From the Guidelines
Diltiazem can cause several side effects, including hypotension, bradycardia, and precipitation of heart failure, as noted in the 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1.
Common Side Effects
The most frequent side effects of diltiazem include:
- Hypotension (low blood pressure)
- Bradycardia (slow heart rate)
- Precipitation of heart failure
- Dizziness
- Headache
- Peripheral edema (swelling in the ankles and feet)
Serious Side Effects
More concerning side effects of diltiazem include:
- Heart block
- Liver dysfunction
- Skin rashes
- Gingival hyperplasia (overgrowth of gum tissue)
Special Considerations
Elderly patients are particularly susceptible to the hypotensive effects of diltiazem, as noted in the 2013 ACCF/AHA focused update incorporated into the ACCF/AHA 2007 guidelines for the management of patients with unstable angina/non-ST-elevation myocardial infarction 1.
Recommendations
Diltiazem should be used with caution in patients with heart failure, pre-excited AF or flutter, or rhythms consistent with VT, and should only be given to patients with narrow-complex tachycardias (regular or irregular) 1. In addition, diltiazem can have a detrimental effect on mortality rates in patients with LV dysfunction, as noted in the 2013 ACCF/AHA focused update 1. The 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia also recommends that diltiazem be avoided in patients with advanced heart failure and in patients with heart block or sinus node dysfunction in the absence of pacemaker therapy 1.
From the FDA Drug Label
ADVERSE REACTIONS Serious adverse reactions have been rare in studies carried out to date, but it should be recognized that patients with impaired ventricular function and cardiac conduction abnormalities usually have been excluded In domestic placebo-controlled angina trials, the incidence of adverse reactions reported during diltiazem hydrochloride therapy was not greater than that reported during placebo therapy. The following represent occurrences observed in clinical studies of angina patients. In many cases, the relationship to diltiazem hydrochloride has not been established The most common occurrences from these studies, as well as their frequency of presentation, are edema (2.4%), headache (2.1%), nausea (1.9%), dizziness (1.5%), rash (1.3%), and asthenia (1. 2%) In addition, the following events were reported infrequently (less than 1%): Cardiovascular: Angina, arrhythmia, AV block (first-degree), AV block (second- or third-degree – see WARNINGS, Cardiac Conduction), bradycardia, bundle branch block, congestive heart failure, ECG abnormality, flushing, hypotension, palpitations, syncope, tachycardia, ventricular extrasystoles Nervous System: Abnormal dreams, amnesia, depression, gait abnormality, hallucinations, insomnia, nervousness, paresthesia, personality change, somnolence, tremor Gastrointestinal: Anorexia, constipation, diarrhea, dysgeusia, dyspepsia, mild elevations of alkaline phosphatase, SGOT, SGPT, and LDH (see WARNINGS, Acute Hepatic Injury), thirst, vomiting, weight increase elevation, dry mouth, dyspnea, epistaxis, eye irritation, hyperglycemia, hyperuricemia, impotence, muscle cramps, nasal congestion, nocturia, osteoarticular pain, polyuria, sexual difficulties, tinnitus The following postmarketing events have been reported infrequently in patients receiving diltiazem hydrochloride tablets: acute generalized exanthematous pustulosis, allergic reactions, alopecia, angioedema (including facial or periorbital edema), asystole, erythema multiforme (including Stevens-Johnson syndrome, toxic epidermal necrolysis), extrapyramidal symptoms, gingival hyperplasia, hemolytic anemia, increased bleeding time, leukopenia, photosensitivity (including lichenoid keratosis and hyperpigmentation at sun-exposed skin areas), purpura, retinopathy, myopathy, and thrombocytopenia
The common side effects of Diltiazem include:
- Edema (2.4%)
- Headache (2.1%)
- Nausea (1.9%)
- Dizziness (1.5%)
- Rash (1.3%)
- Asthenia (1.2%) The less common side effects include:
- Cardiovascular events such as angina, arrhythmia, and hypotension
- Nervous system events such as abnormal dreams, depression, and insomnia
- Gastrointestinal events such as anorexia, constipation, and diarrhea
- Other events such as alopecia, angioedema, and photosensitivity 2
From the Research
Diltiazem Side Effects
- Diltiazem, a non-dihydropyridine calcium channel blocker, can cause side effects such as conduction disturbances and heart failure in patients with underlying cardiac disease 3.
- The use of diltiazem may be associated with a decreased risk of heart failure hospitalization, but also with an increased risk of all-cause mortality compared to beta blockers 4.
- Diltiazem can cause sinus arrest or severe sinus bradycardia, especially when used in combination with beta-blockers 5.
- Diltiazem has been shown to improve cardiac performance and reduce systemic vascular resistance, but may also cause a decrease in heart rate 6.
- As a calcium channel blocker, diltiazem is commonly used in the treatment of hypertension, but may be less effective than other agents in preventing heart failure and myocardial infarction 7.
Common Side Effects
- Conduction disturbances
- Heart failure
- Sinus arrest or severe sinus bradycardia
- Decrease in heart rate
- Peripheral edema (less common with newer agents)
Special Considerations
- Patients with underlying cardiac disease should be monitored closely for signs of conduction disturbances and heart failure 3.
- The combination of diltiazem and beta-blockers should be used with caution due to the increased risk of sinus arrest or severe sinus bradycardia 5.
- Diltiazem may be suitable for patients with comorbid Raynaud's syndrome, isolated systolic hypertension, or angina pectoris 7.