Extended release

L. Krywczynski and D. P. Brozyna, Extended-release Dosage Forms, CRC Press, Inc., Boca Raton, Fla., 1987, pp. 1—19. 

Procardia XL. Procardia XL extended-release capsules, marketed by Pfizer Labs Division of Pfizer, Inc., contain nifedipine [21829-25-4] a calcium channel blocker of mol wt 346.3. The extended release tablet is formulated as a once-a-day controlled release capsule for oral adrninistration dehvering either 30, 60, or 90 mg nifedipine. Procardia XL is indicated for use in the management of vasospastic angina, chronic stable angina, and hypertension (see Cardiovascularagents). 

Plasma dmg concentrations rise at a gradual, controlled rate after dosing, and reach a plateau at approximately 6 h after the first dose with minimal fluctuations over the 24 h dosing interval. Subsequent doses maintain the plasma concentration at this plateau. The extended release tablets taken once daily have reduced by fourfold the fluctuations (ratio of peak to trough plasma concentration) observed with the conventional immediate release Procardia tablets taken three times daily (81). 

The nurse may give lamotrigine without regard to meals. However, it is important to give carbamazepine with meals to decrease gastric upset. The nurse can crush the tablets if the patient has difficulty swallowing. However, it is important not to crush or chew extended-released carbamazepine... 

ADM INI STERI NG DISOPYRAMID E Disopyramide is administered to tiie patient with a full glass of water either 1 hour before or 2 hours after meals. If patients are receiving procainamide or quinidine tiie manufacturer suggests that disopyramide therapy not be started for 6 to 12 hours after tiie last dose of quinidine and 3 to 6 hours after tiie last dose of procainamide When tiie patient is to switch from taking tiie regular capsules to taking extended-release capsules, 6 hours should lapse after tiie last capsule before therapy is begun with tiie extended-release capsules. 

Anorexia, nausea, vomiting, 500-3000 mg/d PO epigastric pain, heartburn, XR (extended release) ... 

BIGUANIDES. The nurse gives metformin two or three times a day with meals. If the patient has not experienced a response in 4 weeks using the maximum dose of metformin, the primary care giver may add an oral sulfonylurea while continuing metformin at the maximum dose. Glucophage XR (metformin extended release) is administered once daily with the evening meal. 

Hydroserpine 2 Tablets—hydrochbrothiazide, reserpine Hyzaar—hydrochlorothiazide, losartan potassium Inderide—hydrochlorotliiazide, propranolol HC1 Inderide LA—hydrochlorotliiazide, propranolol HC1 Lexxel Extended-Release—enalapril maleate, felodipine Lopressor—hydrochlorothiazide, metoprolol Lotensin HCT—hydrochlorothiazide, benazepril Lotrel—amlodopine, benazepril... 

Ibric S, Jovanovic M, Djuric A, Parojcic J, Petrovic SD, Solomun L, Stupor B. Artificial neural networks in the modelling and optimization of aspirin extended release tablets with Eudragit LlOO as matrix substance. Pharm Sci Tech 2003 4 62-70. 

The European Stroke Prevention Study 2 (ESPS-2) trial examined four treatment arms—extended-release dipyridamole (ER-DP) 200 mg twice daily alone, aspirin 25 mg twice daily alone, ER-DP 200 mg twice daily + aspirin 25 mg twice daily, or placebo. In comparison with placebo the overall reduction in stroke risk was 16% with ER-DP alone and 18% with aspirin alone. The combination of ER-DP and aspirin led to a 37% reduction in stroke risk compared to placebo. Compared with aspirin alone, the combination of ER-DP with aspirin reduced the risk of stroke by 23%. 

Any extended release preparation ° CR—controlled-release ° EC—enteric coated ° LA—long-acting ° SR—sustained release 0 TR—time release ° SA—sustained action ° SL—sublingual ° XL—extended length ° XR—extended release... 

Metoprolol P,-Selective No 50-1 00 mg twice daily (once daily for extended-release)... 

Aspirin 25 mg + extended-release dipyridamole 200 mg twice daily daily... 

ER, extended-release FDA, Food and Drug Administration HDL, high-density lipoprotein IR, immediate-release LDL, low-density lipoprotein SR, sustained-release. 

ER, extended release HMC-CoA, 3-hydroxy-3-methyglutaryl coenzyme A LDL, low-density lipoprotein. 

Several different niacin formulations are available niacin immediate-release (IR), niacin sustained-release (SR), and niacin extended-release (ER).28,29 These formulations differ in terms of dissolution and absorption rates, metabolism, efficacy, and side effects. Limitations of niacin IR and SR are flushing and hepatotoxicity, respectively. These differences appear related to the dissolution and absorption rates of niacin formulations and its subsequent metabolism. Niacin IR is available by prescription (Niacor ) as well as a dietary supplement which is not regulated by the FDA.28 Currently, there are no FDA-approved niacin SR products, thus, all SR products are available only as dietary supplements. 

LJ, a 25-year-old-woman with complex partial seizures, presents a prescription to the pharmacy for a triphasic oral contraceptive containing ethinyl estradiol and norgestimate. A review of her medication profile shows that she is taking carbamazepine extended-release 1200 mg/day. Her last refill for this prescription was 2 weeks ago. She reports that she has not had a seizure for a year and that she just became engaged. She is planning to be married in 4 months. 

Galantamine is approved for the treatment of mild to moderate dementia of Alzheimer s disease. It can be dosed once or twice daily (if using the immediate-release tablet or extended-release capsule). The initial dose is 8 mg daily (or 4 mg twice daily) for 4 weeks. If tolerated the dose can be increased if needed to 16 mg daily (or 8 mg twice daily) for at... 

As can be seen in Table 35-7, antidepressants are available in several different dosage forms.13,16-18,29,32 The extended-release... 

Wellbutrin XL No Extended-release tablet 150 300-450 Once daily... 

Effexor XR No Extended-release capsule 37.5-75 75-225 Once daily... 

Depakote ER Extended-release tablet Extended release divalproex may and for maintenance... 

Syrup/suspension/ solution Extended-release/ enteric-coated tablets Faster rate of absorption 100% Delayed absorption 60-90% Faster rate of absorption Delayed absorption 89% of the suspension and less than regular-release tablets Unknown NA Faster rate of absorption than tablets Extended-release 90% of intravenous dose. Delayed-release 81-90% of intravenous dose Delayed absorption with delayed-release tablets valproate is rapidlyconverted to VPA in the stomach, then is rapidly and almost completely absorbed from the Gl tract NA NA... 

Delay in absorption by food Yes No reports of increased rate of absorption with fatty meals (extended-release capsule) Unknown Yes food slows the rate of absorption but not the extent for DVPX Bioavailability not affected by food... 

Ti me to reach peak serum concentrations Distribution 0.5-3 hours (regular-release) 4-12 hours (extended-release) 0.25-1 hours (oral solution) 4.5 hours (regular-release) 1.5 hours (suspension) 3-12 hours (extended-release tablets) 4.1-7.7 hours (extended-release capsules) higher peak concentrations with chewable tablets 4.5 hours (range of 3-13 hours) 1 -4 hours (VPA) 3-5 hours (DVPX single dose) 7-14 hours (DVPX extended-release multiple dosing) 1 -4 hours... 

Divalproex sodium is comprised of sodium valproate and valproic acid. The delayed-release and extended-release formulations are converted in the small intestine into valproic add, which is the systemically absorbed form. It was developed as an antiepileptic drug, but also has efficacy for mood stabilization and migraine headaches. It is FDA-approved for the treatment of the manic phase of bipolar disorder. It is generally equal in efficacy to lithium and some other drugs for bipolar mania. It has particular utility in bipolar disorder patients with rapid cycling, mixed mood features, and substance abuse comorbidity. Although not FDA-approved for relapse prevention, studies support this use, and it is widely prescribed for maintenance therapy. Divalproex can be used as monotherapy or in combination with lithium or an antipsychotic drug.31... 

Venlafaxine extended release, in doses of 75 to 225 mg/day, improves social anxiety, performance, and avoidance behavior with a reduction in disability.61 Treatment with venlafaxine results in response rates similar to those seen with paroxetine.60 Venlafaxine may be effective in SSRI non-responders.62 As with SSRIs, doses should be tapered slowly when discontinuing therapy. Tolerability is similar to that observed in depression trials with venlafaxine extended release. Common side effects are anorexia, dry mouth, nausea, insomnia, and sexual dysfunction. 

---