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Diltiazem Hydrochloride XR Side Effects

Generic Name: diltiazem

Note: This page contains information about the side effects of diltiazem. Some of the dosage forms included on this document may not apply to the brand name Diltiazem Hydrochloride XR.

For the Consumer

Applies to diltiazem: oral capsule extended release, oral capsule extended release 12 hr, oral capsule extended release 24 hr, oral tablet, oral tablet extended release

In addition to its needed effects, some unwanted effects may be caused by diltiazem (the active ingredient contained in Diltiazem Hydrochloride XR). In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking diltiazem:

More common:
  • Body aches or pain
  • congestion
  • cough
  • dryness or soreness of the throat
  • fever
  • hoarseness
  • runny nose
  • tender or swollen glands in the neck
  • trouble swallowing
  • voice changes
Less common:
  • Chest pain or discomfort
  • chills
  • diarrhea
  • difficult or labored breathing
  • feeling faint, dizzy, or lightheaded
  • feeling of warmth or heat
  • flushing or redness of the skin, especially on the face and neck
  • general feeling of discomfort or illness
  • headache
  • joint pain
  • loss of appetite
  • muscle aches and pains
  • nausea
  • shivering
  • slow or irregular heartbeat
  • sweating
  • swelling of the hands, ankles, feet, or lower legs
  • tightness in the chest
  • trouble sleeping
  • unusual tiredness or weakness
  • vomiting
Incidence not known:
  • Blistering, peeling, or loosening of the skin
  • itching
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • no heartbeat
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • sores, ulcers, or white spots in the mouth or on the lips

Minor Side Effects

Some of the side effects that can occur with diltiazem may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common:
  • Sneezing
  • stuffy nose
Less common:
  • Acid or sour stomach
  • belching
  • constipation
  • continuing ringing or buzzing or other unexplained noise in the ears
  • degenerative disease of the joint
  • difficulty with moving
  • hearing loss
  • heartburn
  • indigestion
  • lack or loss of strength
  • muscle aching or cramping
  • muscle pains or stiffness
  • pain or tenderness around the eyes and cheekbones
  • rash
  • stomach discomfort, upset, or pain
  • swollen joints
Incidence not known:
  • Hair loss or thinning of the hair

For Healthcare Professionals

Applies to diltiazem: compounding powder, intravenous powder for injection, intravenous solution, oral capsule extended release, oral tablet, oral tablet extended release


The most commonly reported side effects include edema, headache, and dizziness.[Ref]


Very common (10% or more): Peripheral edema (up to 15%)
Common (1% to 10%): Bradycardia, ECG abnormality, first degree atrioventricular (AV) block, bundle branch block, palpitations, edema, asymptomatic/symptomatic hypotension, flushing, vasodilation, extrasystole/ventricular extrasystole, arrhythmia (junctional rhythm/isorhythmic dissociation)
Uncommon (0.1% to 1%): Orthostatic hypotension
Frequency not reported: Angina, AV block (second or third degree), development/aggravation of congestive heart failure, syncope, atrial flutter, sinus pause/arrest, sinus node dysfunction, ventricular arrhythmia, ventricular fibrillation, ventricular tachycardia/tachycardia
Postmarketing reports: Asystole/cardiac arrest, sinoatrial block, vasculitis, vasodilation symptoms (flushing, lower limb edema, sweating), myocardial infarction[Ref]

A patient with Prinzmetal's angina developed asystole after a single, 60 mg dose.

Myocardial infarction was not readily distinguishable from the natural history of the disease.

Vasodilatory events (e.g., peripheral edema, headache, flushing) are dose-related and may be more common in elderly patients.

First degree AV block and sinus bradycardia occurred more frequently with higher doses.[Ref]


Common (1% to 10%): Asthenia, malaise, fatigue, infection, flu syndrome, pain
Frequency not reported: Malaise, tinnitus, thirst[Ref]


Common (1% to 10%): Nausea, dyspepsia, gastric pain, abdominal enlargement, constipation
Uncommon (0.1% to 1%): Vomiting, diarrhea
Rare (0.01% to 0.1%): Dry mouth
Frequency not reported: Gastrointestinal disorder, gingivitis
Postmarketing reports: Gingival hyperplasia[Ref]


Well-documented cases of rashes (as leukocytoclastic vasculitis) have been reported, but a definitive between these events and this drug have not been established.

Lichenoid keratosis and hyperpigmentation occurred in skin exposed to the sun.[Ref]

Common (1% to 10%): Flushing/hot flushes, rash, erythema
Rare (0.01% to 0.1%): Urticaria
Frequency not reported: Petechiae, photosensitivity (lichenoid keratosis), pruritus, hyperpigmentation, hyperhidrosis/sweating
Postmarketing reports: Alopecia, musculocutaneous reactions (simple erythema, desquamative erythema with/without fever), angioneurotic edema, erythema multiforme (Steven-Johnson's syndrome, toxic epidermal necrolysis), exfoliative dermatitis, leukocytoclastic vasculitis, allergic dermatitis, acute generalized exanthematous pustular dermatitis[Ref]


Common (1% to 10%): Pharyngitis, increased cough, bronchitis
Frequency not reported: Dyspnea, epistaxis, sinus/nasal congestion[Ref]

Nervous system

Common (1% to 10%): Myalgia
Frequency not reported: Creatine phosphokinase (CPK) increase, muscle cramp, osteoarticular pain, myopathy, muscle pain, muscle weakness, neck rigidity[Ref]

Dizziness occurred more frequently with higher doses.[Ref]


Common (1% to 10%): Myalgia
Frequency not reported: Creatine phosphokinase (CPK) increase, muscle cramp, osteoarticular pain, myopathy, muscle pain, muscle weakness, neck rigidity[Ref]


Common (1% to 10%): Gout
Frequency not reported: Anorexia, weight increase, hyperglycemia, hyperuricemia[Ref]


Common (1% to 10%): Impotence
Frequency not reported: Nocturia, polyuria, sexual difficulties, albuminuria, crystalluria[Ref]


Common (1% to 10%): Conjunctivitis
Frequency not reported: Amblyopia, eye irritation
Postmarketing reports: Retinopathy[Ref]


Common (1% to 10%): Injection site reactions (e.g., itching, burning)[Ref]


Uncommon (0.1% to 1%): Nervousness, insomnia
Frequency not reported: Abnormal dreams, depression, hallucinations, personality change
Postmarketing reports: Mood changes (including depression)[Ref]


There were rare cases of clinical hepatitis that were reversible with discontinuation of this drug.[Ref]

Uncommon (0.1% to 1%): Increased hepatic enzymes (AST, ALT, LDH, ALP)
Frequency not reported: Clinical hepatitis/hepatitis[Ref]


Postmarketing reports: Hemolytic anemia, increased bleeding time, leukopenia, purpura, thrombocytopenia, lymphadenopathy, eosinophilia[Ref]


Postmarketing reports: Allergic reactions, angioedema (including facial/periorbital edema)[Ref]


Postmarketing reports: Gynecomastia[Ref]


1. "Product Information. Cardizem (diltiazem)." Hoechst Marion-Roussel Inc, Kansas City, MO.

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

3. Cerner Multum, Inc. "Australian Product Information." O 0

4. "Product Information. Dilacor XR (diltiazem)." Aventis Pharmaceuticals, Bridgewater, NJ.

Not all side effects for Diltiazem Hydrochloride XR may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.