose: 10 milligrams taken 4 times per day, for at least 6 weeks. Doctor may increase up to 20 milligrams 4 times per day. Restarting Cognex therapy — 10 milligrams taken 4 times per day for 6 weeks.
  • Usual child dose: not prescribed for children.
  • Missed dose: take as soon as possible, unless within 2 hours of next dose. In that case, do not take missed dose; go back to regular schedule. Do not double doses.

Cognex Side Effects

Overdose symptoms:

collapse, convulsions, extreme muscle weakness (possibly ending in death if breathing muscles affected), low blood pressure, nausea, salivation, slowed heart rate, sweating, vomiting. If you suspect an overdose, immediately seek medical attention.

More common side effects: abdominal pain, abnormal thinking, agitation, anxiety, chest pain, clumsiness or unsteadiness, confusion, constipation, coughing, depression, diarrhea, dizziness, fatigue, flushing, frequent urination, gas, headache, inflamed nasal passages, insomnia, indigestion, liver function disorders, loss of appetite, muscle pain, nausea, rash, sleepiness, upper respiratory infection, urinary tract infection, vomiting, weight loss.

Less common Cognex side effects: back pain, hallucinations, hostile attitude, purple or red spots on the skin, skin discoloration, tremor, weakness.


Inform your doctor before combining Cognex with:

antispasmodic drugs such as Bentyl and Cogentin; Bethanechol chloride (Urecholine); Cimetidine (Tagamet): Theophylline (Theo-Dur).

No known food/other substance interactions. 

Special Cautions

If pregnant or planning to become pregnant, inform your doctor immediately. Not known if Cognex appears in breast milk.

No special precautions apply to seniors.

Not prescribed for children.

  • Do not take if there is sensitivity to or allergic reaction to Cognex.
  • Discuss any medical problems of the person you are caring for with the doctor before starting Cognex therapy, especially any history of asthma, heart disorders, liver disease, or stomach ulcers.
  • Monitor for nausea, vomiting, loose stools, or diarrhea at the start of therapy. Later, monitor for rash, yellowing of the eyes and skin, or changes in the color of the stool.
  • Notify doctor before any surgery, including dental, that the person is being treated with Cognex.
  • Can cause seizures and difficulty urinating.
  • Doctor will schedule weekly blood tests to monitor liver function for the first 18 weeks of therapy, then every 3 months thereafter. If dose increased, weekly monitoring will resume.

Note: provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Cognex side effects, please contact your healthcare provider.