Azelnidipine (Calblock) is a calcium channel blocker indicated for the treatment of hypertension, with azelnidipine as its main active ingredient. As a prescription drug, its administration must be in strict compliance with the physician’s instructions, and full understanding of its potential adverse reactions and special precautions is required.

Adverse Reactions of Azelnidipine (Calblock)

Common Adverse Reactions

(1) Psychoneurological system: Headache and a heavy sensation in the head are common; dizziness, unsteady gait, lightheadedness and somnolence occur occasionally; abnormal sensations (e.g., a floating feeling, dysphoria) have also been reported.

(2) Cardiovascular system: Palpitations, flushing and a sensation of warmth are common.

(3) Digestive system: Gastric discomfort, nausea, abdominal pain and diarrhea are common; gingival hyperplasia, stomatitis and constipation occur occasionally.

(4) Hepatic system: Elevations in alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) are common; elevations in alkaline phosphatase (ALP), total bilirubin, gamma-glutamyl transpeptidase (γ-GTP) and abnormal liver function occur occasionally.

(5) Renal and urinary systems: Elevations in blood urea nitrogen (BUN), increased urinary hyaline casts, elevated creatinine and frequent micturition occur occasionally.

Severe Adverse Reactions

(1) Hepatic dysfunction and jaundice: Hepatic dysfunction accompanied by elevated levels of AST, ALT, γ-GTP and other indicators may occur, and even jaundice in severe cases. Liver function should be monitored during medication.

(2) Cardiac conduction block: Atrioventricular block, sinus arrest, bradycardia and other disorders may be induced, accompanied by symptoms such as dizziness and unsteady gait.

(3) Severe hypersensitivity reactions: This drug is contraindicated in patients with a history of hypersensitivity to any of the drug ingredients.

(4) Myocardial infarction, heart failure and cardiac arrhythmia: Although the causal relationship has not been fully confirmed, there have been reports of such events occurring during the treatment period.

(5) Excessive hypotension: Excessive blood pressure reduction may be induced, leading to symptoms such as dizziness and fatigue. Extra caution is required when changing body posture abruptly, working at heights or driving a vehicle.

Precautions for Azelnidipine (Calblock)

Conditions Requiring Cautious Administration

(1) Drug withdrawal: Do not discontinue the drug abruptly. If discontinuation is necessary, the dosage should be gradually reduced under the guidance of a physician to avoid rebound hypertension and subsequent exacerbation of symptoms.

(2) Administration and diet: Food may affect the absorption of the drug, and oral administration after breakfast is recommended. Concurrent consumption with grapefruit juice is strictly prohibited, as grapefruit juice can cause a several-fold significant increase in the peak plasma concentration (Cmax) and total exposure (AUC) of azelnidipine.

Dose Adjustment for Special Populations

(1) Geriatric patients: Treatment should be initiated at a low dose (e.g., 8 mg or lower) with cautious administration, so as to avoid the risk of cerebral infarction induced by excessive hypotension.

(2) Patients with severe renal impairment: Antihypertensive treatment may lead to further deterioration of renal function, and close monitoring is required.

(3) Patients with severe hepatic impairment: Sufficient clinical data are lacking, and the benefits and risks must be weighed prior to administration.

(4) Lactating women: The drug is excreted in the milk of lactating rats. The use in lactating women should be decided by weighing the necessity of treatment against the benefits of breastfeeding.

(5) Pediatric population: Efficacy data for pediatric use have not been established yet.

Drug Interactions

(1) Concomitant use with other antihypertensive drugs: The antihypertensive effect may be potentiated, leading to hypotension; dosage adjustment should be noted.

(2) Concomitant use with some statins: Co-administration with simvastatin may cause a significant elevation in the plasma concentration of statins and increase the risk of muscular toxicity (e.g., rhabdomyolysis), while the interaction with atorvastatin or pravastatin is mild.

(3) Concomitant use with digoxin: A mild elevation in the plasma concentration of digoxin may occur, and the digoxin level should be monitored during combined administration.