Phenothiazines Antacids

The following drugp have a decreased pharmacologic effect when administered with an antacid corticosteroids, digoxin, chlorpromazine, oral iron products, isoniazid, phenothiazines, ranitidine, phenytoin, valproic acid, and the tetracyclines. 

Medications (analgesics, anticholinergerics, calcium channel blockers, clonidine, diuretics, phenothiazines, tricyclic antidepressants, iron supplements, calcium- and aluminum-containing antacids)... 

Drugs that may affect ACEIs may include antacids, capsaicin, indomethacin, phenothiazines, probenecid, and rifampin. Drugs that may be affected by ACEIs include allopurinol, digoxin, lithium, potassium preparations/potassium-sparing diuretics, and tetracycline. 

Aluminum Hydroxide + Magnesium Carbonate (Gaviscon Extra Strength/ Liquid) [OTC] [Antacid/Aluminum Magnesium Salts] Uses Relief of heartburn, acid indigestion Action Neutralizes gastric acid Dose Adults. 15-30 mL PO pc hs Peds. 5-15 mL PO qid or PRN avoid in renal impair Caution T Mg (w/ renal insuff) [C, ] Disp Liq, chew tabs SE Constipation, D Interactions In addition to AlOH effects OF histamine blockers, hydantoins, nitrofurantoin, phenothiazines, ticlopidine, T effects OF... 

When levodopa is given without a peripheral decarboxylase inhibitor, anorexia and nausea and vomiting occur in about 80% of patients. These adverse effects can be minimized by taking the drug in divided doses, with or immediately after meals, and by increasing the total daily dose very slowly antacids taken 30-60 minutes before levodopa may also be beneficial. The vomiting has been attributed to stimulation of the chemoreceptor trigger zone located in the brain stem but outside the blood-brain barrier. Fortunately, tolerance to this emetic effect develops in many patients. Antiemetics such as phenothiazines should be avoided because they reduce the antiparkinsonism effects of levodopa and may exacerbate the disease. 

Dicyclomine (Bentyl) [Anrimuscarinic, GI Anrispasmodic/ Anticholinergic] Uses Functional IBS Action Smooth-muscle relaxant Dose Adults. 20 mg PO qid T to 160 mg/d max or 20 mg EM q6h, 80 mg/d - qid then T to 160 mg/d, max 2 wk Feds. Infants >6 mo 5mg/dose tid-qid Children 10 mg/dose tid-qid Caution [B, -] Contra Infants <6 mo, NAG, MyG, severe UC, BOO Disp Caps, tabs, syrup, inj SE Anticholinergic SEs may limit dose Interactions T Anticholinergic effects W/ anticholinergics, antihistamines, amantadine, MAOIs, TCAs, phenothiazides T effects OF atenolol, digoxin X effects H7 antacids X effects OF haloperidol, ketoconazole, levodopa, phenothiazines EMS Avoid procainamide usage, may T adverse effects may T effects of digoxin, monitor... 

Antacids containing aluminium and magnesium reduce the gastrointestinal absorption of chlorpromazine and other phenothiazines by forming complexes (625). The clinical significance of this is unknown. 

PHENOTHIAZINES, SULPIRIDE ANTACIDS 1 levels of these antipsychotics 1 absorption Separate doses by 2 hours (in the case of sulpiride, give sulpiride 2 hours after but not before the antacid)... 

Clinically important, potentially hazardous interactions with aminophylline, amiodarone, antacids, antineoplastics, arsenic, bepridil, bismuth, bismuth subsalicylate, bretylium, calcium salts, cocoa, didanosine, disopyramide, duloxetine, erythromycin, iron, magnesium salts, meptazinol, methylxanthines, NSAIDs, phenothiazines, procainamide, quinidine, rasagiline, sotalol, sucralfate, tizanidine, tricyclic antidepressants, zinc... 

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