Beta-blockers side effects

The success of quinine inspired the search for other antimalarials. The greatest impetus for the development of synthetic dmgs came this century when the two World Wars intermpted the supply of cinchona bark to the combatants. A stmcturally related 4-quinolinemethanol is mefloquine (65, Lariam [51773-92-3]) which now serves as an effective alternative agent for chloroquine-resistant P. falciparum. This is a potent substance that requires less than one-tenth the dose of quinine to effect cures. There are some untoward side effects associated with this dmg such as gastrointestinal upset and dizziness, but they tend to be transient. Mefloquine is not recommended for use by those using beta-blockers, those whose job requires fine coordination and spatial discrimination, or those with a history of epilepsy or psychiatric disorders. A combination of mefloquine with Fansidar (a mixture of pyrimethamine and sulfadoxine) is known as Fansimef but its use is not recommended. Resistance to mefloquine has been reported even though the compound has not been in wide use. 

Some of the side effects due to beta blockers such as the slowing of heart rate can be counteracted by administration of drugs which antagonize the alpha adrenergic receptors. The... 

Brismar, K., Hylander, B., Eliasson, K., Rossner, S. Wetterberg, L. (1988). Melatonin secretion related to side-effects of beta-blockers from the central nervous system. Acta Med. Scand. 223, 525-30. 

The side effects of beta blockers include decreased blood pressure, dizziness, and sedation. They are also believed by some to worsen symptoms of depression in vulnerable individuals, though how beta blockers such as atenolol that do not enter the brain might do so is not readily understandable. In addition, beta blockers should be avoided in diabetic patients because they may dangerously mask the symptoms of hypoglycemia. Finally, beta blockers should not be taken by patients with emphysema (COPD) or asthma. 

It s generally wise to instruct patients to take a test dose of the beta blocker in the safety of their homes before the performance situation, to be certain that they can tolerate any side effects, especially potential dizziness. 

The beta blocker propranolol (Inderal) has been studied in the treatment of impulsivity and appears to provide a slight benefit to some patients. It can be started at a dose of 10 mg taken three times per day and increased gradually to a maximum of 200mg/day. Side effects of propranolol include depression, fatigue, lowered blood pressure, impotence, and a worsening of symptoms in patients with asthma. 

The beta blockers can cause a wide array of side effects including low blood pressure, slowed heart rate, dizziness, fatigue, and impotence. They may exacerbate asthma and depression, though this remains controversial, in vulnerable patients. Symptomatic bradycardia (slow pulse) and depression are probably less problematic when using pindolol, which in addition to blocking noradrenergic activity also increases serotonergic activity. 

Co-codamol is a combination of paracetamol (nonnapioid analgesic) and codeine (opioid analgesic). One of the side-effects of opioids is constipation. Naprosyn is a proprietary (trade name) preparation of the non-steroidal antiinflammatory drug naproxen Adalat is a proprietary preparation of the calcium-channel blocker nifedipine Amoxil is a proprietary preparation of the beta-lactam amoxicillin and Dulco-lax is the brand name of the stimulant laxative bisacodyl. 

Common side-effects associated with beta-adrenoceptor blockers, such as atenolol, include fatigue, bradycardia, sleep disturbances, and peripheral vasoconstriction leading to coldness of extremities. Water-soluble beta-blockers, such as atenolol, are less likely to cause sleep disturbances and nightmares than lipid-soluble beta-blockers, such as propranolol. 

Drugs that may increase the effects or side effects of bupropion include levodopa, MAOIs, ritonavir, antidepressants, antipsychotics, beta blockers, type 1C antiarrhythmics. 

Geriatric Considerations - Summary Systemic absorption of ophthalmic drugs may occur and cause adverse effects in older adults. Since betaxolol is beta-selective, cardiovascular, respiratory and CNS adverse effects occur less frequently than with beta-nonselective topical opthalmics. These effects may still occur therefore close monitoring for systemic side effects is warranted. Betaxolol maybe less effective than the nonselective topical beta-blockers with an average lOP reduction of 18%-26%. Tachyphylaxis may occur after long-term therapy. 

The most common side effects are Raynaud s phenomenon with cold or even cyanotic distal extremities and digits, tiredness or weakness, bradycardia, and sexual impotence. Less common side effects are depression and dysphoria, bronchoconstriction, congestive heart failure, hallucinations, hypotension, vomiting or nausea, diarrhea, insomnia and nightmares, dizziness, and hypoglycemia. When due attention is paid to contraindications and the treatment is carefully monitored, the side effects of beta-blocker treatment are generally mild. 

It is another nonselective beta blocker with longer duration of action and mainly used in hypertension. It is excreted largely in urine and does not cross blood-brain barrier and has no central side effects. 

Astrup AV. Fedme og diabetes som bivirkninger til beta-blockkere. [Obesity and diabetes as side-effects of beta-blockers.] Ugeskr Laeger 1990 152(40) 2905-8. 

Nonselective beta blockers (i.e., those with a fairly equal affinity for beta-1 and beta-2 receptors) may produce bronchoconstriction in patients with asthma and similar respiratory disorders. Cardiovascular side effects include excessive depression of heart rate and myocardial contractility as well as orthostatic hypotension. Some of the traditional beta blockers may impair glucose and lipid metabolism, but this effect can be reduced by using one of the newer vasodilating beta blockers such as carvedilol.97 Other side effects include depression, fatigue, gastrointestinal disturbances, and allergic reactions. Beta blockers are generally well tolerated by most patients, however, and the incidence of side effects is relatively low. 

The side effects and problems associated with beta blockers were addressed in Chapter 20. The primary problem associated with these drugs is that they may cause excessive inhibition of the heart, resulting in an abnormally slow heart rate and reduced contraction force. This effect is especially problematic in heart failure because the heart is already losing its ability to pump blood. Nonetheless, the risk of this and other side effects is acceptable in most people with heart failure, and this risk is minimized by adjusting the dosage... 

In terms of ADMET, following oral administration about half of the atenolol dose is absorbed. Plasma-protein binding is minimal (3-5%). Peak plasma concentrations, as well as peak action, are reached in 2-4 h. Atenolol has low lipid solubility, and only small amounts cross the blood-brain barrier. Thus, atenolol s CNS side effects are less than with other beta-blockers [75]. Atenolol is excreted mainly by the kidneys, with little or no hepatic metabolism. It crosses the placenta, and concentrations in breast milk can be similar or even higher than those in maternal blood [76]. Atenolol is not recommended in asthma, even though its high beta-1 selectivity makes it safer in obstructive pulmonary disease than nonselective beta-blocking agents. Atenolol s important ADMET characteristics are listed in Tab. 8.2. 

He should be advised to take his aspirin in the morning after food. The tablet may be dispersed in water or taken whole with some water. The beta-blocker should be taken regularly at the time(s) prescribed, at the same time each day, swallowed whole with a drink of water. Mr Jones should be told that if he experiences side-effects with this medication, such as dizziness, he should not stop taking it suddenly but should speak with his GP or pharmacist. 

With some drugs that are delivered via eye drops, some systemic absorption can occur which in turn can cause systemic side-effects. For example, timolol (a beta-blocker) can worsen or precipitate bronchospasm in asthmatic and COPD patients. 

Guttate psoriasis is more often associated with children or young adults. It is characterised by small, red spots (not as deep or large as plaque psoriasis) on the skin, usually on the trunk of the body. Its onset can be rapid and has been associated with infections, particularly of the upper respiratory tract, or as a side-effect of certain drugs, including beta-blockers. 

Q5 Beta-blockers can have a number of adverse effects. In fact, all drugs used to treat hypertension have some side effects. Beta-adrenoceptor antagonists are... 

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