Metoprolol vs. Clonidine

Metoprolol is a beta-blocker that blocks action of the sympathetic nervous system and is used to treat conditions such as high blood pressure, heart pain, abnormal heart rhythms, congestive heart failure, hyperthyroidism, and some neurologic conditions. It is also used to prevent migraine headaches.

Clonidine is an alpha-2 adrenergic agonist used to treat high blood pressure. It acts by stimulating receptors on nerves in the brain, reducing transmission of messages to other parts of the body. This results in a slower heart rate and reduced blood pressure. Clonidine is also used off-label to treat symptoms of narcotic withdrawal, nicotine withdrawal, diabetes-associated diarrhea, diabetic neuropathy, hot flashes associated with menopause, and as an adjunct to manage severe cancer-related pain.

QUESTION

What are the side effects of metoprolol and clonidine?

Metoprolol

Metoprolol is generally well tolerated. Side effects include:

• Abdominal cramps
• Diarrhea
• Constipation
• Fatigue
• Insomnia
• Indigestion
• Nausea
• Depression
• Dreaming
• Memory loss
• Fever
• Impotence
• Lightheadedness
• Low blood pressure
• Decreased exercise tolerance
• Increased triglycerides
• Bronchospasm
• Cold extremities
• Sore throat
• Shortness of breath or wheezing

Possible serious adverse effects include:

• Slow heart rate
• Raynaud’s phenomenon
• Hepatitis
• Increased insulin resistance

Metoprolol can aggravate breathing difficulties in patients with asthma, chronic bronchitis, or emphysema.

WARNING:

• In patients with existing slow heart rates and heart blocks, metoprolol can cause dangerously slow heart rates and 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 worsen angina and occasionally precipitate heart attacks. If discontinuation is necessary, dosage should be reduced gradually over several weeks.
• High-dose extended release metoprolol in patients undergoing non-cardiac surgery is associated with bradycardia, hypotension, stroke, and death. However, long-term therapy should not be routinely withdrawn prior to major surgery.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 anesthesia and surgery.

Clonidine

The most common side effects are:

Other side effects include:

• Skin redness
• Itching
• Impotence
• Darkening of skin
• Decreased sexual desire
• Ejaculatory dysfunction

Possible serious side effects include:

• Severe rebound high blood pressure
• Severe low blood pressure
• Slow heart rate
• Withdrawal symptoms
• Depression
• Angioedema
• Severe allergic reactions
• Slow heart rate
• Fainting
• Abnormal heart conduction

Severe rebound hypertension can occur following withdrawal from clonidine. This reaction is more likely if clonidine is stopped suddenly without a gradual dose reduction.

Symptoms of severe rebound high blood pressure can include:

Slowly reducing the dose of this medication over several days will prevent these symptoms.

What is the dosage of metoprolol vs. clonidine?

Metoprolol

• 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 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 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.

Clonidine

• 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?

Metoprolol

• Calcium channel blockers and digoxin can lower blood pressure and heart rate when administered together with metoprolol.
• Metoprolol can mask early warning symptoms of low blood sugar and should be used with caution in patients receiving treatment for diabetes.
• Fluoxetine can increase blood levels of metoprolol and increase side effects.

Clonidine

This drug can increase the sedating effects of other medications that cause sedation. Such drugs include:

• Narcotic pain relievers
• Barbiturates
• Sedatives
• Ethanol

Tricyclic antidepressants 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, digoxin, diltiazem, and verapamil.

Abnormal heart rhythms can occur with the combination of clonidine and verapamil.

Cyclosporine concentrations in the blood can increase when clonidine is begun. This interaction could result in kidney damage from increased levels of cyclosporine.

Nonsteroidal anti-inflammatory drugs can reduce the antihypertensive effects of clonidine.

Cocaine, pseudoephedrine, phenylephrine, and phenylpropanolamine can reverse the blood pressure lowering effects of clonidine.

Are metoprolol and clonidine safe to use while pregnant or breastfeeding?

Metoprolol

• 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.

Clonidine

• 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.

From

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Summary

Metoprolol and clonidine are used to treat high blood pressure. Metoprolol is a beta-blocker also used to treat heart pain, abnormal heart rhythms, congestive heart failure, hyperthyroidism, and some neurologic conditions, and to prevent migraine headaches. Clonidine is an alpha-2 adrenergic agonist used off-label to treat symptoms of narcotic withdrawal, nicotine withdrawal, diabetes-associated diarrhea, diabetic neuropathy, hot flashes associated with menopause, and as an adjunct to manage severe cancer-related pain.