Didanosine

Structural formula
General
Non-proprietary name	Didanosine
other names	2 ', 3'-dideoxyinosine ddI 9 - [(2 R , 5 S ) -5- (hydroxymethyl) oxolan-2-yl] -3 H -purin-6-one
Molecular formula	C 10 H 12 N 4 O 3
Brief description	white to almost white, crystalline powder
External identifiers / databases
CAS number 69655-05-6 EC number 614-994-4 ECHA InfoCard 100.129.182 PubChem 50599 ChemSpider 45864 DrugBank DB00900 Wikidata Q422606
Drug information
ATC code	J05 AF02
Drug class	Antiviral , nucleoside reverse transcriptase inhibitors
Mechanism of action	Competitive inhibition of reverse transcriptase
properties
Molar mass	236.23 g · mol -1
Physical state	firmly
Melting point	160-163 ° C
solubility	slightly soluble in water, slightly soluble in dimethyl sulfoxide , slightly soluble in ethanol 96% and methanol
safety instructions
Please note the exemption from the labeling requirement for drugs, medical devices, cosmetics, food and animal feed GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
Toxicological data	> 2000 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Didanosine (ddl for short, trade name Videx ^® ; manufacturer Bristol-Myers Squibb ) is a drug for the treatment of HIV-1 infected patients as part of a combination antiretroviral therapy .

Didanosine belongs to the substance class of nucleoside reverse transcriptase inhibitors .

pharmacology

In vitro studies have shown that didanosine inhibits the replication of HIV at therapeutic concentrations. The substance showed only minor effects on stem cells of the bone marrow. After diffusion into the cell, it is converted into dideoxyadenosine triphosphate (ddATP), which is the biologically active form of the active ingredient that competes with the physiological substrate deoxyadenosine triphosphate (dATP). No cross-resistance to zidovudine-resistant viruses was found.

Pharmacokinetics

Didanosine is not stable in the acidic environment of the stomach. The first preparation of didanosine (Videx ®), approved in Germany in 1992, was a chewable tablet that contained additives that acted as a buffer against gastric acid. The acid buffer increases the risk of interactions with other drugs. In 2000, didanosine was approved in the form of enteric coated hard capsules (enteric coated - EC), which no longer contain an acid buffer and are therefore better tolerated. Didanosine is present in the hard capsules as granules, which didanosine only release in the higher pH range of the small intestine.

Since didanosine absorption is reduced by taking it with food, the hard capsules should also be taken on an empty stomach (at least 2 hours before or 2 hours after eating).

The average elimination half-life of didanosine is approximately 1.4 hours. Approx. 20% of the dose is found in the urine after oral administration. The half-life is significantly longer in patients with impaired renal function.

clinic

Didanosine is one of the first NRTIs . Due to its side effects and mitochondrial toxicity, it is no longer used in the usual initial combinations of antiretroviral therapy, but only in rare cases as a later treatment option (second-line combination).

Side effects

The most common are gastrointestinal side effects (diarrhea in more than 10% of patients, nausea and vomiting in up to 10%). Depending on the dose, pancreatitis can occur (1–7%), which can be fatal. Simultaneous administration with other substances that can cause pancreatitis should therefore be avoided (e.g. ribavirin ). Headache and peripheral neurological symptoms such as neuropathy are common (1–10%).

Interactions with other drugs

Based on interactions, didanosine and a. not to be taken with stavudine , tenofovir , allopurinol, or ribavirin . Consumption with food reduces bioavailability.

Web links

• AIDSMeds.com

Individual evidence

1. ↑ ^{a b c} DIDANOSINE CRS data sheet (PDF) at EDQM , accessed on April 29, 2009.
2. ^ Entry on didanosine in the DrugBank of the University of Alberta .
3. ↑ Data sheet 2 ′, 3′-Dideoxyinosine from Sigma-Aldrich , accessed on April 29, 2011 ( PDF ).

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !