(RS)-Isradipin Structural Formula V1.svg
Clinical data
Trade namesDynaCirc
  • C
Routes of
ATC code
Legal status
Legal status
Pharmacokinetic data
Protein binding95%
Metabolism100% Hepatic
Elimination half-life8 hours
Excretion70% Renal, 30% Fecal
  • 3-methyl 5-propan-2-yl 4-(2,1,3-benzoxadiazol-4-yl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate
CAS Number
PubChem CID
CompTox Dashboard (EPA)
ECHA InfoCard100.158.721 Edit this at Wikidata
Chemical and physical data
Molar mass371.393 g·mol−1
3D model (JSmol)
  • O=C(OC)\C3=C(\N\C(=C(\C(=O)OC(C)C)C3c1cccc2nonc12)C)C
  • InChI=1S/C19H21N3O5/c1-9(2)26-19(24)15-11(4)20-10(3)14(18(23)25-5)16(15)12-7-6-8-13-17(12)22-27-21-13/h6-9,16,20H,1-5H3 checkY

Isradipine (tradenames DynaCirc, Prescal) is a calcium channel blocker of the dihydropyridine class. It is usually prescribed for the treatment of high blood pressure in order to reduce the risk of stroke and heart attack.

It was patented in 1978 and approved for medical use in 1989.[1]

Medical uses

Isradipine is given as either a 2.5 mg or 5 mg capsule.[2]

Side effects

Common side effects include: [3]

Serious side effects include: [3]

Drug interactions

It is advised that those using Isradipine not take Anzemet (Dolasetron), as both agents can cause a dose-dependent PR interval and QRS complex prolongation.[4]

Itraconazole exhibits a negative inotropic effect on the heart and thus could spur an additive effect when used concomitantly with Isradipine. Onmel/Sporanox also inhibits an important cytochrome liver enzyme (CYP 450 3A4) which is needed to metabolize Isradipine and other Calcium Channel Blockers. This will increase plasma levels of Isradipine and could cause an unintentional overdose of the medication. Caution is advised when administering both agents together.[5]

Tizanidine demonstrates anti-hypertensive effects and should be avoided in patients taking Isradipine due to the possibility of synergism between both medications.[6]

The anti-biotic Rifampin lowered plasma concentrations of Isradipine to below detectable limits.[2]

Cimetidine increased Isradipine mean peak plasma levels. A downward dose adjustment may be necessary with this particular instance of polypharmacy.[2]

Severe hypotension was reported with Fentanyl anesthesia when it was combined with other Calcium Channel Blockers. Even though Isradipine, another Calcium Channel Blocker, has not been used in conjunction with Fentanyl anesthesia in any studies, caution is advised.[2]

Note: There was no significant interaction between Isradipine and Warfarin (Coumadin), Isradipine and Microzide Hydrochlorothiazide, Isradipine and Lanoxin (Digoxin), and Isradipine and Nitrostat (Nitroglycerin).


Symptoms of an Isradipine overdose include:[2]


Isradipine contains a stereocenter and consists of two enantiomers, more precisely atropisomers. This is a racemate, i.e. a 1: 1 mixture of ( R ) - and the ( S ) - Form:[7]

Enantiomers of Isradipine
(R)-Isradipin Structural Formula V1.svg

CAS-Nummer: 84260-63-9
(S)-Isradipin Structural Formula V1.svg

CAS-Nummer: 84260-64-0


  1. ^ Fischer, Jnos; Ganellin, C. Robin (2006). Analogue-based Drug Discovery. John Wiley & Sons. p. 465. ISBN 9783527607495.
  2. ^ a b c d e "Isradipine: Brands, Medical Use, Clinical Data".
  3. ^ a b "Isradipine Side Effects".
  4. ^ "Isradipine and Anzemet Drug Interactions".
  5. ^ "Isradipine and Onmel Drug Interactions".
  6. ^ "Isradipine and Zanaflex Drug Interactions".
  7. ^ Rote Liste Service GmbH (Hrsg.): Rote Liste 2017 – Arzneimittelverzeichnis für Deutschland (einschließlich EU-Zulassungen und bestimmter Medizinprodukte). Rote Liste Service GmbH, Frankfurt/Main, 2017, Aufl. 57, ISBN 978-3-946057-10-9, S. 193.

Further reading