Metoprolol vs. clonidine: What’s the difference?
- Metoprolol and clonidine are used to treat high blood pressure (hypertension).
- Metoprolol is also used to treat heart pain (angina), congestive heart failure, hyperthyroidism, abnormal heart rhythms, some neurologic conditions, and to prevent migraine headaches.
- Brand names for metoprolol include Lopressor and Toprol XL.
- Brand names for clonidine include Catapres and Catapres-TTS.
- Metoprolol and clonidine belong to different drug classes. Metoprolol is a beta-blocker (beta-adrenergic blocking agent) and clonidine is an alpha-2 adrenergic agonist (central alpha agonist).
- Side effects of metoprolol and clonidine that are similar include constipation, fatigue/tiredness, or impotence.
- Side effects of metoprolol that are different from clonidine include abdominal cramps, diarrhea, insomnia, indigestion, nausea, depression, dreaming, memory loss, fever, lightheadedness, low blood pressure, decreased exercise tolerance, increased triglycerides, bronchospasm, cold extremities, sore throat, shortness of breath, or wheezing.
- Side effects of clonidine that are different from metoprolol include lethargy, drowsiness, dry mouth, headache, dizziness, weakness, skin redness, itching, darkening of skin, decreased sexual desire, and ejaculatory dysfunction.
What are metoprolol and clonidine?
Metoprolol is a beta-blocker (beta-adrenergic blocking agent) that blocks the action of the sympathetic nervous system (a portion of the involuntary nervous system) and is used to treat high blood pressure (hypertension), heart pain (angina pectoris), abnormal heart rhythms, congestive heart failure, hyperthyroidism, and some neurologic conditions. Metoprolol is also used to prevent migraine headaches.
Clonidine is an alpha-2 adrenergic agonist (central alpha agonist) used to treat high blood pressure (hypertension). It acts by stimulating receptors on nerves in the brain that reduces the transmission of messages from nerves in the brain to nerves in other areas of the body. As a result, it slows heart rate and reduces blood pressure. Clonidine is also used off-label to treat symptoms of narcotic withdrawal, nicotine withdrawal, diabetes-associated diarrhea, diabetic neuropathy (nerve damage), hot flashes associated with menopause, and as an adjunct to manage severe cancer-related pain.
Salt and sodium are the same.
What are the side effects of metoprolol and clonidine?
Metoprolol is generally well tolerated. Side effects include:
- Abdominal cramps
- Memory loss
- Low blood pressure
- Decreased exercise tolerance
- Increased triglycerides
- Cold extremities
- Sore throat
- Shortness of breath or wheezing
Possible serious adverse effects include:
- In patients with existing slow heart rates (bradycardias) and heart blocks (defects in the electrical conduction of the heart), metoprolol can cause dangerously slow heart rates, and even shock. Metoprolol reduces the force of heart muscle contraction and can aggravate symptoms of heart failure. In patients with coronary artery disease, abruptly stopping metoprolol can suddenly worsen angina, and occasionally precipitate heart attacks. If it is necessary to discontinue metoprolol, its dosage should be reduced gradually over several weeks.
- Initiation of high-dose extended release metoprolol in patients undergoing non-cardiac surgery is associated with bradycardia (slow heart rate), hypotension, stroke, and death. However, long-term therapy with metoprolol should not be routinely withdrawn prior to major surgery. Impaired ability of the heart to respond to reflex adrenergic stimuli may increase the risks of general anesthesia and surgery.
The most common side effects are:
Other side effects include:
Possible serious side effects include:
- Severe rebound high blood pressure
- Severe low blood pressure
- Slow heart rate
- Withdrawal symptoms
- Severe allergic reactions
- Slow heart rate
- Abnormal heart conduction
Severe rebound hypertension can occur following withdrawal from clonidine. This reaction is more likely to occur if clonidine is stopped suddenly (without a gradual dose reduction).
Symptoms of severe rebound high blood pressure can include:
- Increased salivation
- Heart palpitations
- Muscle pain
- Abdominal pain
Slowly reducing the dose of this medication over several days will prevent these symptoms.
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What is the dosage of metoprolol vs. clonidine?
- Metoprolol should be taken before meals or at bedtime.
- The dose for treating hypertension is 100 to 450 mg daily in single or divided doses.
- Angina is treated with 100 to 400 mg daily in two divided doses.
- Heart attack (acute myocardial infarction) is treated with three 5 mg injections administered 2 minutes apart followed by treatment with 50 mg oral metoprolol every 6 hours for 48 hours. After 48 hours, patients should receive 100 mg orally twice daily for at least 3 months.
- The dose for congestive heart failure is 25 mg/daily initially. Then the dose is increased every 2 weeks to reach a target dose of 200 mg/daily orally.
- Hyperthyroidism is treated with 25 to 30 mg by mouth every 6 hours.
- The usual oral adult dose is 0.1 to 0.3 mg twice daily.
- The maximum oral dose is 2.4 mg daily.
- Topical patches should be applied to an area of hairless skin on the upper arm or torso once every 7 days.
- When applying a new topical patch, a different area of skin should be used.
What drugs interact with metoprolol and clonidine?
- Calcium channel blockers and digoxin (Lanoxin) can lower blood pressure and heart rate to dangerous levels when administered together with metoprolol.
- Metoprolol can mask the early warning symptoms of low blood sugar (hypoglycemia) and should be used with caution in patients receiving treatment for diabetes.
- Fluoxetine (Prozac) can increase blood levels of metoprolol by reducing breakdown of metoprolol, and increase the side effects from metoprolol.
This drug can increase the sedating effects of other medications that cause sedation. Such drugs include:
- Narcotic pain relievers
- Sedatives such as alprazolam (Xanax) and clonazepam (Klonopin)
Tricyclic antidepressants — for example, amitriptyline (Elavil, Endep), imipramine (Tofranil), desipramine (Norpramin), and clomipramine (Anafranil) — can block the blood pressure lowering effects of clonidine. This may cause blood pressure to rise.
Since this drug can reduce heart rate, it should be used cautiously in persons who are receiving any other medication that lowers heart rate such as beta-blockers, for example:
- atenolol (Tenormin)
- metoprolol (Lopressor)
- propranolol (Inderal)
- digoxin (Lanoxin)
- diltiazem (Cardizem)
- verapamil (Calan Covera HS)
Abnormal heart rhythms can occur with the combination of clonidine and verapamil.
Cocaine, pseudoephedrine, phenylephrine, and phenylpropanolamine also can reverse the blood pressure lowering effects of clonidine.
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Are metoprolol and clonidine safe to use while pregnant or breastfeeding?
- Safe use of metoprolol during pregnancy has not been established.
- Small quantities of metoprolol are excreted in breast milk and may potentially cause adverse effects in the infant.
- There are no adequate studies of this drug in pregnancy.
- It is excreted into breast milk and potentially could cause adverse effects in the infant.