Once-daily administration

Donepezil has the advantage of once-daily administration and appears to be better tolerated than tacrine. Tacrine is particularly harmful to the liver. The new dragp rivastigmine and galantamine, like the other two, are effective in treating mild-to-moderate dementia of AD. 

The individual responsiveness to desmopressin is consistent, and a test dose administered at the time of diagnosis or prior to therapy is the best predictor of response. Generally, DDAVP is more effective in vWD than in hemophilia patients, with an average 30% to 50% increase in vWF and factor VIII levels. In patients with an adequate response, desmopressin is first-line therapy because it allows for once-daily administration (elevates plasma levels for 8-10 hours), does not pose a threat in terms of viral transmission, and the cost is substantially less than that of the plasma-derived products. Fibrinolysis inhibitors (50-60 mg/kg of aminocapriotic acid every 4—6 hours or trenex-amic acid 10-15 mg/kg every 8-12 hours) and OCs are used successfully in the management of epistaxis and menorrhagia or as adjuvant treatments. 

After the submission of this paper several publications have appeared in the literature that reinforce the role of rifaximin in the treatment of infectious diarrhea [1]. An entire issue of the Journal of Travel Medicine devoted to the use of this antibiotic in the treatment of traveler s diarrhea (TD) has been published [2-5], In addition, a recent paper from our laboratory [6] confirmed the rifaximin efficacy also in enteroaggregative Escherichia coli-mediated TD. Furthermore, in a randomized, double-blind, placebo-con-trolled study [7] even once daily administration of the antibiotic proved to be capable of preventing TD. Finally, Lawler and Wallace [8] recently reviewed the treatment options for bacterial diarrhea and considered rifaximin a useful addition to our therapeutic armamentarium. 

There are pharmacokinetic differences among /1-blockers in first-pass metabolism, serum half-lives, degree of lipophilicity, and route of elimination. Propranolol and metoprolol undergo extensive first-pass metabolism. Atenolol and nadolol have relatively long half-lives and are excreted renally the dosage may need to be reduced in patients with moderate to severe renal insufficiency. Even though the half-lives of the other /J-blockers are much shorter, once-daily administration still may be effective. /J-Blockers vary in their lipophilic properties and thus CNS penetration. 

Rotigotine is available as a transdermal patch for once-daily administration, initiated at 2 mg/day and increased by 2 mg/day on a weekly basis to a maximum of 6 mg for early PD. 

Tablets, extended-release Intended for once daily administration. Patients treated with diltiazem alone or in combination with other medications may be switched safely to once daily extended-release diltiazem tablets at the nearest equivalent total daily dose. Subsequent titration to higher or lower doses may be necessary and should be initiated as clinically warranted.

Tablets, extended release - The extended-release tablets are for once daily administration. When switching from immediate-release metoprolol tablets to extended-release, use the same daily dose.

Avinza- Avinza capsules are a modified-release formulation of morphine sulfate indicated for once-daily administration for the relief of moderate to severe pain requiring continuous, around-the-clock opioid therapy for an extended period of time. Avinza capsules are to be swallowed whole or the... 

Absorption/Distribution - Following oral administration, entecavir peak plasma concentrations occurred between 0.5 and 1.5 hours. Steady state was achieved after 6 to 10 days of once-daily administration. The bioavailability of... 

Therapy-experienced patients - The recommended dosage is 400/100 mg (3 capsules or 5 mL taken with food, or 2 tablets taken with or without food) twice daily. Once daily administration of lopinavir/ritonavir is not recommended in therapy-experienced patients. 

Didanosine EC (Videx EC) In combination with other antiretroviral agents for treatment of HIV-1 infection in adults whose management requires once-daily administration of didanosine or an alternative didanosine formulation. There are limited data to date to support the long-term durability of response with a once-daily regimen of didanosine. 

Protease inhibitor (Pl)-expehenced patients Fosamprenavir 700 mg twice daily plus ritonavir 100 mg twice daily. Once-daily administration of fosamprenavir plus ritonavir is not recommended in Pl-experienced patients. 

In the treatment of hypertension it seems preferable to choose a selective /3i-blocker with a sufficiently long duration of action, thus allowing once daily administration. 

Synthetic levothyroxine sodium is used most commonly and is the drug of choice. Oral doses are incompletely absorbed. In plasma levothyroxine is for more than 99% bound to proteins, mainly to TBG. Maximal effects are reached in 3 weeks and the activity persists for 1-3 weeks after withdrawal of chronic therapy. It has a half-life of 7 days which permits once-daily administration. Its adverse effects mainly consist of signs and symptoms of hyperthyroidism. 

Levothyroxine sodium (Levothwid, Synthroid, Levoxine) is the sodium salt of the naturally occurring levorota-tory isomer of T4. It is the preparation of choice for maintenance of plasma T4 and T3 concentrations for thyroid hormone replacement therapy in hypothyroid patients. It is absorbed intact from the gastrointestinal tract, and its long half-life allows for convenient once-daily administration. Since much of the T4 is deiodi-nated to T3, it is usually unnecessary to use more expensive preparations containing bothX4 and Tj.The aim is to establish euthyroidism with measured serum concentrations of T4, T3, and TSH within the normal range. 

Compared to ipratropium is more expensive, but once-daily administration will likely improve adherence with therapy... 

Synthetic levothyroxine is the preparation of choice for thyroid replacement and suppression therapy because of its stability, content uniformity, low cost, lack of allergenic foreign protein, easy laboratory measurement of serum levels, and long half-life (7 days), which permits once-daily administration. In addition, T4 is converted to T3 intracellularly thus, administration of... 

Once-daily administration of modified-release formulation of fluvastatin 80-320 mg/day was generally safe and well tolerated in 40 patients with primary hypercholesterolemia over 13 days (7). However, fluvastatin 640 mg in this formulation was not well tolerated six of seven patients had adverse events, including diarrhea, headache, and rises in serum transaminases. In addition, the pharmacokinetics of fluvastatin were non-linear at this dose, possibly because of saturation of first-pass metabolism, causing higher than expected serum drug concentrations. 

Theeuwes, F., Swanson, D. R., Guittard, G., et al. Osmotic delivery systems for the beta-adrenoceptor antagonists metoprolol and oxprenolol Design and evaluation of systems for once-daily administration. Br. J. Clin. Pharmacol. 19 (suppl 2) 69S-76S, 1985. 

Nisoldipine (Fig. 7.7) is an analogue of nifedipine, but it is at least five to ten times more potent than nifedipine on arterial smooth muscle, without affecting myocardial contractility. It also possesses a very potent and selective relaxation activity on small arteries, and therefore it can be used for the treatment of hypertension. Since its duration is limited by a massive hepatic first-pass effect, it is currently used as an extended-release formulation for once-daily administration. 

Although ciprofloxacin for oral and intravenous administration already displayed a very high standard of antibacterial activity and tolerance, some properties still required optimization. These included the need for improved activity against Gram-positive pathogens (e.g., S. pneumoniae) and anaerobic bacteria, and kinetic properties allowing once-daily administration. The properties required by Bayer of the third-generation quinolones were therefore as follows. 

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