From the Guidelines
If you experience an allergic reaction to amlodipine, stop taking the medication immediately and seek medical attention, especially if symptoms are severe. Contact your healthcare provider right away to report the reaction and get guidance. Mild symptoms like skin rash or itching may be managed temporarily with over-the-counter antihistamines such as diphenhydramine (Benadryl) 25-50mg every 6 hours as needed until you can see your doctor. For severe reactions including facial swelling, difficulty breathing, or hives spreading across your body, call emergency services (911) immediately as these could indicate anaphylaxis, a life-threatening condition 1, 2. Your doctor will likely switch you to a different class of blood pressure medication, such as an ACE inhibitor, ARB, or beta-blocker, since allergic reactions to one calcium channel blocker often mean you'll react to others in the same class. Allergic reactions occur because your immune system mistakenly identifies the drug as harmful, releasing chemicals that cause inflammation and allergy symptoms. Always wear a medical alert bracelet or carry information about your medication allergies to inform healthcare providers in emergency situations. It's also important to note that patients with a history of anaphylaxis should carry an epinephrine auto-injector and know how to use it properly 3, 4. In case of an anaphylactic reaction, epinephrine is the drug of choice, and its prompt administration is crucial to prevent severe consequences 1, 2. The recommended dose of epinephrine is 0.3 mg intramuscularly for adults and children greater than 30 kg, 0.15 mg intramuscularly for children 15 to 30 kg, or as prescribed by the person’s physician 5. First aid providers should call 9-1-1 immediately when caring for a person with suspected anaphylaxis or a severe allergic reaction. In addition to treating the allergic reaction, it's essential to identify the underlying cause and take steps to prevent future reactions, such as avoiding the offending medication and informing healthcare providers about the allergy. Regular follow-up with a healthcare provider is necessary to monitor the condition and adjust the treatment plan as needed. By taking these steps, individuals with an allergic reaction to amlodipine can minimize the risk of severe consequences and ensure the best possible outcome.
From the FDA Drug Label
Do not use amlodipine besylate if you are allergic to amlodipine (the active ingredient in amlodipine besylate tablets), or to the inactive ingredients.
If you experience an allergic reaction to amlodipine, stop taking the medication and contact your doctor immediately. It is also recommended to seek medical attention at the nearest hospital emergency room or call the Poison Control Center if you took too much amlodipine besylate 6.
From the Research
Allergic Reaction to Amlodipine
- Amlodipine is a calcium channel blocker used to treat hypertension and angina pectoris 7.
- Allergic reactions to amlodipine can occur, including mild, moderate, and severe reactions 8.
- A case study reported a delayed pruritic and erythematous maculopapular skin exanthema after intake of amlodipine, confirmed by a positive lymphocyte transformation test (LTT) 8.
- The LTT also showed positivity to another calcium channel blocker, nifedipine, demonstrating cross-reactivity 8.
Symptoms and Diagnosis
- Symptoms of an allergic reaction to amlodipine may include pruritic and erythematous maculopapular skin exanthema 8.
- A positive LTT can confirm the implication of amlodipine in the reaction 8.
- Other diagnostic methods, such as the Naranjo Adverse Drug Reaction Probability Scale and the Roussel Uclaf Causality Assessment Method, can be used to assess causality in suspected idiosyncratic drug-induced liver injury cases 9.
Treatment and Management
- In case of an allergic reaction to amlodipine, the drug should be discontinued 8, 9.
- Patients who experience late reactions to amlodipine may need to undergo diagnostic tests, such as LTT, to confirm the involvement of the drug 8.
- Alternative treatments, such as other antihypertensive medications, may be prescribed to control blood pressure 10.