Generic Name: Chlorthalidone/Clonidine (klor-THAL-i-done/KLON-i-deen)Brand Name: Clorpres

Clorpres is used for:

Treating high blood pressure. It may also be used for other conditions as determined by your doctor.

Clorpres is a combination alpha agonist and diuretic. The alpha agonist works by relaxing blood vessels and decreasing heart rate. The diuretic works by increasing elimination of sodium and water.

Do NOT use Clorpres if:

  • you are allergic to any ingredient in Clorpres , thiazides (eg, hydrochlorothiazide) or related diuretics, or to sulfonamide medicines (eg, sulfamethoxazole)
  • you are unable to urinate

Contact your doctor or health care provider right away if any of these apply to you.

Before using Clorpres :

Some medical conditions may interact with Clorpres . Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

  • if you are pregnant, planning to become pregnant, or are breast-feeding
  • if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
  • if you have allergies to medicines, foods, or other substances
  • if you have a blood vessel disease affecting the brain, heart or blood vessel problems, or you have had a stroke or recent heart attack
  • if you have gout, liver disease, low blood levels of potassium or sodium, kidney problems, the blood disease porphyria, lupus, or if you are vomiting
  • if you have a history of allergy or bronchial asthma
  • if you will be in a hot environment for long periods of time
  • if you are scheduled for surgery

Some MEDICINES MAY INTERACT with Clorpres . Tell your health care provider if you are taking any other medicines, especially any of the following:

  • Beta-blockers (eg, propranolol) or calcium channel blockers (eg, verapamil) because a severe decrease in heart rate or an increase or decrease in blood pressure may occur
  • Tricyclic antidepressants (eg, amitriptyline) because they may decrease Clorpres 's effectiveness
  • Barbiturates (eg, phenobarbital), corticosteroids (eg, cortisone), or narcotics (eg, codeine) because they may increase the risk of Clorpres 's side effects
  • Diazoxide, digitalis glycosides (eg, digoxin), ketanserin, lithium, tubocurarine, or other medicines for high blood pressure because their actions and the risk of their side effects may be increased by Clorpres
  • Insulin, norepinephrine, or oral diabetes medicines (eg, glipizide) because their effectiveness may be decreased by Clorpres

This may not be a complete list of all interactions that may occur. Ask your health care provider if Clorpres may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use Clorpres :

Use Clorpres as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Take Clorpres by mouth with or without food.
  • Take Clorpres on a regular schedule to get the most benefit from it.
  • Continue to use Clorpres even if you feel well. Do not miss any doses.
  • Clorpres may increase the amount of urine or cause you to urinate more often when you first start taking it. To keep this from disturbing your sleep, try to take your dose before 6 pm.
  • If you miss a dose of Clorpres , take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once. If you miss 2 or more doses in a row, contact your doctor.

Ask your health care provider any questions you may have about how to use Clorpres .

Important safety information:

  • Clorpres may cause drowsiness, dizziness, blurred vision, or lightheadedness. These effects may be worse if you take it with alcohol or certain medicines. Use Clorpres with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
  • Do not drink alcohol or use medicines that may cause drowsiness (eg, sleep aids, muscle relaxers) while you are using Clorpres ; it may add to their effects. Ask your pharmacist if you have questions about which medicines may cause drowsiness.
  • Clorpres may cause dizziness, lightheadedness, or fainting; alcohol, hot weather, exercise, or fever may increase these effects. To prevent them, sit up or stand slowly, especially in the morning. Sit or lie down at the first sign of any of these effects.
  • Patients who take medicine for high blood pressure often feel tired or run down for a few weeks after starting treatment. Be sure to take your medicine even if you may not feel "normal." Tell your doctor if you develop any new symptoms.
  • If you experience dry mouth, use sugarless candy or gum, or melt bits of ice in your mouth to help keep your mouth moist.
  • Clorpres may raise your blood sugar. High blood sugar may make you feel confused, drowsy, or thirsty. It can also make you flush, breathe faster, or have a fruit-like breath odor. If these symptoms occur, tell your doctor right away.
  • Clorpres may cause you to become sunburned more easily. Avoid the sun, sunlamps, or tanning booths until you know how you react to Clorpres . Use a sunscreen or wear protective clothing if you must be outside for more than a short time.
  • Tell your doctor or dentist that you take Clorpres before you receive any medical or dental care, emergency care, or surgery.
  • Diabetes patients - Clorpres may affect your blood sugar. Check blood sugar levels closely. Ask your doctor before you change the dose of your diabetes medicine.
  • Lab tests, including blood pressure and blood electrolyte levels, may be performed while you use Clorpres . These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
  • Use Clorpres with caution in the ELDERLY; they may be more sensitive to its effects, especially dizziness.
  • Clorpres should be used with extreme caution in CHILDREN; safety and effectiveness in children have not been confirmed. Also, CHILDREN who are sick and vomiting may be more sensitive to developing withdrawal symptoms.
  • PREGNANCY and BREAST-FEEDING: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Clorpres while you are pregnant. Clorpres is found in breast milk. Do not breast-feed while using Clorpres .

If you stop taking Clorpres suddenly, you may have WITHDRAWAL symptoms. These may include nervousness, agitation, headache, tremor, and rapid increase in blood pressure.

Possible side effects of Clorpres :

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Constipation; dizziness; drowsiness; dry mouth; tiredness.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); agitation; confusion; dark urine; decreased urination; depression; fast, slow, or irregular heartbeat; fever, chills, or sore throat; hallucinations; inability to have sex; increased thirst; joint pain (gout); muscle pain or cramps; nausea; numbness or tingling of the skin; pounding in the chest; rapid breathing; red, swollen, blistered, or peeling skin; restlessness; severe or persistent drowsiness or dry mouth; sluggishness; unusual bruising or bleeding; unusual tiredness or weakness; vision changes; vomiting; weakness; yellowing of the skin or eyes.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may also report side effects at

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center (, or emergency room immediately. Accidental overdose of Clorpres is an increasing cause of poisoning in children 3 years of age and younger. Symptoms may include difficult or slow breathing; drowsiness leading to unresponsiveness or coma; irritability; lightheadedness, especially upon standing; pinpoint pupils; seizures; severe or persistent dizziness; slow or irregular heartbeat; vomiting; weakness.

Proper storage of Clorpres :

Store Clorpres at room temperature, between 59 and 86 degrees F (15 and 30 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. Keep Clorpres out of the reach of children and away from pets.

General information:

  • If you have any questions about Clorpres , please talk with your doctor, pharmacist, or other health care provider.
  • Clorpres is to be used only by the patient for whom it is prescribed. Do not share it with other people.
  • If your symptoms do not improve or if they become worse, check with your doctor.

This information is a summary only. It does not contain all information about Clorpres . If you have questions about the medicine you are taking or would like more information, check with your doctor, pharmacist, or other health care provider.

  • Clorpres Prescribing Information (FDA)
  • Clorpres Concise Consumer Information (Cerner Multum)
  • Clorpres Advanced Consumer (Micromedex) - Includes Dosage Information