Diltiazem, sold under the brand name Cardizem among others, is a calcium channel blocker medication used to treat high blood pressure, angina, and certain heart arrhythmias. It may also be used in hyperthyroidism if beta blockers cannot be used. It is taken by mouth or injection into a vein. When given by injection, effects typically begin within a few minutes and last a few hours.Common side effects include swelling, dizziness, headaches, and low blood pressure. Other severe side effects include an overly slow heart beat, heart failure, liver problems, and allergic reactions. Use is not recommended during pregnancy. It is unclear if use when breastfeeding is safe.Diltiazem works by relaxing the smooth muscle in the walls of arteries, resulting in them opening and allowing blood to flow more easily. Additionally, it acts on the heart to prolong the period until it can beat again. It does this by blocking the entry of calcium into the cells of the heart and blood vessels. It is a class IV antiarrhythmic.Diltiazem was approved for medical use in the United States in 1982. It is available as a generic medication. In 2019, it was the 72nd most commonly prescribed medication in the United States, with more than 10 million prescriptions. An extended release formulation is also available. Medical uses
Diltiazem is indicated for:

Stable angina (exercise-induced) – diltiazem increases coronary blood flow and decreases myocardial oxygen consumption, secondary to decreased peripheral resistance, heart rate, and contractility. Variant angina – it is effective owing to its direct effects on coronary dilation.
Motor speech disorders are a class of speech disorders that disturb the bodys natural ability to speak due to neurologic impairments. These neurologic impairments make it difficult for individuals with motor speech disorders to plan, program, control, coordinate, and execute speech productions. Disturbances to the individuals natural ability to speak vary in their etiology based on the integrity and integration of cognitive, neuromuscular, and musculoskeletal activities. Speaking is an act dependent on thought and timed execution of airflow and oral motor / oral placement of the lips, tongue, and jaw that can be disrupted by weakness in oral musculature (dysarthria) or an inability to execute the motor movements needed for specific speech sound production (apraxia of speech or developmental verbal dyspraxia). Such deficits can be related to pathology of the nervous system (central and /or peripheral systems involved in motor planning) that affect the timing of respiration, phonation, prosody, and articulation in isolation or in conjunction. Dysarthria
Dysarthria is  the reduced ability to motor plan volitional movements needed for speech production as the result of weakness/paresis and/or paralysis of the musculature of the oral mechanism needed for respiration, phonation, resonance, articulation, and/or prosody. Apraxia
There are two types of Apraxia. Developmental (or Childhood Apraxia of speech) or acquired Apraxia. Childhood apraxia of speech (CAS) is a neurological childhood speech sound disorder that involves impaired precision and consistency of movements required for speech production without any neuromuscular deficits (ASHA, 2007a, Definitions of CAS section, para. 1).