Contraindications antagonistic effects

Contraindications relating to herbal combinations which have dangerous or antagonistic effects... 

The P-blockers propranolol and timolol are FDA-approved for migraine prophylaxis, but other drugs in the class are also as effective.46 Cautious dosage titration is advised for those patients who do not have other indications for P-blocker use. Rizatriptan interacts with propranolol and thus dosages must be titrated downward, or another triptan chosen for abortive therapy.36 Comorbid reactive airway disease is a relative contraindication to P-blocker prophylaxis, and patients with cardiac conduction disturbances should be closely monitored. Calcium channel antagonists are often used when patients cannot tolerate P-blockers. They are purported to beneficially... 

Fever, rigors, chills, malaise headaches, myalgia Nausea, emesis Neutropenia Hepatic enzyme elevation Cutaneous—alopecia, transient, mild rashlike reaction Acetaminophen (APAP). NSAID if APAP is not effective. Meperidine for severe chills and rigors. Bedtime administration. 5-HT3 antagonist, prochlorperazine, metoclopramide, fluids Weekly complete blood count reduce dose by 30-50% Liver function tests (LFTs) weekly withhold treatment until LFTs normalize restart at 30-50% dose reduction reversible on dose reduction or cessation. Interferon is contraindicated in patients with psoriasis because exacerbation of psoriasis has been noted during IFN therapy. 

In symptomatic patients, medical therapy can be tailored either to control ventricular response or to restore sinus rhythm. Nondihydropyridine calcium antagonists (e.g., verapamil) are considered first-line drug therapy for decreasing ventricular response. Type I agents (e.g., procainamide, quinidine) are only occasionally effective in restoring sinus rhythm. DCC is ineffective, and /3-blockers are usually contraindicated because of coexisting severe pulmonary disease or uncompensated HF. 

Cephalexin is considered safe and effective. Nitrofurantoin should not be used after week 37 due to concern for hemolytic anemia in the newborn. Sulfa-containing drugs may increase risk for kernicterus in the newborn and should be avoided during the last weeks of gestation. Folate antagonists, such as trimethoprim, are relatively contraindicated during the first trimester because of their association with cardiovascular malformations. Fluoroquinolones and tetracyclines are contraindicated. 

The triazolopyridine trazodone does not have an appreciable effect on the re-uptake of the neurotrans-mittors dopamine or noradrenaline. It is a weak inhibitor of serotonin re-uptake but is a potent antagonist of the serotonin 5-HT2 receptor. Clinical experience has shown unpredictable efficacy. Trazodone has little antimuscarinic activity and has little if any action on cardiac conduction. Like mianserin it can therefore safely be used in patients for which anticholinergics are contraindicated and there are no absolute contraindications for patients with concomitant diseases of the cardiovascular system. 

Nitroglycerin will be effective for on-going chest pain relief. Ca channel antagonists and long-acting Nitrates can be used when jS-blockers are contraindicated. These drugs may be also used for the initial therapy, additional to -blockers or when jS-blockers treatment failed. However, for the effectiveness of vasodilatation itself is relatively weaker evidence. 

Ketamine has been traditionally contraindicated in patients with increased ICP or reduced cerebral compliance because it increases CMR02, CBF and ICP. These deleterious effects can be antagonised by the concomitant administration of propofol, or thiopentone, and benzodiazepines. Furthermore, ketamine is an antagonist at the NMDA receptor. Nevertheless, ketamine can adversely affect neurological outcome in the presence of brain ischaemia. 

The toxicity of therapeutic doses of ACTH resembles that of the glucocorticoids (see Chapter 39 Adrenocorticosteroids Adrenocortical Antagonists), with the added adverse effect of hyperandrogenism in women. The occasional development of antibodies to animal ACTH or to depot cosyntropin (a preparation not currently available in the USA) has produced anaphylactic reactions or refractoriness to ACTH therapy in a few individuals. Painful swelling occurs at the injection site more often with the zinc hydroxide depot preparation than with the gelatin preparation. Contraindications are similar to those of glucocorticoids. When immediate effects are desired, glucocorticoids are preferable. 

Topical doxepin hydrochloride 5% cream (Zonalon) may provide significant antipruritic activity when utilized in the treatment of pruritus associated with atopic dermatitis or lichen simplex chronicus. The precise mechanism of action is unknown but may relate to the potent Hi and H2-receptor antagonist properties of dibenzoxepin tricyclic compounds. Percutaneous absorption is variable and may result in significant drowsiness in some patients. In view of the anticholinergic effect of doxepin, topical use is contraindicated in patients with untreated narrow-angle glaucoma or a tendency to urinary retention. 

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