NSAIDs Phenothiazines

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... 

Drugs that are likely to cause phototoxic reactions are amiodarone, nalidixic acid, various NSAIDs, phenothiazines (especially chlorpromazine), and tetracyclines (particularly demedocydine). 

Photoallergic reactions may occur as a result of exposure to systemically administered drugs such as griseofulvin, NSAIDs, phenothiazines, quinidine, sulfonamides, sulfonylureas, and thiazide diuretics as well as to external agents such as para-aminobenzoic acid (found in sunscreens), bithionol (used in soaps and cosmetics), paraphenylenediamine, and others. 

Allopurinol, barbiturates, benzodiazepines, captopril, carbamazepine, erythromycin, fluoroquinolones, isoniazid, NSAIDs, penicillins, phenothiazines, phenytoin, rifampin, sulfonamides antimicrobials, and tetracyclines... 

Drugs that may affect repaglinide include CYP 450 inhibitors (eg, clarithromycin, erythromycin, ketoconazole, miconazole), CYP 450 inducers (eg, barbiturates, carbamazepine, rifampin), beta blockers, calcium channel blockers, chloramphenicol, corticosteroids, coumarins, estrogens, gemfibrozil, isoniazid, itraconazole, levonorgestrel and ethinyl estradiol, MAOIs, nicotinic acid, NSAIDs, oral contraceptives, phenothiazines, phenytoin, probenecid, salicylates, simvastatin, sulfonamides, sympathomimetics, thiazides and other diuretics, and thyroid products. 

Drugs that may be affected by SSRIs Drugs that may be affected by SSRIs include alcohol, benzodiazepines, beta blockers, buspirone, carbamazepine, cisapride, clozapine, cyclosporine, diltiazem, digoxin, haloperidol, hydantoins, lithium, methadone, mexiletine, nonsedating antihistamines, NSAIDs, olanzapine, phenothiazines, phenytoin, pimozide, procyclidine, ritonavir, ropivacaine, sumatriptan, sulfonylureas, sympathomimetics, tacrine, theophylline, tolbutamide, tricyclic antidepressants, and warfarin. 

Altered homeostasis in older persons can lead to important and common adverse drug effects the less robust homeostatic milieu may be stressed by drugs, causing adverse effects. Examples include orthostatic hypotension due to antihypertensives and other agents that cause a-adrenergic blockade (e.g. terazosin, doxazosin, tricyclic antidepressants and phenothiazines) in those with barorecep-tor dysfunction. Diuretics can cause hyponatraemia or hypokalaemia in older patients, whereas ACE inhibitors and NSAIDs can cause hyperkalaemia. 

Drug interactions NSAIDs Salicylates Sulfonamides Chloramphenicol Probenecid Coumarins MAO inhibitors Beta-blockers Thiazides and other diuretics Corticosteroids Phenothiazines Thyroid products Estrogens Oral contraceptives Phenytoin Nicotinic acid Sympathomimetic Calcium channel blockers Isoniazid Miconazole... 

Specific cell injury or cell functional disorder occur with individual drugs or drug classes, e.g. tardive dyskinesia (dopamine receptor blockers), retinal damage (chloroquine, phenothiazines), retroperitoneal fibrosis (methysergide), NSAIDs (nephropathy). Cancer may occur, e.g. with oestrogens (endometrium) and with immunosuppressive (anticancer) drugs. 

In a review of photopatch-testing in 2390 patients with rashes that were confined to sun-exposed areas, about 70% of 4374 positive reactions were classified as photo-induced reactions, of which 222 (5%) were photoaUergic reactions (6). NSAIDs, disinfectants, and phenothiazines were the main photoallergens. Photosensitive reactions to antimicrobial drugs, including topical agents, have been reviewed (7). 

A whole host of drugs can give rise to purpura, the most common being NSAIDs, thiazide diuretics, phenothiazines, cytostatics, gold, penicillamine, hydantoins, thiouracils, and sulfonamides. 

Patients must not be taking other photosensitizing drugs, for example phenothiazines and benzodiazepines (Chapter 12), NSAIDs (Chapter 7) and some antibiotics (Chapter 9). 

Consider also Opioids + Phenothiazines , p.l80, Opioids + NSAIDs , p.l77, and Opioids + Tricyclic and related antidepressants , p.l87. 

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