Headache placebo

Steiner TJ, et al. Aspirin in episodic tension-type headache placebo-controlled dose-ranging comparison with paracetamol. Cephalgia 2003 23 59-66. 

Venlafaxine (48) is a stmcturaHy novel phenylethylamine derivative that strongly inhibits both noradrenaline and serotonin reuptake. It lacks anticholinergic, antihistaminergic, and antiadrenergic side effects. As compared to placebo, most common adverse events are nausea, somnolence, dizziness, dry mouth, and sweating. Venlafaxine-treated patients also experienced more headaches and nausea, but less dry mouth, dizziness, and tremor than patients treated with comparator antidepressants. 

For some conditions, a large placebo effect can be anticipated. For example, studies of hormone replacement therapies for hot flashes in postmenopausal women consistently show a 50% decline from baseline in the number of daily hot flashes in the placebo group. Therefore, in order to show significance, an active treatment must produce an effect that is substantially larger than 50%. A marked placebo response is commonly observed with any condition that has a subjective component, such as chronic pain (e.g. arthritis), episodic pain (e.g. headaches), psychological states (e.g. anxiety), and certain physiologic measurements (e.g. blood pressure). 

A very common analysis in clinical trials involves the analysis of two binomial variables to see if there is a statistically significant association between them. A binomial variable is one that can have only one of two values. For example, let s assume that we have a variable called treatment whose value is either a 1 to indicate active drug therapy or a 0 to indicate placebo. We also have a variable called headache whose value is a 1 if the patient experiences headache after therapy and a 0 if not. What we want to know is whether a change in the level of therapy is significantly associated with a change in the level of headache. The 2x2 table looks like this ... 

How does physical exercise alleviate depression One possibility is that it increases the release of endorphins that produce a sense of well-being, sometimes referred to as the runner s high . Another possibility is that it is a placebo effect. But even if it is a placebo effect, consider the differences between exercise and antidepressants in side effects. Side effects of antidepressants include sexual dysfunction, nausea, vomiting, insomnia, drowsiness, seizures, diarrhoea and headaches. Side effects of physical exercise include enhanced libido, better sleep, decreased body fat, improved muscle tone, greater life expectancy, increased strength and endurance and improved cholesterol levels. So if both antidepressants and exercise work by means of the placebo effect, which placebo would you prefer ... 

The vaccine is well tolerated with injection site reactions and headache and fatigue occurring as commonly as in placebo groups. 

A review of case reports, clinical trials, post-marketing surveillance, and drug monitoring studies concurrently showed that the most common side effects were gastrointestinal, dizziness/confusion, and sedation (Ernst et al. 1998). Importantly, the side effects of hypericum in this study were comparable to placebo levels. A pharmacokinetic study showed that plasma levels of up to 300 ng/ml were well tolerated. Headache occured in one subject who was taking 1200 mg extract (59 mg hyperforin, plasma cone. >400 ng/ml) (Biber et al. 1998). 

Adverse reactions at therapeutic doses are usually minimal and transient. With long-term use, initial side effects usually disappear. The following reactions were reported in 2 heart valve replacement trials comparing dipyridamole and warfarin therapy to either warfarin alone or warfarin and placebo dizziness, abdominal distress, headache, and rash. 

Nasal spray - Administer 1 dose of 5 mg for the treatment of acute migraine. If the headache returns, the dose may be repeated after 2 hours. Do not exceed a maximum daily dose of 10 mg in any 24-hour period. Individuals may vary in response to zolmitriptan. The pharmacokinetics of a 5 mg nasal spray dose is similar to the 5 mg oral formulations. Doses lower than 5 mg can only be achieved through the use of an oral formulation. Therefore, choose the dose and route of administration on an individual basis. The efficacy of a second dose has not been established in placebo-controlled trials. 

---