Nitrendipine is a dihydropyridine

calcium channel blocker Calcium channel blockers (CCB), calcium channel antagonists or calcium antagonists are a group of medications that disrupt the movement of calcium () through calcium channels. Calcium channel blockers are used as antihypertensive drugs, i.e., as ...

. It is used in the treatment of primary (essential) hypertension to decrease blood pressure and can reduce the

cardiotoxicity Cardiotoxicity is the occurrence of heart dysfunction as electric or muscle damage, resulting in heart toxicity. The heart becomes weaker and is not as efficient in pumping blood. Cardiotoxicity may be caused by chemotherapy (a usual example is th ...

of cocaine. It was patented in 1971 and approved for medical use in 1985.

Medical uses

Nitrendipine is given to hypertensive individuals in 20 mg oral tablets every day. This amount is effective in reducing blood pressure by 15–20% within 1–2 hours of administration. With long-term treatments, the dosage may rise to as much as 40 mg/day; in elderly individuals, a lower dosage of up to 5 mg/day may be equally effective (this reduction in drug amount is attributed to decreased liver function or “first pass” metabolism). Once digested, nitrendipine is absorbed into the blood and binds to plasma proteins. The majority (98%) is bound to plasma proteins and 70-80% of its inactive polar metabolites are also bound to plasma proteins. Following hepatic metabolism, 80% of the 20 mg dose can be recovered in the first 96 hours as inactive polar metabolites. The specific

volume of distribution In pharmacology, the volume of distribution (VD, also known as apparent volume of distribution, literally, ''volume of dilution'') is the theoretical volume that would be necessary to contain the total amount of an administered drug at the same c ...

of the drug is 2-6 L/kg. In terms of drug half-life, nitrendipine has a

half-life Half-life (symbol ) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable ato ...

of 12–24 hours. The reported side effects include: headache, flushing, edema and palpitations. These side effects can all be attributed to the

vasodilation Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstriction, ...

effect of this drug.

Mechanism of action

Once nitrendipine is ingested, it is absorbed by the gut and metabolized by the liver before it goes into the systemic circulation and reaches the cells of the

smooth muscles Smooth muscle is an involuntary non-striated muscle, so-called because it has no sarcomeres and therefore no striations (''bands'' or ''stripes''). It is divided into two subgroups, single-unit and multiunit smooth muscle. Within single-unit mus ...

and cardiac muscle cells. It binds more effectively with

L-type calcium channel The L-type calcium channel (also known as the dihydropyridine channel, or DHP channel) is part of the high-voltage activated family of voltage-dependent calcium channel. "L" stands for long-lasting referring to the length of activation. This c ...

s in smooth muscle cells because of its lower

resting membrane potential A relatively static membrane potential which is usually referred to as the ground value for trans-membrane voltage. The relatively static membrane potential of quiescent cells is called the resting membrane potential (or resting voltage), as oppo ...

. The nitrendipine diffuses into the membrane and binds to its high affinity binding site on the inactivated L-type calcium channel that's located in between each of the 4 intermembrane components of the α1 subunit. The exact mechanism of action of nitrendipine is unknown, but it is believed to have important

tyrosine -Tyrosine or tyrosine (symbol Tyr or Y) or 4-hydroxyphenylalanine is one of the 20 standard amino acids that are used by cells to synthesize proteins. It is a non-essential amino acid with a polar side group. The word "tyrosine" is from the Gr ...

and

threonine Threonine (symbol Thr or T) is an amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH form under biological conditions), a carboxyl group (which is in the deprotonated −COO� ...

residues in its binding pocket and its binding interferes with the voltage sensor and gating mechanism of the channel. Thought to have a domain-interface model of binding. In hypertension, the binding of nitrendipine causes a decrease in the probability of open L-type calcium channels and reduces the influx of calcium. The reduced levels of calcium prevent smooth muscle contraction within these muscle cells. Prevention of muscle contraction enables smooth muscle dilation. Dilation of the vasculature reduces

total peripheral resistance Vascular resistance is the resistance that must be overcome to push blood through the circulatory system and create flow. The resistance offered by the systemic circulation is known as the systemic vascular resistance (SVR) or may sometimes be cal ...

, which decreases the workload on the heart and prevents scarring of the heart or heart failure. Nitrendipine has additionally been found to act as an

antagonist An antagonist is a character in a story who is presented as the chief foe of the protagonist. Etymology The English word antagonist comes from the Greek ἀνταγωνιστής – ''antagonistēs'', "opponent, competitor, villain, enemy, riv ...

of the

mineralocorticoid receptor The mineralocorticoid receptor (or MR, MLR, MCR), also known as the aldosterone receptor or nuclear receptor subfamily 3, group C, member 2, (NR3C2) is a protein that in humans is encoded by the ''NR3C2'' gene that is located on chromosome 4q31 ...

, or as an

antimineralocorticoid An antimineralocorticoid, also known as a mineralocorticoid receptor antagonist (MRA or MCRA) or aldosterone antagonist, is a diuretic drug which antagonizes the action of aldosterone at mineralocorticoid receptors. This group of drugs is ofte ...

Stereochemistry

Nitrendipine contains a stereocenter and can exist as either of two

enantiomer In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical ant ...

s. The pharmaceutical drug is a

racemate In chemistry, a racemic mixture, or racemate (), is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates. ...

, an equal mixture of (''R'')- and the (''S'')-forms.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, , S. 204.

References

{{Mineralocorticoidics Antimineralocorticoids Calcium channel blockers Dihydropyridines Nitrobenzenes Carboxylate esters Glycine receptor antagonists Methyl esters Ethyl esters