Enteric coated preparations

The extended-release formulation (Depakote ER) is 15% less bioavailable than the enteric-coated preparation (Depakote). 

The prodrugs are unstable in the presence of acid and therefore must be administered as an enteric-coated preparation or as a buffered suspension. Pantoprazole is also available in an intravenous formulation. The most commonly reported side effects are diarrhea and headache. Hypergastrinemia has been noted as a reaction to the marked reduction in acid secretion. Gastric carcinoid tumors have developed in rats but not in mice or in human volunteers, even after long-term use. 

Pancrelipase is available in both non-enteric-coated and enteric-coated preparations. Pancrelipase enzymes are rapidly and permanently inactivated by gastric acids. Therefore, non-enteric-coated preparations (eg, Viokase tablets or powder) should be given concomitantly with acid suppression therapy (proton pump inhibitor or H2 antagonist) to reduce acid-mediated destruction within the stomach. Encapsulated formulations contain acid-resistant microspheres (Creon) or microtablets (Pancrease, Ultrase). Enteric-coated formulations are more commonly used because they do not require concomitant acid suppression therapy. 

Relevant quality control should not be restricted to the usual triad of activities of pancreas lipase, a-amylase, and trypsin, but should be extended to the content of colipasc, the activities of the two other lipolytic enzymes present in pancreatine (phospholipase Aj and carboxylester lipase), and the dissolution characteristics of enteric-coated preparations as a function of time and pH (Fig. 16). The availability of such information will certainly contribute to a better tailoring of flic management of maldigestion in the individual patient and to a more appropriate correction of the obligate nonphysio logical route of delivery of these enzyme supplements. 

Murthy, K.S. Enders, N.A. Mahjour, M. Fawzi, M.B. A comparative evaluation of aqueous enteric polymers in capsule coatings. Pharm. Tech. 1986, 10 (Oct), 36 6. Thoma, K. Oschmann, R. Investigations of the permeability of enteric coatings, part 5 pharmaceutical-technological and analytical studies of enteric-coated preparations. Pharmazie 1991, 46, 278-282. 

DIGESTIVE AGENT given by mouth to make up deficiencies in secretions from the pancreatic exocrine gland (e.g. in cystic fibrosis, and following pancreatectomy or chronic pancreatitis), using special enteric-coated preparations. 

Oral pancreatic enzyme supplements are available as a powder, uncoated or coated tablet, capsule, enteric-coated sphere (ECS) and microsphere (ECMS), or enteric-coated microtablet (ECMT) encased in a cellulose or gelatin capsule (Table 39-8). Recommended dosages of microencapsulated enteric-coated products are not necessarily more effective than recommended dosages of the non-enteric-coated enzyme preparations. This is because a lesser quantity of lipase is usually administered at each meal with the enteric-coated preparations. 

Bisacodyl is a laxative that is indicated in short-term treatment of constipation evacuation of colon for rectal and bowel evaluation preparation for delivery or surgery. Bisacodyl is the only diphenyhnethane derivative available in the United States. It is marketed as an enteric-coated preparation (Dulcolax, Correctol, others) and as a suppository for rectal administration. The usual oral daily dose of bisacodyl is 10 to 15 mg for adults and 5 to 10 mg for children 6 to 12 years old. The drug requires hydrolysis by endogenous esterases in the bowel for activation, and so the laxative effects after an oral dose usually are not produced in less than 6 hours taken at bedtime, it will produce its effect the next morning. Suppositories work much more rapidly. 

Bisacodyl is the only diphenylmethane derivative available in the U.S. It is marketed as an enteric-coated preparation (dulcolax, coRREcroL, others) arul as a suppository for rectal administration. The usual oral daily dose of bisacodyl is 10-15 mg for adults and 5-10 mg for children 6-12 years old. 

A. All patients with potentially serious overdose should be observed for at least 6-8 hours before discharge or transfer to a nonmedical (eg, psychiatric) facility. If signs or symptoms of intoxication develop during this time, admission for further observation and treatment is required. Caution Beware of delayed complications from slow absorption of medications (eg, from a tablet concretion or bezoar, or sustained-release or enteric-coated preparations). In these circumstances, a longer period of observation is warranted. If specific dmg levels are determined, obtain repeated serum levels to be certain that they are decreasing as expected. 

Monitor asymptomatic patients for a minimum of 6 hours (longer if an enteric-coated preparation or a massive overdose has been ingested and there is suspicion of a tabiet bezoar). Admit symptomatic patients to an intensive care unit. 

Some of the didanosine preparations (e.g. chewable tablets) are formulated with antacid buffers that are intended to facilitate didanosine absorption by minimising acid-induced hydrolysis in the stomach. These preparations can therefore alter the absorption of other drugs that are affected by antacids (e.g. azole antifungals, quinolone antibacterials, tetracyclines). This interaction may be minimised by separating administration by at least 2 hours. Alternatively, the enteric-coated preparation of didanosine (gastro-resistant capsules) may be used. 

Delavirdine absorption is reduced by the buffered preparation of didanosine. This interaction would not be expected with the enteric-coated preparation of didanosine. Delavirdine does not affect the pharmacokinetics of zidovudine. There is no pharmacokinetic interaction between efavirenz and zidovudine or lamivudine. There is no ciinicaiiy reievant pharmacokinetic interaction between nevirapine and didanosine, iamivudine, stavudine, zaicit-abine or zidovudine. 

Enteric-coated preparation. Enterie-eoated didanosine 400 mg had no significant effect on the pharmacokinetics of fluconazole 200 mg in 14 healthy subjects, and no clinically relevant effect on the pharmacokinetics of itraconazole 200 mg in 25 healthy subjects. Similarly, enteric-coated didanosine 400 mg had no clinically relevant effect on the pharmacokinetics of ketoconazole 200 mg in 24 healthy subjects. Three of the subjects had increased concentrations of ketoconazole with didanosine, but their... 

Itraconazole capsules and ketoconazole depend on stomach acidity for absorption. A raised gastric pH, caused by the antacids in the buffered didanosine formulation appears to reduce itraconazole absorption (consider, Azoles + Antacids , p.215). The didanosine itself appears to have no part to play in this interaction. The enteric-coated preparation of didanosine does not contain any antacids and therefore does not interact. 

The most significant interaction occurs between the buffered preparation of didanosine and itraconazole. Patients should avoid taking both drugs at the same time, but giving the itraconazole at least 2 hours before the didanosine appears to solve any problem. Any possible interaction with ketoconazole can similarly be avoided by giving ketoconazole at least 2 hours before didanosine. Alternatively, the interaction may be avoided by using the enteric-coated preparation of didanosine. 

The bioavailability of enteric-coated preparations of aspirin, diclofenac, and ketoprofen are unaffected by omeprazole, see NSAIDs or Aspirin + Proton pump inhibitors , p.l55. 

Enteric-coated peppermint leaf essential oil capsules may produce anal burning in patients with diarrhea, due to excretion of peppermint oil. Use of enteric-coated capsules has been associated with adverse effects such as rashes, headache, bradycardia, muscle tremors, and ataxia (Mills and Bone 2005). Non-enteric-coated preparations of peppermint leaf essential oil have been reported to cause heartburn in sensitive individuals (Nash et al. 1986 Somerville et al. 1984). 

---