Side effects muscle relaxants

Anxiolytics are drugs used for the treatment of anxiety disorders. Apart from benzodiazpines, a frequently used anxiolytic is the 5HT1A (serotonin) receptor agonist buspiron, which has no sedative, amnestic or muscle-relaxant side effects, but whose action takes about a week to develop. Furthermore, it is less efficaceous than the benzodiazepines. Buspiron s mechanism of action is not fully understood. 

Side effects may be as mild and rare as headache, nausea, and stomach upset for saw palmetto [23,24], However, some supplements may have serious side effects. Hypertension, euphoria, restlessness, nervousness, insomnia, skin eruptions, edema, and diarrhea were reported in 22 patients following long-term ginseng use at an average dose of 3 g of ginseng root daily [38]. Side effects reported with valerian use include headaches, hangover, excitability, insomnia, uneasiness, and cardiac disturbances. Valerian toxicity including ataxia, decreased sensibility, hypothermia, hallucinations, and increased muscle relaxation have been reported [39]. 

Zolpidem, chemically unrelated to benzodiazepines or barbiturates, acts selectively at the y-aminobutyric acidA (GABAA)-receptor and has minimal anxiolytic and no muscle relaxant or anticonvulsant effects. It is comparable in effectiveness to benzodiazepine hypnotics, and it has little effect on sleep stages. Its duration is approximately 6 to 8 hours, and it is metabolized to inactive metabolites. Common side effects are drowsiness, amnesia, dizziness, headache, and GI complaints. Rebound effects when discontinued and tolerance with prolonged use are minimal, but theoretical concerns about abuse exist. It appears to have minimal effects on next-day psychomotor performance. The usual dose is 10 mg (5 mg in the elderly or those with liver impairment), which can be increased up to 20 mg nightly. Cases of psychotic reactions and sleep-eating have been reported. 

Sodium nitroprusside (SNP), which is also known as Nipruss or Nipride to medical practitioners, was the first iron nitrosyl complex, prepared as far back as 1850 by Playfair [40]. The hypotensive property of SNP was first demonstrated by Johnson [41] in 1929. It was shown that application of a moderate dose of SNP reduces the blood pressure of a severely hypertensive patient without any side effect [42]. Since that time considerable research has been carried out to understand the mode of action of nitroprusside and its metabolic fate. SNP is now regarded as a potent vasodilator that causes muscle relaxation by releasing NO which activates the cytosolic isozyme of guanylyl cyclase [43-46]. 

Drugs that increase sedation and give muscle relaxation can have a negative effect on muscle strength and the ability to maintain physical activity, for example, benzodiazepines and other tranquilizers. Corticosteroids have a well known side effect on muscle tissue that leads to muscle atrophy and increases with the dosage. 

Another interesting alkaloid is tubocurarine chloride (14), with a bisbenzyliso-quinoline structure. It is the active principle of tubocurare, an arrow poison used by Indians in South America and medicinally used as a muscle relaxant. However, the source, the leaves of the tropical rainwood liane Chondodenron tomento-sum, is not easily accessible and the compound exhibits unwanted side-effects. Investigations showed that the basic structure can be replaced by an appropriate steroid skeleton with two nitrogen substituents at the right distance (see next section). 

In addition to parkinsonism, another extrapyramidal side effect is the so-called acute dystonic reaction in which muscles (usually of the face or neck) go into an acute spasm. A dystonic reaction is painful and unpleasant, usually occurs early in treatment, and sometimes occurs after the very first dose of an antipsychotic. Another extrapyramidal symptom is akathisia, a restless inability to relax and sit still. Akathisia can range from a mild restlessness to extreme agitation. Rarely, patients have been known to attempt suicide during severe episodes of akathisia. It is easy to overlook akathisia, because it can easily be mistaken for a worsening of psychosis or anxiety. 

Atracurium is a non-depolarising muscle relaxant, which may cause respiratory depression as a side-effect. 

The development of the benzodiazepine class of drugs for the treatment of a variety of neurological indications has proven to be an outstanting success story in the field of chemotherapy. However, these compounds often produce undesirable side effects when used as anti-anxiety or hypnotic agents. These side effects include sedation, physical dependence, amnesia, muscle relaxation, and ethanol potentiation. The development of a benzodiazepine receptor-based anxiolytic agent devoid of these side effects would constitute a major advance in the field and has been the focus of significant research efforts [284]. 

Buspirone is an extremely specific drug that could possibly represent a new chemical class of anxiolytics—azaspirones. As an anxiolytic, its activity is equal to that of benzodiazepines however, it is devoid of anticonvulsant and muscle relaxant properties, which are characteristic of benzodiazepines. It does not cause dependence or addiction. The mechanism of its action is not conclusively known. It does not act on the GABA receptors, which occurs in benzodiazepine use however, it has a high affinity for seratonin (5-HT) receptors and a moderate affinity for dopamine (D2) receptors. Buspirone is effective as an anxiolytic. A few side effects of buspirone include dizziness, drowsiness, headaches, nervousness, fatigue, and weakness. This drug is intended for treatment of conditions of anxiety in which stress, muscle pain, rapid heart rate, dizziness, fear, etc. are observed in other words, conditions of anxiety not associated with somewhat common, usual, and everyday stress. Synonyms for buspirone are anizal, axoren, buspar, buspimen, buspinol, narol, travin, and others. 

Minoxidil is a peripheral vasodilator that directly relaxes vascular smooth musculature, thus, lowering systolic and diastolic pressure. Its action is linked to the activation of calcium channels. Open calcium channels cause hyperpolarization of smooth muscle cells, which in turn, reduces the flow of calcium ions into the cell, which is necessary for supporting vascular tonicity. However, when taking minoxidil, tachycardia, elevated renin secretion, and water and sodium ion retention all appear simultaneously with hypotension. Because of potentially serious side effects, it is used only for severe hypertension that does not respond to treatment with other drugs, and absolutely in combination with two other antihypertensive drugs. A synonym of this drug is loniten. 

Magnesium sulfate, applied intravenously is often used as tocolytic. The mechanism of action is not completely clear but might involve a competition with calcium on the cellular level. Precautions in the sense of magnesium plasma level monitoring must be taken in patients with renal insufficiency since this divalent kation is eliminated by the kidneys. Relatively high plasma concentrations are necessary to achieve a sufficient tocolysis. The relatively frequent side effects are respiratory depression, depressed reflexes, headaches, palpitation and skin flushing in the mother and muscle relaxation and, rarely, CNS depression in the fetus. 

Dicyclomine (Bentyl), oxybutynin (Ditropan), and tolterodine (Detrol) are nonselective smooth muscle re-laxants that produce relatively little antagonism of muscarinic receptors at therapeutic concentrations. The mechanism of relaxation is not known. Finally, some other classes of drugs can act in part as muscarinic antagonists. For example, the antipsychotics and antidepressants produce antimuscarinic side effects (e.g., dry mouth). 

Benzodiazepines also possess muscle relaxant activity. Their pharmacology is discussed in Chapter 30. Diazepam Valium) has been used for control of flexor and extensor spasms, spinal spasticity, and multiple sclerosis. The muscle relaxant effect of the benzodiazepines may be mediated by an action on the primary afferents in the spinal cord, resulting in an increased level of presynaptic inhibition of muscle tone. Polysynaptic reflexes are inhibited. The most troublesome side effect is drowsiness, which is dose dependent. Tolerance to both the therapeutic effects and the side effects develops. 

The generally excellent tolerability of these preparations has contributed greatly to the widespread use of anxiolytics. The commonest side effects (Table 1.11) are tiredness and muscle relaxation and these usually can be avoided or attenuated by reducing the dose. Ataxia and paradoxical reactions such as irritability and increased agitation occasionally arise in the elderly but are rare in younger patients. Much attention has been focused on the negative effects of benzodiazepines on memory and other cognitive functions (see Chapter 7). 

Mephenesin was the first drug used as muscle relaxant but due to its serious side effects e.g. haemolysis, hypotension and thrombophlebitis, it is not clinically used now. 

Midazolam has also been used as an effective medication in palliative medicine when symptom management supersedes the problem of side effects (372, 373). It is used for a variety of indications, including for terminal agitation, for muscle relaxation, and as an anticonvulsant. Recommended therapy is a loading... 

Papaverine Papaverine, molecular formula C20H21NO4, is an isoquinoline alkaloid isolated from poppy seeds Papaver somniferum, family Papaveraceae). This alkaloid is used mainly in the treatment of spasms and of erectile dysfunction. It is also used as a cerebral and coronary vasodilator. Papaverine may be used as a smooth muscle relaxant in microsurgery. In pharmaceutical preparations, papaverine is used in its salt form, e.g. hydrochloride, codecarboxylate, adenylate and teprosylate. The usual side-effects of papaverine treatment include polymorphic ventricular tachycardia, constipation, increased transaminase levels, hyperbihr-unemia and vertigo. 

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