First-line drugs

The antimycobacterial drugs may be judiciously classified into two major categories, namely (a) First-Line Drugs, and b) Second-Line Drugs. 

The two aforesaid categories shall now be discussed individually in the sections that follows  

The first-line drugs used widely for tuberculosis are, namely isoniazid, rifampin, ethambutol, pyrazinamide, and sptreptomycin. 

The antituberculosis drugs viz. isoniazid, rifampin, and ethambutol have been duly treated under Newer Drugs for Newer Diseases -Chapter-30 whereas, streptomycin under Antibiotics -Chapter-25, and hence pyrazinamide shall be discussed as under  

Thermal decarboxylation of 2, 3-pyrazinedicarboxylic acid gives rise to the formation of the corresponding monocarboxylic acid derivative as an intermediate by the loss of one mole of CO2. The resulting product upon careful esterification with methanol followed by controlled aminolysis produces the desired pyrazinamide. 

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Desmopressin is the first-line drug choice in pediatric enuresis. 

The first-line drug for treating an acute attack of reentrant supraventricular tachycardia (SVT) is... 

Acetaminophen is recommended by the ACR as first-line drug therapy for pain management of OA. The dose is 325 to 650 mg every 4 to 6 hours on a scheduled basis (maximum dose 4 g/day maximum 2 g/day if chronic alcohol intake or underlying liver disease). Comparable relief of mild to moderate OA pain has been demonstrated for acetaminophen (2.6 to 4 g/ day) compared with aspirin (650 mg four times daily), ibuprofen (1,200 or 2,400 mg daily), and naproxen (750 mg daily). However, some patients respond better to NSAIDs. 

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. 

It is indicated for use as monotherapy or adjunctive therapy for partial seizures in adults and as monotherapy and adjunctive therapy for partial seizures in patients as young as 4 years of age. It is also a potential first-line drug for patients with primary, generalized convulsive seizures. 

Anxiety Disorder First-Line Drugs Second-Line Drugs Alternatives... 

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Overactive bladder Anticholinergic agentyantispas-modics Oxybulynin TDS (5.9 mg/day apply one patch twice weekly), tolterodine IR (1-2 mg twice daily), tolterodine LA (2-4 mg daily), trospium chloride (20 mg once or twice daily), solifenacin (5-10 mg daily), darifenacin (7.5-15 mg daily) Anticholinergics are first-line drug therapy (oxybulynin or tolterodine is preferred). 

Omeprazole (p. 167) can cause maximal inhibition of HCl secretion. Given orally in gastric juice-resistant capsules, it reaches parietal cells via the blood. In the acidic milieu of the mucosa, an active metabolite is formed and binds covalently to the ATP-driven proton pump (H+/K+ ATPase) that transports H+ in exchange for IC into the gastric juice. Lansoprazole and pantoprazole produce analogous effects. The proton pump inhibitors are first-line drugs for the treatment of gastroesophageal reflux disease. 

Valproic acid (VPA) is gaining increasing acceptance as a first-line drug it is less sedating than other anticonvulsants. Tremor, gastrointestinal upset, and weight gain are frequently observed reversible hair loss is a rarer occurrence. Hepatotoxicity may be due to a toxic catabolite (4-en VPA). 

Recommended for any form of active tuberculosis when treatment with first-line drugs (isoniazid, rifampin) has failed. Use only with other effective antituberculosis... 

Treatment to stop seizures is the next stage. Benzodiazepines can prevent the development of full status, and are the first-line drugs in the treatment of early status. They will stop seizures in about 80% of... 

A warning label from the FDA was introduced for thioridazine in 2000, advising against its use as a first-line drug, given concerns over QTc interval prolongation. 

TCAs derive their name from their chemical structure aU tricyclics have a three-ring nucleus. Currently, most clinicians are moving away from using TCAs as first-line drugs relative to the newer antidepressants, they tend to have more side effects, to require gradual titration to achieve an adequate antidepressant dose, and to be lethal in overdose. Some data suggest that TCAs may be more effective than SSRIs in the treatment of major depression with melancholic features (Danish University Antidepressant Group 1990 Perry 1996) however, many skilled clinicians and researchers continue to prefer the newer antidepressants, even for patients with melancholia, for the aforementioned reasons. Newer medications that affect both norepinephrine and serotonin (e.g., venlafaxine and mirtazapine) also may have superior efficacy in severely iU depressed patients or when remission is defined as the outcome (Thase et al. 2001). 

They are now first line drug in all grades of hypertension. They can be safely combined with diuretics and P blockers. 

Pyrazinamide is a first line drug. Resistance develops fast, if given alone, hence it is used in conjunction with isoniazid and rifampi-cin for shortcourse therapy. 

Risperidone and olanzapine are more effective than neuroleptics and safer than neuroleptics and clozapine, so they represent first-line choices. Quetiapine and ziprasidone are safer but may only be equal in efficacy to neuroleptics. The timing for clozapine is less certain with arguments put forth for earlier versus later introduction based on efficacy and safety issues, respectively. Clozapine is an important drug for the patients who have not fully remitted with first line drugs. 

Given this evidence, we believe that first-line drug therapy should include at least three separate trials with different SRIs, and one of them should be clomipramine. 

Although NSAIDs are now the first-line drugs for acute gout, colchicine was the primary treatment for many years. Colchicine is an alkaloid isolated from the autumn crocus, Colchicum autumnale. Its structure is shown in Figure 36-6. 

Disease Stage First-Line Drugs Alternative Drugs... 

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